Custom JUnit5 Test Engines @Java.IL – the Israeli Java Community – 2020

August 17, 2020

< 1 min read


JUnit5 – Custom TestEngines

JUnit5 has been out for some time now, but what are the hidden pearls you can find inside the new Junit Platform? This session explores the possibilities, from @Test over custom extensions up to your own TestEngine. The presentation shows you how to manage a full-stack test in different flavours, based on the JUnit5 possibilities. The main focus is on the development of a custom TestEngine to support project-specific needs. After this, you’ll have all the bits and bytes you need for starting your journey with JUnit5.

View Slides Here

Speakers

Sven Ruppert

    Sven Ruppert

    Developer Advocate

    Sven is working as Developer Advocate for Jfrog and coding Java since 1996 in industrial projects. He was working over 15 years as a consultant worldwide in industries like Automotive, Space, Insurance, Banking, UN and WorldBank. He is regularly speaking at Conferences and Meetups worldwide and contributes to IT periodicals, as well as tech portals. Additional to his main topic DevSecOps he is working on Mutation Testing of Web apps and Distributed UnitTesting besides his evergreen topics Core Java and Kotlin.

    Video Transcript

    hello again so this time in israel about
    virtua
    so i don’t know if any one of you attend
    my i think it was functional director
    from
    the workshop we had did some some time
    ago
    so the most critical part now and so
    really
    the biggest challenge for me is now how
    to share my screen
    so i will try now um i hope that
    i have the right for it already
    then i will try so
    and here we are so what i’m not doing is
    uh going to this presentation
    because then i’m losing the focus
    between zoom and all this stuff again
    and again so it’s it’s just too
    complicated for me so
    um i think you can see the slides um
    [Music]
    and yeah that’s it so
    jonah five and then we want to talk a
    little bit about custom test engines
    um yeah as you heard already i’m working
    for jfrog i’m sven
    i’m a developer advocate for jfrog i
    think about j i don’t have to say
    too much
    i think most people of you know it
    already
    and well if you have any questions or
    whatever after the talk or
    someday the easiest way to reach me is
    definitely twitter
    not email please don’t use my email
    address
    um what we want to do today
    first of all i want to have a short j105
    introduction
    um i will explain why and what and all
    that stuff don’t worry
    then i want to show
    how to test the test engine because if
    you want to start
    writing a test engine you should test
    your test engine
    uh that means you need to know how to
    start a test engine
    and after this we want to explore a
    little bit what is the minimum
    stuff you need to create a test engine
    itself
    um i will show you what is a
    minimum part to define a test or what
    what is the first step to
    to start with your domain specific
    language you want to have for
    creating tests or whatever then how to
    execute test plans and
    some ideas what you can do and the last
    part is more or less
    what i saw so far in the field or what
    i’ve done with test engines
    and this really leads mostly into a
    discussion about
    the whole topic so if you have any
    questions
    i will have a half eye on this chat
    but i can’t guarantee that i’m seeing it
    all the time so
    it may take some time to to read the
    question and keep an answer otherwise
    we will do it in the end so don’t worry
    about this one
    and well everybody knows jackhawk and if
    you’re not j frog you know that jeff
    rock has really cool t-shirts
    so you can win one and uh i think this
    time
    perfect for corporate time if if you
    have nothing to do to um at home or some
    kids you want to
    want to play with we have the traveler
    and have to this nintendo switch so just
    go to drivetrack.com
    show notes and here you see the link
    just go there i will share this later
    again
    so don’t worry about this one so the
    topic
    tests it’s an easy word short
    but it’s quite tricky if you’re looking
    at it so what
    what is part of a test so if if you’re
    looking at tests itself
    and to understand what a test engine
    should do or what a test engine have to
    manage
    it’s mostly you have this blue thing
    this subject to test so if you have
    whatever you want to test so i i don’t
    care right now
    if it is a cool java test it’s a web
    test if whatever test
    you have some preparations before the
    test because you you need some
    state then you want to run the test and
    then you have some clean up phase it
    means
    you have to do all the work to to make a
    clean environment again
    so that you can start with the next test
    and then you’re preparing the next stuff
    so that means that for every test you
    have this preparation and this clean up
    and this must be a very
    safe very robust operation so having
    mistakes or bikes or whatever they are
    this would be a
    beast to find but if you have a bunch of
    tests you have some kind of global
    preparation so
    what what could it be so if if you’re
    testing for example
    and you have a state you’re just ramping
    up data structure putting data in
    uh you have it you’re running a test
    you’re destroying this data structure
    that’s
    it but if you have some kind of web test
    it is
    more complicated because you want to
    ramp up resources you want to
    start a surface container database
    whatever
    it’s all the stuff you so you have some
    global preparations
    here i’m showing just two layers but
    have in mind that we have multiple
    layers so it is
    it’s just an antler thing so you can
    cascade it in a way
    that you have a quite complex structure
    and um yeah this this must be
    manageable so in a way that is reputable
    so if you want to run tests twice or two
    times
    you want to have exactly the same result
    and this is not trivial so there are a
    few things that’s
    that are not so easy to handle even if
    you have just
    easy piece of source code you want to
    test so
    but we’ll record this a little bit later
    so what what are the bad things here
    what what is the tricky part here
    if you’re looking at this one it
    implicitly means that you have
    some kind of context so if you have a
    preparation
    and you’re creating a data structure the
    first thing
    is that you need to know who is holding
    this instance this is instance holds for
    the instance it
    holds all the tests this is something
    that is hold by a contact that is
    outside of the text
    it’s around the test so what who’s
    holding who’s managing those resources
    right where
    it is and if you have this context have
    in mind
    that you can have there’s some bugs so
    even inside this context of this
    is part of the engine that is managing
    the context
    and with this um you have to think if if
    you want to go to
    concurrent tests how to isolate every
    single context against
    each other so with all complex things
    you
    want to have in mind so there is no
    limitation because with job you can do
    everything you can destroy it with
    offline stuff or whatever so it’s really
    up to you what you’re doing but your
    test engine must be able to channel this
    context in a in a performant way
    because if you are looking at this you
    see that
    the most stuff that you see here is just
    burning money the only thing that has a
    value
    in terms of money is that that you want
    to
    earn somehow is the subject to test
    this is the only part that is earning
    money all the other parts are just
    earning money
    that means you have to make sure that’s
    ramped up and run down it’s
    as fast as possible but the maintenance
    of this stuff is just
    as easy as possible so that’s this is
    maintainable
    over a long time and that
    this is not leading to more challenges
    than the test itself
    so and this you have again cascaded so
    you have it
    for test you have a test suite you have
    it a global preparation
    whatever and um
    here i i just
    i just say that i assume that everybody
    at this point
    or mostly it’s a symmetric thing so
    you have a ramp up and a corresponding
    ramp down but this is not always the
    case so there are situations where you
    have an asynchronous behavior
    and this will be tricky as long as you
    have this symmetric
    way of one went up one run down that’s
    corresponding to each other
    then the plane utilities you have or the
    the basic
    stuff that you have with jm5 is just
    good perfect so easy to enter how to
    deal with exceptions
    with exceptions it’s if it is an
    exception inside
    the test itself it’s not not the
    challenge but what
    is happening if you have exceptions
    during the
    preparations phase this is some kind of
    easy
    because if the preparation is failing
    the whole test is failing that’s easy
    so everything else is good but what
    happened if it’s
    failing during the cleanup phase so in a
    way that you’re not
    able to see it immediately or inside the
    context or in a leaky memory or whatever
    so this is not easy to to analyze and
    that’s not easy to
    uh to deal with even if you have long
    running tests
    and you have this uh very slow
    increasing memory usage or whatever so
    just have in mind that you have an eye
    on this one
    and one thing is if you have different
    tests you need a bunch of different
    preparations so
    make sure that or what what is a
    the trade-off between making it generic
    and making it specialized so this this
    is the basic ideas
    if you have now your with test groups or
    a bunch of tests for the global
    preparation you will have a bunch of
    test groups so for every test group you
    can scale so you can have
    as much as you want test groups
    whatever the name is tesui the test
    group whatever
    i don’t care about it you have just a
    bunch of groups and these groups have
    global progressions
    but the really cool thing with jmf 5 is
    that you have even a bunch of test
    engines so and that means you can
    have in one run multiple test engines
    that are running one after another i’m
    not talking about
    in which order they are running i’m not
    talking right now about how to activate
    deactivate them but
    in the end you can have from the idea a
    bunch of test engines
    that are running one after another so
    that means if you’re designing your test
    engine you have to think about
    what is going on before your test engine
    instance is running and what’s running
    and what’s happening
    after your test engine instance is
    running so
    um yeah well i
    i think this uh dealing with states is
    uh a typical thing in java
    so what we have so far so this picture
    i grabbed from the original
    documentation i think so thanks for this
    one to the j15
    and the first time i saw this this
    picture
    i thought yeah it’s easy so i i just
    jumped over it but then a little bit
    later i thought
    no there there are some tricky things in
    so for example the first thing is you
    have this old test you have this vintage
    engine on top of the platform so
    this is good so you have a platform the
    fundamental
    place for all your test engines and you
    will get at least
    two test engines with your installation
    of gmod5
    so if you are using it you have the
    vintage one you have the jupiter one
    the vintage one is for the old
    yeah you will see what’s going on if you
    have tricky beasts running with with
    rules and all this stuff and all this
    legacy
    some some things are running some things
    are running well
    and some parts well you have to work on
    but the good thing is if you can run
    multiple test
    engines you can think about
    migration about slow migration this is
    good because if if you’re creating
    at one time your own test engine you
    have to make sure
    that you can easily migrate to a another
    implementation or
    back to the generic one or whatever so
    migration is always a topic
    even even during testing testing is our
    production code
    and with this production code we are
    producing the production code for the
    customer so
    uh we should create test code like
    production code for the customer
    so it’s just our production code and
    that means i have to think and calculate
    in the same way so
    i have to think about how to maintain it
    how to get rid of it how to change it
    and so on
    so um talking about the old stuff and
    the platform
    then you have the engine this is a new
    fancy
    j105 environment everything is green and
    shiny right now
    and everybody’s happy to work with this
    one and then
    we have some kinds of use cases where we
    need or want to have
    third-party test engines we will go
    through this one later
    but um if i’m checking this one i
    i thought yeah it’s clear but then this
    bubble
    at the bottom this is this is something
    that yeah that was stealing some lights
    so you see that ides and build tools
    eclipse maven
    and so on they’re all running the
    platform
    and if you have in mind that something
    is invoking the platform
    and just thinking about oh there were
    they are
    dealing with reflections somehow in
    class parts and loading and all this
    stuff
    it turned out that in some situations
    it is a difference if you run your stuff
    in eclipse or in intellij so your test
    plan is slightly different
    or between maven and gradle so it
    depends on
    class parts on loading on how this stuff
    is done
    so if if something really weird is
    happening
    just try if you have the same results if
    you’re just switching between
    the ide or whatever just just as an idea
    so and if you’re building your own test
    engine you have to deal with some
    transporting
    class loading stuff later have in mind
    that your test engine will be invoked by
    a bunch of different tools maven gradle
    eclipse
    intellij macbeans whatever
    and make sure that everything that you
    are doing inside your test engine
    is as much as possible proposed against
    this
    tiny little changes in this class past
    universe
    and then i’m not talking about models
    and all that stuff this is just
    just more so
    j0.5 so we we have the subject to test
    as preparations
    and we have the global preparations and
    all this stuff so we have three
    parts with j5 that is
    defining more or less one test it is
    a test definition itself here it’s just
    a test
    then we will discover a little bit way
    how to extend this one
    how to customize this one and then we
    have the extension context itself
    so this three parts they are the main
    parts of this life cycle and the life
    cycle management so what’s going on the
    test and how long it takes
    and so on and this we have to understand
    and we have to
    learn what’s going on in the engine
    because this is the test engine we need
    later
    which is our test engine throughout this
    checkmark challenger
    i think it’s very familiar that test is
    just
    inside the class a method with the
    annotation at the test
    so it looks trivial right now but there
    are a lot of stuff we can customize if
    we want to
    create our own test later so here i
    assume
    that the test definition is always
    inside
    a class so a test is written as java
    code
    which is it’s not limited no limitation
    so you can define for your test engine
    test in a way
    whatever you want it mustn’t be sounds
    great just have reminded me creative so
    you can do a lot of stuff so it mustn’t
    be source code here i’m assuming that
    it’s just
    source code and in source word i have
    this notation add test well that’s it
    and uh we have some difference between
    trading and four and five so in terms of
    um must it be a public class or not it
    could be it mustn’t be a public
    class and it must be a public method so
    but
    this is just untactively chromium stuff
    here you
    can just read it in the documentation so
    i don’t want to go up here in detail
    but i want to customize it because if i
    want to write
    a test or if i want to create a state
    and clean up the state i need some
    possibility
    to extend the lifecycle to customize the
    lifecycle
    and the nice thing here in general five
    is that they
    handled it was more or less
    like like events you have the before
    each event after each event you have
    before all event and so on and every
    event
    is um represented by a functional
    interface
    so here you see i i want to create an
    extension
    that is manipulating the state before
    and after the test
    and then i have to implement two
    functional interfaces simply for
    each callback and the other integral
    there is some
    law of this lifecycle events just go to
    the documentation
    it’s a bunch of extensions or callbacks
    and then you can see what’s the order
    they are
    um they are thrown or invoked
    and so on but in the end you just have
    a regular class here i’m i’m just using
    it as inaccurate which is why
    this extension done static so but
    um you have this before each callback
    and for this you have to implement
    it before each method and then you have
    the after each callback
    and to activate your extension even if
    you have
    nothing in this extension it’s just
    using this
    extend with annotation class level or on
    the method level
    and then connect the class so
    my extension was the class you want to
    have associated with so
    here it stands with my extension at the
    class i want to have it so that’s the
    easiest and straightforward thing to
    extend now you have the possibility to
    do something in before each and you have
    something
    the possibility to do something after
    each so it means
    you will get this instant of extension
    context we will have a look at this a
    little bit later
    then you can do some code then the test
    will be invoked
    and then you have uh can do something
    that um
    is done after the test so far so good
    before we are dabbing a little bit into
    how to deal with this extension context
    and all this stuff i just want to see
    how i can deal with multiple extensions
    so this you need to know because if you
    have extension a and extension b
    there’s one interesting thing how to
    activate all of them
    how to combine them and what’s your
    order they are invoked
    so here if if you are doing it straight
    then you can just annotate
    your test class with all extensions you
    want to have
    and the next question is in which order
    they are invoked and this is different
    so if you’re writing
    extend with a and then extend with b
    it’s different to
    extend with b and then examples a so
    water matters
    so this is what you should have in mind
    and latest at this point
    it is clear that this way of extending a
    bunch of or
    to extended flowers with a bunch of
    extensions in this way it’s just not
    refactoring savings it’s just
    just a question of time that your
    colleague will do it slightly different
    it will be a disaster so it will just go
    wrong
    what’s done so far if you write it in
    this order first b
    then a it’s called from top
    to bottom so it will start with before
    all
    b then it will be called called the
    method from before all
    a then you will have before each way
    before each a
    then the test then after each a after hp
    after all a after all b and this is
    good so they’re going one two
    test to one bag so this is very
    symmetric and it makes it very easy to
    handle because
    if you have the rampable database first
    and then the software container
    it will be invoked in a different way so
    just destroy the circular container and
    then
    destroys the database so this is easy
    and straightforward and for the most
    uh things this is just the right way to
    go so it was a good decision to do it
    like this
    but sometimes it doesn’t fit that’s it
    but have it in mind
    so if you want to maybe
    it’s a good thing to just give a um
    a quick motivation uh for this
    it’s a good way if you want to extract
    it before like a method that you wrote
    before a before test and after test
    something that you know from junit4
    and you wanted to to apply it for let’s
    say 10 different tests but the same
    before
    before test and after test so this is
    coming
    so you can extract them so just people
    to have the motivation
    and why why would they even create that
    yeah okay this is more or less what’s
    coming up next so how to how to maintain
    this stuff
    so um but but the main thing is if if
    you start dealing
    with with life cycles or with
    preparations
    um some some developer um
    want to do it over inheritance
    traditional way so so i have my base
    test
    and then i’m extending my base test and
    then i’m going on the inheritance and
    this inheritance means that you can just
    inherit from one
    parent and so you have a linear list of
    inheritance
    and the other thing could be that you
    have a bunch of interfaces with
    stateless stuff
    and then you have a composite of these
    interfaces but both
    ways are not really what you want to
    have
    so too tool um if if you have a bigger
    project and you want to make sure that
    the surface container for example for
    this project is invoked always in
    some yeah in some way that you need it
    for for this uh project
    so you you would have one developer
    that’s creating this extension
    i’m ramping up our surface container so
    and here he assumed that the database
    already there and he assumed that after
    his preparation has done something
    whatever he is just focusing on
    how to ramp up the traffic container
    then what you can do you can
    write this extension you can make a jar
    out of it
    give it a version push it to your
    artifactory
    and use it somewhere so it’s just a
    regular piece of code and you extracted
    some kind of
    functionality so it’s just a
    decomposition of
    a big bunch of functions two
    tiny pieces atomic pieces so that you
    can compose them
    through more complex um pieces of code
    and if you want to compose it
    it’s more or less you have this atomic
    pieces and it’s really good advice to
    think
    in an extension that is more or less
    atomic so that you don’t
    think about what is coming before what’s
    coming after so it must be
    in the ideal world something independent
    and this is basic extensions
    mostly have this technical names like
    ramping up database ramping up
    software container whatever and the next
    level would be
    that you build a composition for example
    i have a
    web test a web test assumes in my
    project
    first database then servlet container
    and that means
    if you have a composite of extensions
    you start now with this those extensions
    so this
    that you annotate your um interface
    this annotation here with add extensions
    then you are adding all your extensions
    you wrote in the
    order you want to have them invoked and
    then you have
    one annotation you can use for your test
    so it means the wording in this
    piece of code is more domain specific
    and so basic extensions more technical
    so
    with every layer you’re adding you will
    have a more domain specific
    wording and then you have later for the
    developer just
    add web test at database test at
    whatever test
    or at customer whatever test so you can
    start
    building a complex hierarchy based on
    automatic thesis of extensions
    and the next thing is if if you know how
    to
    compose this hierarchy the next thing is
    who’s
    holding the instance you’re creating so
    for example if i’m creating
    an instance of my undertone or tomcat
    restoring this instance because if i
    have
    different if i have different tests
    running concurrently i need
    concurrent invocations of topcats of
    different
    tomcats i can create them with different
    ports or with test containers whatever
    and then who’s holding this instance um
    it’s it’s not recommended it’s highly
    not recommended to to have an attribute
    in your test class that is holding this
    instance
    because it’s not sure that you are using
    always the same instance of this test
    clause or it’s
    invoked several times or whatever so
    don’t don’t trust this one
    but there is this extension context
    since the extension context small is a
    hash map
    so you have this context and then you
    can grab out stores
    stores is just a naming schema and this
    name
    will give you a key value store and in
    this key value store
    you can put um the instance here i’m
    just putting a
    string in but you can put in the
    software containers and so
    you undertook and then storing it and
    inside the test you don’t have access to
    this extension context
    but just during this um callback phases
    so if you have before each and after
    each to get the same
    instance you’re just going to the same
    store
    with the same name here i’m just using
    the global one it’s not perfect but
    so you have to think about a scalable
    naming schema
    then you can say okay give me from the
    extension context the store i want to
    have
    and here is my instance i i want to deal
    with
    so and then you can run down during the
    test you don’t have access to this
    instance but you can use for example
    for instance that is running so
    um the next thing what you need
    sometimes
    is the possibility to inject something
    into your test
    because the extension context you don’t
    have access to this instance
    but if you want to have an in it during
    the lifecycle you want to create
    something and then you
    need this instance inside your test you
    have this injection mechanism
    and for this you need this
    parameter solver a parameter resolve is
    just an interface again and this has two
    methods
    supports paren here what you’re doing is
    just you
    define how to identify that this
    instance that should be injected
    is managed by this parameter solver
    for example here i’m just checking for
    an instance markers
    interface or whatever and then the
    method resolve parallel
    will be invoked after sports parameter
    and then you will get the same
    informations in parameter context or
    some context from the invocation itself
    and the extension context
    and then you can correct the information
    you need out of it and create an
    instance of whatever you want to have
    injected
    so this is a basic thing but um
    well for the details you need to read
    the documentation for sure and there are
    slightly a few difference between
    the you know versions of jln5 so i have
    make sure that you’re reading
    exactly the right documentation for your
    uh version you are using
    but this is more or less everything so
    you’re identifying the type you
    have the decision i’m responsible for
    and then you’re creating this stuff
    and here you can do everything there’s
    no limitation you can ask your database
    you can do whatever
    whatever magic in java is possible you
    can do here
    to activate this parameters over for
    example
    for method you can just extend with and
    then declaring the class
    so what you have right now is you can
    manage the life cycle with extensions
    now
    and you can get stuff injected from
    outside
    so with this you have a lot of tooling
    that will help you to
    test later your test engine or whatever
    your regular test
    so
    it means if if i want to write a custom
    test engine i’m writing a piece of code
    and this
    means if i’m doing tdd then
    i want to write a test from a test
    entrance so what i need for this one
    i need a way to test the new test engine
    and for this it’s highly recommended to
    use the jupyter engine
    because this is the best out of the box
    test engine you get
    so use this one to test your test engine
    and if your test engine is at some
    development stage that’s you say okay
    now i can test myself
    feel free to change but um the first
    recommendation is just
    go with this one what i want to have
    uh i want to first um see what what is
    the test import so for for this
    test engine the input is source code is
    a test class
    and i have here an example that is one
    positive test that has
    one the test two is just um
    throwing a runtime exception so it’s a
    failed one and the third one
    is disable test and now i want to check
    how i can
    test if the test engine is doing exactly
    what i’m expecting
    so for this you need a dependency in
    test scopes uh
    to jump platform test kit with the
    version you want to have or you are
    working with
    and again here i have one positive test
    one test so it’s failing and one that
    is just disabled and how to identify
    that the test engine is doing exactly
    what i’m expecting so how to test my
    test engine
    i have this class engine test kit
    and there’s this static method engine
    and here we will
    cover this later what an engine id is
    but i will give you the engine id from
    the test engine i want to
    test here it’s junit jupiter
    then i define what is the input for this
    test engine
    and here i’m using the selectors i have
    done static imports so if you’re dealing
    with reflection just
    check what what support utilities is
    part of this 2 unit
    um depends who you have already because
    they have done
    really good job with reflections so
    don’t write this stuff by yourself
    try try this one so and here what i’m
    doing is i’m selecting a class
    and i’m selecting exactly this class i
    defined before
    and that means this is my test input
    so and then i’m executing the whole
    stuff
    and i’m grabbing out the tests and then
    i start analyzing it with the search
    statistics and this means
    i check how many started how many
    succeeded how many skipped and how many
    failed
    and then you see okay two tests started
    one is disabled one was positive one was
    kept and one was failed so
    exactly what i’m expecting and this is a
    way how you should test your test engine
    later
    too so you have to define how to
    define a test and what you’re expecting
    and
    with this you start writing tests
    against your own test
    engine to make sure that the behavior is
    exactly what you
    want to have so uh
    this one
    yeah so yeah okay
    so now i want to test what’s what i will
    get out if i want to have the dedicated
    behavior or there’s a specific behavior
    of a test so if i’m just checking if the
    taste is good
    or bad it makes no sense so i need more
    information for example i want to
    analyze
    if this test two that’s failing is
    exactly failing in a way
    i’m expecting it and here i’m doing
    exactly the same so i have my test
    engine
    i’m selecting now the method of this
    class with the name test002
    this is not nice because it’s not
    refactoring safe so this string
    is not drawn to the method instance
    itself so that’s a weak point here but
    you’re defining one method so now i
    haven’t just input just one method
    and then i’m executing this one the
    first thing is i’m just checking okay
    this one failed
    exactly what i thought and then i can
    grab out the
    events and the characteristic this is
    detailed information
    so it’s finished with culture yes it’s
    um it wasn’t runtime exception yes and
    there was a message
    exactly with this one so you can check
    what kind of exception happened and if
    it is exactly the
    input or the the message of this
    exception with this you can test against
    villages
    i have this one so i can now test i can
    invoke a test engine
    i can uh define what’s the input of this
    test engine for this run and then i can
    analyze
    the results after a test engine run was
    successful
    so the next thing is how to get this
    test so a test
    engine should discover somehow the test
    then i prepare the launcher i’m creating
    a test plan
    which is what actually should be invoked
    in
    in some way and then i’m registering
    some some kind of listener i’d say
    they’re just collecting information
    during the run and then i’m executing
    everything and consuming
    the result so i’m not expecting that
    everybody is reading the whole source
    good and and remembering it so you have
    some slides uh go to
    drivewrap.com show notes or check on
    the internet so if the slides are
    available otherwise ask me
    and then you can go to this in detail
    what i want to show you is a
    general behavior of the general way to
    go
    so what you are creating first is a
    request so you’re selecting the input
    you want to have for this test for
    example here i’m selecting some package
    so what’s this request um this one i
    need
    and then i need instance of listeners
    listeners that are
    collecting information during the test
    run here i’m just using the summary
    generating listener the default one
    that’s
    part of this and the bad thing here is
    that
    uh so far i know you have to hold this
    instance because if you’re creating this
    instance and um using it during the
    creation of this configuration then
    you’re not getting
    the stuff out after after the test run
    is uh
    done so you have to hold this instance
    of the listeners
    then you’re building the configuration
    it’s um
    i highly recommend that you’re switching
    off all this auto registration and
    whatever stuff so that you have control
    what is activated and what’s deactivated
    then you’re creating one instance of
    your test engine and you see
    the jupiter test engine is just new
    constructors just
    creating instances so easy so no magic
    and then you’re combining those in the
    configuration and after this
    you’re just running it uh it means first
    you
    are discovering the discovering is this
    reflection magic that will build
    the test plan if you’re defining your
    test source good
    but feel free to build your test plan in
    any way
    you want to hack so it could be
    something completely different
    the only thing is you need some instance
    of a test plan that’s it
    then you’re executing the stuff and
    after this you’re grabbing
    the information out of your listeners
    from the test run
    all this is done you will have what’s
    next
    so the basic structure to create a test
    engine
    the absolute minimum is i don’t want to
    have a real test discovery i just want
    to have
    test engines that will be invoked and
    i just want to see if the test engine
    will be invoked by navy by the ide and
    so on this is the first uh
    useless test engine what i need so far
    is i need in compile scopes of juniper
    platform engine
    and then it’s a platform comments in
    compulsgate
    scope yeah and then
    yeah sure i’m not sure that i understand
    why do we need test engines at all
    test engines okay so why why why should
    i write my own test engine okay
    um the main thing is if you have
    if you have complex lifecycle for
    example and you want to
    um manage this one for example if if you
    have um
    every infrastructure that you want to
    run before the whole test plan is
    running so far i know you have to do it
    outside then you’re running the whole
    test plan and then you can ramp it up so
    your
    your life cycle is not managed by junit
    completely anymore
    and or you want to have something like a
    license check for example
    because you’re building a product or you
    want to have something like flaky tests
    or you want to have something like
    um uh what’s this called this
    um rotation test cover uh for example
    mutation test
    engine or you want to have this other
    test techniques or you want to create
    your own dsl
    you want to have something like a
    behavior driven or whatever
    domain specific language uh to give the
    possibility to create
    or to define tests so all this stuff
    you should start thinking about creating
    a test engine
    because the generic jupiter engine is
    good for the most cases
    but if you’re going to specific cases
    the the way to create all the stuff for
    example if you’re running
    web tests you have a complex life cycle
    you want to ramp up selenium nodes
    you’re dealing with stalker images and
    all this stuff
    and sometimes it’s easier if you’re
    writing your own test engine for example
    in this case
    and makes a whole lifecycle management
    easy
    or if you want to integrate in existing
    infrastructure
    you need to connect to other resources
    or you want to distribute tests for
    example i wrote a proof of concept for
    distributed test engine so that you’re
    collecting your stuff you’re pushing all
    this into a hazelcraft cluster executing
    it concurrently and then collecting the
    information so
    writing this one with a regular journal
    for jupiter engines just pane
    and then writing your own test engine is
    straightforward
    and sometimes yeah you have to decide at
    what
    complexity level you’re switching to
    your own test engine implementation
    i hope um this was a short
    short while um
    any other question to this one right now
    okay so um to write a test engine is not
    not so complex
    and sometimes really it’s easier as
    writing a complex life cycle with
    extensions
    um the only thing you have to do you
    have to implement the test engine and
    then you have exactly three methods to
    implement so
    get an id this unique id you need to
    identify this test engine
    you need to discover your tests here
    feel free to decide
    how to discover tesla if you want to
    consume a database to grab
    informations out of it to build a test
    plan against whatever
    if you want to read text files to create
    your test plan if you want to
    whatever you are thinking about here is
    the right place to
    to identify how to create a test plan
    and then there’s this execution phase
    just
    you have your test plan and now you’re
    going recursively to all childs
    in this tree inside your test
    descriptor or your test tree and
    executing this one
    so this is small is the basic what you
    need
    and um yeah that’s that’s
    let’s go to to this one if if you have
    done exactly this one so for example
    here i’m just
    um giving you an idea whatever you need
    i just me
    taking the simple name then i’m creating
    exactly one node so root node
    for my test plane with no test in it so
    i’ll just write down it
    and then what i’m doing in the execution
    phase is just for my request i’m
    grabbing the root
    the test descriptor from my my start
    point
    and then i’m grabbing all listeners out
    of it i’m
    executing this stuff so i say okay now i
    start executing my test
    i’m going to the engine grabbing all
    children out of it
    going to every children saying to my
    listener whatever listener you want to
    have here just have this execution
    listener
    say okay i start executing i’m finishing
    successful or failed it depends what
    what is the result of it here i’m just
    saying successful
    and after this i’m just saying okay i’m
    done so we’re going recursively this
    tree down
    and collecting the information about
    every single test he has no tests so we
    have just a
    success going to the root node and
    that’s it
    so with this yeah yeah
    sure um maybe i’m misunderstanding where
    is the test actually run
    the test is running we will come to this
    with the next
    next um test engine this is just a whole
    thing but
    during the execution during during the
    time the execute method
    will be invoked you’re going to all test
    nodes it’s a tree
    and then you have different kinds you
    have container tree nodes and you have
    test tree nodes and if you are
    going to the test node or if you have a
    test node
    you will have all the information you
    collected during the discovery process
    for example class what method what
    whatever date time
    whatever you need and then you have the
    possibility to say
    execute now and this is the place where
    you’re
    actually really executing the test
    itself
    okay yeah we will come exactly to this
    one so
    um so if if you’re just going off the
    root note with no test inside
    you will get already the whole support
    that you see i have one container
    started one was successful so
    it’s it’s running so you can use maven
    already if
    you activate it i will show it how to
    activate it but this is
    just a valid test entry it’s not testing
    it’s completely useless but
    so how to define your own tests so for
    example that you can vote i have my
    manual test my vardy test my databases
    whatever
    for your own test engine so we have to
    create an annotation
    then we are executing all uh we want to
    discover all tests we annotated with
    this normal test
    and then we execute it and what i want
    to have is next is that the ide is
    supporting it and maven is supporting it
    and then you have more or less
    everything you need at this point
    to build this marker you have just to
    create an annotation with
    target on a method for example if you
    want to have it or method if you want to
    have it a method in
    class then you’re just using element
    type method and
    clause this is good if you want to make
    sure that some annotations with
    information’s insights annotation is
    just used on a class level because you
    want to have this one
    for init processes and some others just
    on a test method level
    so that you’re not mixing up attributes
    for example for global preparation and
    for local preparation or whatever
    the only thing is that you’d really need
    is a retention policy runtime
    well otherwise you can’t grab this stuff
    out with reflecting later
    and there’s one thing called testable
    and this is the only thing you really
    um have to understand why this is there
    we call this testable so here i’m doing
    this one here for example for the
    target on class i want to have one
    iteration that is just
    for initial class level and this one was
    just for init on
    method level if you want to divide it
    it’s up to you but the only thing that
    is a little bit magic this is testation
    and testable is more or less they um
    i think it was coming from jet brain so
    they they needn’t the ide
    needs a possibility to identify what
    annotation
    is actually a test annotation to support
    it
    and you’re completely free your there is
    no inheritance or whatever
    so you need some kind of identification
    and then they defined
    you have this this annotation test able
    and the ide vendors are listening or
    checking for testable
    and if they found this interface on this
    annotation
    they will treat this interface like a
    test language unit and
    test annotation but then for your
    present
    so that is why you need this a test
    table so that your id is supporting it
    and after this it’s all ready so
    to have this runner engine just a new id
    because we have a new engine
    and the main thing is you have to define
    what is a test class
    or test method uh for this
    here’s a part where you can define the
    syntactical behavior of it
    so how to define the test so you can say
    i’m not supporting extra classes i’m not
    supporting
    private classes and i’m not and i want
    to have
    explicit annotation nano test class so
    then i will check if
    i have for example some some other
    attributes so here you’re defining what
    is a minimum requirement so that it will
    be treated as a test class
    so i extracted here this one just as a
    predicate
    because we need it later so everything
    you need to define
    plus the annotation that is um
    the marker for your test class if you
    have this for test methods
    for example you can say okay i’m just
    executing it is
    not static if it is not private if it is
    not abstract
    if i have a param count that is exactly
    zero
    or you can say okay i want to have at
    least the param
    of type a or of type b so here
    you are defining the syntactical stuff
    how to define a test and this is more or
    less
    the the first step to define your
    requirements
    for the test environment if you want to
    make sure that every test method will
    have an inject at
    whatever test class or report or
    whatever
    here’s the right place to make sure it
    is just grabbing this one
    then annotated with number test okay
    it’s a test method
    and you can define if you want to have
    some kind of return type
    for example if you want to have
    statistics or some kind of return
    from every test method because you just
    want to have it for whatever
    then you can define here okay a test
    method must have a return type
    a or b or whatever so here you can
    define everything you need again
    just a predicate we need it later during
    the discovery process
    the discovery will give you four entry
    levels and this is a little bit tricky
    if you’re doing it the first time you’re
    you’re just going here a little bit mad
    and i’m not sure if it is already
    changed but you have to
    write copy paste this boilerplate code
    by yourself it’s
    it’s just pain i hope they will change
    it but it’s always the same so
    what you’re doing is you have this
    classplus root selector this package
    selectors is class select and method
    selector
    and here’s the change so if you’re
    running with maven for example on a
    package
    then you will get a package selector if
    you’re using exactly the same with right
    click on
    intellij you will get a class plus root
    selector
    with a filter so you have to implement
    all these
    four ways to uh
    to work or to deal with the selectors
    otherwise
    the behavior is slightly different or
    some something is just not working
    but in the end what’s what’s going on
    here is just
    you’re going recursively from this part
    here
    you’re in through all entities you have
    you’re cropping every single class
    going in every single class to every
    single method and checking with your
    predicates if it is a test class and if
    it is a test class if this is a test
    method you want to support
    so this is what’s going on here um which
    is a bunch of code it’s just going
    recursively down so
    okay if you have a class check if it is
    a test class
    and then append
    all methods toward the next test level
    and so on so and if you have
    uh found something we’re creating a
    descriptor
    and the descriptor you will see the
    implementation
    it’s more or less uh right let’s see
    here the descriptor
    is the node inside the test plan and
    this is a place where you hold all the
    information
    that you need during the run time during
    the test execution
    so you’re collecting here in this
    container nodes for this
    root node for example the class name the
    method name
    and some whatever input
    so these are the descriptors
    and then you are going to checking class
    going over it creating this descriptor
    and so on
    so the main thing is you’re going
    recursively
    through all class passes we have just to
    a package
    just for class or just checking that
    method
    using the reflector you tilt from the
    jail to 15 because this is making this
    work
    really easy and then what you want to
    have is more or less
    this test plan make a tree out of it
    please no graphs
    and then you have two nodes you have a
    type container and type test
    why you can have a test in a container
    at the same time i don’t have that’s
    possible
    mostly easy it’s just hold everything in
    a container or a root a node
    should be always a container until there
    are child
    children and the children the last one
    should be a test it’s the easiest way to
    to define it and then have a look at
    this abstract test descriptor
    and don’t implement the interface
    because there’s a bunch of work already
    done
    so you can go there as well so
    how to deal with this what you can do
    not much but you can what you can do if
    you’re on a class level and
    classes are the definition to define
    tests
    if you have a class test descriptor what
    you can do you can
    go from here recursively down for
    example
    finding all methods in this test class
    checking if it is a valid test method
    then just creating the next test
    descriptor and adding this one so it’s
    just a recursive way
    so make sure that you’re giving back the
    type
    it’s the last line here type container
    type test
    so that later during the execution phase
    it could be
    identified right
    so um coming now to to the information
    you have during the execution phase so
    the last thing uh the children for
    example the last children in the street
    um is the last night we’ll have all this
    information here i’m just collecting the
    test class and the test method that
    would
    that is identified if you have inside
    your annotation some
    some information like an attribute
    inside your annotation it would be
    good during the discovery process to
    extract this value and store it
    in this test descriptor as well because
    this one will be used
    during the execution a little bit later
    so here is the right place to store all
    the information you need
    for the test that is static and not
    requested
    during the execution the executor itself
    so now if if you want to execute it so
    it’s just
    it depends on the level you are if
    you’re on the root note the engine
    descriptor just say
    okay execute this container start with
    recursive going down
    the next one we have class descriptors
    if it is a class descriptor just say
    execute this container it’s nothing else
    that’s going one step down
    and then the last one if it is a test
    method test descriptor
    we’re actually executing the stuff means
    in containers just i will say to my
    listener
    i’m getting out of this request and say
    i will start working on this level
    then i’m going to all children and
    execute them
    and if nothing is happening i will say
    i’m execute i’m finished i’m done and
    i’m positive or negative
    so this you are doing for every layer if
    you have three layers in your tree
    we’re doing this for two layers and the
    last one will be
    the execution method and here again i’m
    now on method level
    i start execution i’m executing the test
    method and i’m giving back the results
    the test execution result
    so after we have done all this
    repetitive work
    really copy paste your stuff it’s really
    don’t write it by itself
    then we’re coming to the final execution
    of the test
    and that means i have this method test
    descriptor whatever your name of the
    test descriptor is
    everything inside this descriptor is now
    usable for the execution
    plus everything you can request now and
    then
    what you are what i’m doing here is i’m
    just using the reflecting video to
    create
    this test class i’m invoking
    by reflection this single method and if
    no
    exception is happening i assume it’s
    right and giving back
    successful if there’s any kind of
    exception i’m just saying
    it’s failed that’s it if you need
    technology here in this one like
    cdi like whatever it’s the right way
    here to get all this technical
    infrastructure to execute your test
    but this is the main thing so here you
    can do everything that java is learning
    and just do whatever you want the main
    thing is something is happening
    it’s failed if everything’s right the
    feedback is successful
    that’s it so now you are able to write
    the whole
    engine in a little bit more compact way
    so getting an id
    you have the two ways to define if it is
    a test class or a test method
    here with this predicates then you’re
    going down
    building up the test plan during the
    discovery process
    and the execution is just going over
    this test plan
    and executing every single test inside
    this hierarchy
    that’s it and you’re collecting
    information when does it mean that the
    platform is very very
    thin layer uh yeah
    it’s just a little bit called java so
    the platform itself is just
    just a few methods it depends so it
    really depends so how to create
    so one one tricky thing is how to create
    your test plan if you’re just going over
    source code
    you’re just scanning your classpaths
    identifying the methods collecting them
    from
    that’s it if you have a test engine that
    is combining different resources for
    example
    at this date on this machine with this
    class path
    and whatever this configuration this
    creation of a task plan is more or less
    work and the next work
    that should be done is execution itself
    there’s just a bunch of software that
    will be executed so
    it’s a test so most people just thinking
    that
    uh a test plan should be just defined in
    in source code but it’s not
    it’s not a limitation so be creative
    here because then you have the full
    potential of this test engine
    so that you have the wrapper to execute
    all the stuff
    the next thing is how to activate this
    one
    it’s just uh service locator here or
    unit platform engine test engine
    and then you’re just writing the class
    name in it
    and what you achieve now is you can now
    take a class using edna test class
    on the class level and nano tests on the
    test level
    and you have full ide support now you
    have full maven and gradle support noise
    so it’s it’s done so you have now a
    complete independent test engine
    that you can just wrap in a jar making a
    version out of it
    and let your team use it
    why why or what can you do with this
    test classes
    so for example if you have a commercial
    product and you want to have something
    like license check you can do it inside
    your test engine
    on the other side if you have license
    checks because you are consuming
    expensive resources then you can do it
    inside your test engine this
    authentication
    authorization process can be done inside
    this test engine
    um ramping up some specific
    infrastructure
    checking against uh limitations
    something like a
    failed break or some whatever whatever
    you want to have you can
    add in this test engine that is helping
    you to manage the life cycle
    and to make the usage of the test
    itself easy the main specific test
    definition
    so if you want to have something like
    behavior driven tesla whatever
    some other way of defining test it’s
    up to you to define the syntactical
    environment you want to use
    to define a test plan you can use
    this um test engine for dynamic test
    input of external resources for example
    if you are not able to write it in code
    java because you have to ask during the
    time of the execution some external
    system to get some
    stuff out a similar test engine would be
    a good place
    uh compared to extensions if you have
    different tech
    testing techniques like mutation testing
    or
    property based testing or random monkey
    testing
    or whatever statistic you want to use
    for your testing or
    security payload testing problem all the
    stuff you you can use
    and dedicate a test engine for it that
    is specialized for this
    so that you don’t have to build with
    generic tooling
    this behavior this is mostly easier one
    thing is you can create persistent
    immutable test plans
    if you’re creating test plans and you’re
    doing it twice
    and you’re doing it once was maven once
    was uh intelligent
    it could be that the test plan is some
    kind of
    different it depends on how to create
    the set plan and it depends
    what are the the weak points here like
    reflection or ordering or sorting or
    whatever
    if you want to have immutable test plans
    because you want to have this
    test plan stored with build information
    so that
    everything is reproducible even the test
    line here’s a good place to go
    because you have the test plan and you
    can store it in a way
    that you can share it rerun it exactly
    in the same way
    what you can have for example is like
    something like test execution priorities
    based on the usage on external resources
    or your own resources you can prioritize
    tests on different machines on different
    nodes whatever
    because you can interact with
    distributed system for example if you’re
    spreading it over hazel cars cluster or
    if you are going to whatever system
    so you can do a lot of stuff that is
    complicated with regular extensions
    and complex lifecycle be sure if you
    have a complex life cycle have a look at
    this one
    for example this i mentioned already so
    if you have for example
    the need for for distributed uh test
    execution
    then uh this could be one thing for test
    engines just grabbing the classes
    pushing it to a distributed class loader
    to distribute
    uh distributed execution nodes run the
    stuff there
    grabbing it back i have done it for
    example with uh testing
    um vardy nabs because vardin itself and
    the web tests
    with ramping up selenium and stuff and
    databasing it was low
    so i just scaled horizontally because
    the chest itself is slow so i’m scaling
    horizontally and
    this was easy to always for example yes
    because so
    inside your test engine um
    yeah then security payloading is one
    thing you should have in mind for
    example
    if you want to have security payloads
    for for your um
    apis or whatever then you could do it
    like uh you have a repository you’re
    asking for the binaries
    for the immutable you’re creating this
    pass plan you’re injecting this stuff
    and the test result will be distributed
    for example in external reporting
    systems
    or on whatever so it’s
    really if you have those complex life
    cycles and need for documentation all
    the stuff
    and custom test engineers is pure gold
    for it
    because you can customize for example
    auditing systems and all this stuff or
    um creating a runtime metrics uh to to
    see how much time you have burning on
    every single machine
    and so this one okay well
    if if you’re spawning new nodes with
    your test engine with stalker or
    uh loading dynamically stuff uh it’s
    perfect if you’re using out factory with
    z3 to scan on the flight because we have
    this rest api
    and during the execution you can
    provision the whole environment so you
    can say
    i want to have for every single test
    step a dedicated repository i’m using
    if one test is failing so one step of my
    test pipeline
    is failing i’m holding all states until
    this one and i’m just
    re-running the latest step of my test
    pipeline
    so i’m not doing all this stuff again
    and again so you’re killing rebuilds
    with this
    so this is one one interesting thing and
    we have some license check and all this
    stuff
    um yeah well so more or less i’m
    from the technical point of view on i’m
    done with the test engines i hope i
    could give some ideas what you can do
    with this one
    for sure you can try this for free check
    the website there’s some some
    interesting news
    so just just as a heads up and
    um well i’m open for questions now
    if someone has some experience or
    some questions or some ideas it would be
    just the right right time to to ask
    too far away well
    the main thing is um
    just right if you want to have this
    code the boring part was the discovery
    just let me know
    i have this demo somewhere on github i
    think already
    so that you can just start with ramping
    up your own test node
    and then playing around with this stuff
    um
    yeah you can do it with every everything
    that’s running more or less on the jvm
    so with scrolling or whatever
    um then can i have a small question
    sure do you have some recommendation of
    a migration strategy between
    jet unit four and five
    documentation well not really
    documentation
    i i just know that i i only know that
    mostly
    people have trouble with with his rules
    so how to migrate this so everything
    that is inside the life cycle
    that is more or less a pain so
    if this is complex and then for example
    if you have to
    to rebuild this life cycle then
    sometimes
    it’s really it’s a good thing to um to
    have an
    own test engine but then you can rebuild
    this lifecycle
    without doing this stuff or you can
    check for example if if you want to have
    some special support for this
    but that’s the only thing i know so
    migrating if if you’re not able to run
    it with a vintage
    engine inside your junit 5 platform
    and you really have to migrate this
    stuff
    well you have to check how much code you
    really want or if it is just running
    this
    vintage engine okay thank you
    yeah okay
    hello so anybody has a
    maybe a general purpose question
    on journey five it’s a maybe a good time
    to ask
    well the easiest thing is really the
    documentation is not bad for the for the
    course stuff so
    just start writing your first test
    um going in detail um
    if if you start writing extensions don’t
    do the mistake and
    and uh hold instance by yourself really
    go over the extension context do it
    um so i swore too too often don’t go
    over inheritance
    don’t do it so i have to do it like make
    sense i said that’s also a really
    overall
    composition of extensions
    um otherwise it’s a very
    very straightforward thing sometimes a
    little bit tricky
    if you need for example this parameter
    server to create a
    dynamic range of input values so they
    have this uh
    important cvs or whatever stuff but if
    you really
    want to read the config based on this
    config and the environment variable for
    example
    oh i’m on a windows machine and now i
    want to create this web driver and
    another web driver
    so stuff like this this is um it’s not
    so handsome
    with core extensions so yeah
    so if if you’re on this level then then
    think about how to manage this lifecycle
    even even
    then later it’s not symmetric for
    example you have
    what’s the right time to create a web
    driver if you have a bunch of web
    drivers what you are doing with web
    drivers if one test is failing because
    then the whole test
    execution is just killed so all this
    stuff so
    then then think about some convenience
    with your own test engine
    it makes your life really easier
    so it seems that the real meat here is
    inside the
    um the engine themselves so jmd4 as we
    know it is
    everything essentially is inside the
    vintage
    implementation of the test engine right
    so the platform seems really really
    thin yeah it’s just execution of a test
    engine and this is
    executing three methods more or less
    that’s it
    so idea discovery execute that’s it so
    this is a
    thin layer uh what’s really good
    is this reflection stuff they say build
    so i really recommend you
    to have a look at this one because
    there’s a lot of work done inside the
    shoe reflection rituals
    um but give it a try
    so if you have your blueprint for test
    engine it’s just
    a template project and then defining
    your new syntax because
    the boring part is the discovery if
    you’re just going over classes
    then the discovery process is always the
    same maybe they extracted it now for
    with a
    better extra class what you never should
    do
    my personal experience maybe i’m wrong
    but what you never should do
    based on my experience is extending the
    jupiter
    engine don’t do this one this just
    no don’t do it so um
    everything you are not able to do with
    extension towards your own test engine
    but don’t extend the
    or inherit from from the jupiter engine
    it’s too complex
    i wouldn’t do it
    there are the ones just tried it’s
    really easy
    sorry any more questions
    oh quite i saw here some some some
    questions on slack
    some corrections from chris uh uh not
    reflective utils it’s called reflection
    support
    sorry for this so whatever
    reflection supported there use it from
    the gl5 team
    don’t write it by yourself that’s the
    main message i want to say
    anybody else has a question about unit 5
    you want to ask
    oh yes a simple way to migrate in place
    from james to jm5
    simple way of migrating the test itself
    mostly mostly it really depends on
    how complex you have done your chair
    your neck force off so if this was
    good and maintainable written not too
    freaky in terms of inheritance and
    mixing up stuff
    it will be easy it’s it’s just a regular
    prefecturing project so it’s it’s like
    it’s your production code it’s it’s the
    same as as you have done for your
    customers so
    um mostly the pain mostly is that this
    source code base for 2004 project if you
    have a legacy project it’s
    so old that you have a huge amount of
    layers inside this one
    and to get rid of this you really have
    to
    to define if if you want to rewrite it
    or if you want to migrate it so
    um but what you should do
    if so what i personally do is
    if i want to migrate i’m just
    creating not the line coverage i’m
    creating the notation test coverage
    because this is a way stronger coverage
    and try to increase the existing test
    environment
    the mutation test coverage and then
    migrating because this is a
    there’s a stronger one compared to line
    coverage i have a talk on on youtube
    about mutation test coverage or i can
    give it here again so
    um feel free to check this one out
    because mutation test coverage is really
    it’s a strong thing um
    the context of the maiden face because
    in a mixed mode it doesn’t run in
    parallel so much but in a negative force
    for say just jam private runs okay
    yeah so there is from from chris is a
    one-on-one implementation so i’m not
    using this surefire whatever plugin i’m
    using this one
    from uh accuracy so um
    because this makes my life very easy so
    but i can can
    check the link to the github repository
    and share it
    so i’m not using file save and and show
    fire anymore i’m just using this one
    it’s tiny it’s fast ah here already
    here’s the unit platform maven plugin
    we’ve posted it in the chat already so
    this i’m using introduction now and
    it’s it’s solving a bunch of
    challenges i had especially with show
    fire
    so um otherwise concurrent execution is
    always a pain if you’re not clear with
    states so it’s
    like regular code and um
    i think enjoy unit 4 a bunch of stuff
    must be static and this is painful and
    this is
    just not existing in general 4×5
    but um
    as far as i understood it right there’s
    no guarantee
    how often an instance of a test class
    will be created so if you have three
    tests inside this test instance
    it’s not guaranteed that it’s just
    invoked once and then
    uh invoking all three test methods or
    it’s
    in uh creating for every test invocation
    anyways and so
    there’s no guarantee it means you have
    to make sure that every single test
    and is perfectly just atomic
    sorry and it means don’t don’t do
    aesthetic in all that stuff so
    it’s just regular if you have to deal
    with concurrent
    immutability concurrent uh stuff no no
    static don’t don’t use barrier legend
    whatever stuff
    so
    okay we have a question in the chat
    for mark and you can see it and second
    for blast
    um i think i saw something
    so i’m not really sure but what you
    should do is this
    pioneer project so everything that’s not
    going into the core j155 project is
    collected in this pioneer project
    and um i think they have a list of
    already known
    test engine custom test engines so have
    a look there
    but i personally never have never used
    it so i can’t say yes or no
    i see create chris answers that octo
    will be 100
    running on the jrd platform okay cool
    dude
    oh okay so when if there are
    no more question then i think it was
    very
    very knowledgeable as well
    thanks a lot thanks a lot for sharing
    this information
    i think it’s sometimes a it seems a lot
    of information but it gives the people a
    spark spark ideas that sometimes you
    know
    get cooked in your brain and you use
    them later
    yeah so that sort of gives a really good
    ideas so thanks a lot for sharing
    and then and for the community we’re
    going to see you we have a
    next in september we have two lectures
    and
    also seem quite interesting so hope to
    see you all
    in september lectures