Thanks for joining the discussion Qingsheng. In general, I am not opposed to upgrading our testing library to JUnit 5. Also, the idea of starting with individual modules and do it incrementally sounds reasonable.
However, before starting to do it like this, the community should agree that we want to replace JUnit 4 with JUnit 5 eventually. This does not mean to rewrite all existing tests to use JUnit 5 but at least the default for all new tests should be JUnit 5 at some point. Otherwise, I fear that we will fragment the project into modules that use JUnit 5 and those that use JUnit 4. If this happens then it becomes harder for people to work on the code base because they always need to know which testing library to use in which module. Cheers, Till On Tue, May 25, 2021 at 8:53 AM Qingsheng Ren <renqs...@gmail.com> wrote: > Hi forks, > > I’d like to resume the discussion on migrating to JUnit 5. I’ve been > working on a connector testing framework and recently have an exploration > on JUnit 5. I think some features are very helpful for the development of > the testing framework: > > • Extensions > > JUnit 5 introduces a new Extension model, which provide a pluggable > mechanism for extending test classes, like managing test lifecycles and > providing parameters. Also with the help of extension, we can get rid of > some limitations introduced by class inheritance, like current TestLogger & > KafkaTestBase. In testing framework this is helpful for handling the > lifecycle of Flink cluster and external system. > > • Annotations > > JUnit 5 provides better support in annotations, working together with > extensions. We can simple mark types/fields/methods in the test, then let > extension to search these elements and manage their lifecycle in the test. > For example test with annotation @MiniCluster will be provided with a > lifecycle-managed MiniCluster automatically. > > • Parameterized tests > > JUnit 5 supports more powerful parameterized tests. Testing framework uses > this to inject different test environments and external contexts into the > same test case, to run the case under different scenarios. > > So I think JUnit 5 is quite flexible for developing such a framework or > test utility based on it. My suggestion is that we can take connector > testing framework as a starting point of using JUnit 5, then we can expand > our exploration to more modules, finally dive into the entire project. > > -- > Best Regards, > > Qingsheng Ren > Email: renqs...@gmail.com > On Dec 1, 2020, 4:54 PM +0800, Khachatryan Roman , wrote: > > +1 for the migration > > > > (I agree with Dawid, for me the most important benefit is better support > of > > parameterized tests). > > > > Regards, > > Roman > > > > > > On Mon, Nov 30, 2020 at 9:42 PM Arvid Heise <ar...@ververica.com> wrote: > > > > > Hi Till, > > > > > > immediate benefit would be mostly nested tests for a better test > structure > > > and new parameterized tests for less clutter (often test functionality > is > > > split into parameterized test and non-parameterized test because of > JUnit4 > > > limitation). Additionally, having Java8 lambdas to perform fine-grain > > > exception handling would make all related tests more readable (@Test > only > > > allows one exception per test method, while in reality we often have > more > > > exceptions / more fine grain assertions and need to resort to > try-catch -- > > > yuck!). The extension mechanism would also make the mini cluster much > > > easier to use: we often have to start the cluster manually because of > > > test-specific configuration, which can be easily avoided in JUnit5. > > > > > > In the medium and long-term, I'd also like to use the modular > > > infrastructure and improved parallelization. The former would allow us > > > better to implement cross-cutting features like TestLogger (why do we > need > > > to extend that manually in every test?). The latter is more relevant > for > > > the next push on CI, which would be especially interesting with e2e > being > > > available in Java. > > > > > > On Mon, Nov 30, 2020 at 2:07 PM Dawid Wysakowicz < > dwysakow...@apache.org> > > > wrote: > > > > > > > Hi all, > > > > > > > > Just wanted to express my support for the idea. I did miss certain > > > > features of JUnit 5 already, an important one being much better > support > > > > for parameterized tests. > > > > > > > > Best, > > > > > > > > Dawid > > > > > > > > On 30/11/2020 13:50, Arvid Heise wrote: > > > > > Hi Chesnay, > > > > > > > > > > The vintage runner supports the old annotations, so we don't have > to > > > > change > > > > > them in the first step. > > > > > > > > > > The only thing that we need to change are all rules that do not > extend > > > > > ExternalResource (e.g., TestWatcher used in TestLogger). This > change > > > > needs > > > > > to be done swiftly as this affects the shared infrastructure as you > > > have > > > > > mentioned. > > > > > > > > > > Only afterwards, we start to actually migrate the individual tests. > > > That > > > > > can be done module by module or as we go. I actually found a nice > > > article > > > > > that leverages the migration assist of IntelliJ [1]. > > > > > > > > > > As the last stop, we remove the vintage runner - all JUnit4 tests > have > > > > been > > > > > migrated and new tests cannot use old annotation etc. anymore. > > > > > > > > > > [1] > > > > > > > > > > > > > https://blog.jetbrains.com/idea/2020/08/migrating-from-junit-4-to-junit-5/ > > > > > > > > > > On Mon, Nov 30, 2020 at 1:32 PM Chesnay Schepler < > ches...@apache.org> > > > > wrote: > > > > > > > > > > > I presume we cannot do the migration module-wise due to shared > test > > > > > > utilities that rely on JUnit interfaces? > > > > > > > > > > > > On 11/30/2020 1:30 PM, Chesnay Schepler wrote: > > > > > > > Is it feasible that 2 people can do the migration within a > short > > > > > > > time-frame (say, a week)? > > > > > > > Must the migration of a test be done in one go, or can we for > example > > > > > > > first rename all the Before/After annotations and then to the > rest? > > > > > > > Are there any issues with other test dependencies (i.e., > hamcrest, > > > > > > > powermock (PowerMockRunner), mockito) that we should be aware > of? > > > > > > > > > > > > > > I generally like the idea of using JUnit 5, but am wary of this > > > > > > > migration dragging on for too long. > > > > > > > > > > > > > > On 11/27/2020 3:29 PM, Arvid Heise wrote: > > > > > > > > Dear devs, > > > > > > > > > > > > > > > > I'd like to start a discussion to migrate to a higher JUnit > version. > > > > > > > > > > > > > > > > The main motivations are: > > > > > > > > - Making full use of Java 8 Lambdas for writing easier to > read tests > > > > > > > > and a > > > > > > > > better performing way of composing failure messages. > > > > > > > > - Improved test structures with nested and dynamic tests. > > > > > > > > - Much better support for parameterized tests to avoid > separating > > > > > > > > parameterized and non-parameterized parts into different test > > > classes. > > > > > > > > - Composable dependencies and better hooks for advanced use > cases > > > > > > > > (TestLogger). > > > > > > > > - Better exception verification > > > > > > > > - More current infrastructure > > > > > > > > - Better parallelizable > > > > > > > > > > > > > > > > Why now? > > > > > > > > - JUnit5 is now mature enough to consider it for such a > complex > > > > project > > > > > > > > - We are porting more and more e2e tests to JUnit and it > would be a > > > > > > > > pity to > > > > > > > > do all the work twice (okay some already has been done and > would > > > > > > > > result in > > > > > > > > adjustments, but the sooner we migrate, the less needs to be > touched > > > > > > > > twice) > > > > > > > > > > > > > > > > Why JUnit5? > > > > > > > > There are other interesting alternatives, such as TestNG. > I'm happy > > > > > > > > to hear > > > > > > > > specific alternatives. For now, I'd like to focus on JUnit4 > for an > > > > > > > > easier > > > > > > > > migration path. > > > > > > > > > > > > > > > > Please discuss if you would also be interested in moving > onward. To > > > > get > > > > > > > > some overview, I'd like to see some informal +1 for the > options: > > > > > > > > > > > > > > > > [ ] Stick to JUnit4 for the time being > > > > > > > > [ ] Move to JUnit5 (see migration path below) > > > > > > > > [ ] Alternative idea + advantages over JUnit5 + some very > rough > > > > > > > > migration > > > > > > > > path > > > > > > > > > > > > > > > > --- > > > > > > > > > > > > > > > > Migrating from JUnit4 to JUnit5 can be done in some steps, > so that > > > we > > > > > > > > can > > > > > > > > gradually move from JUnit4 to JUnit5. > > > > > > > > > > > > > > > > 0. (There is a way to use JUnit4 + 5 at the same time in a > project - > > > > > > > > you'd > > > > > > > > use a specific JUnit4 runner to execute JUnit5. I'd like to > skip > > > this > > > > > > > > step > > > > > > > > as it would slow down migration significantly) > > > > > > > > 1. Use JUnit5 with vintage runner. JUnit4 tests run mostly > out of > > > the > > > > > > > > box. > > > > > > > > The most important difference is that only 3 base rules are > > > supported > > > > > > > > and > > > > > > > > the remainder needs to be migrated. Luckily, most of our > rules > > > derive > > > > > > > > from > > > > > > > > the supported ExternalResource. So in this step, we would > need to > > > > > > > > migrate > > > > > > > > the rules. > > > > > > > > 2. Implement new tests in JUnit5. > > > > > > > > 3. Soft-migrate old tests in JUnit5. This is mostly a > renaming of > > > > > > > > annotation (@Before -> @BeforeEach, etc.). Adjust > parameterized > > > tests > > > > > > > > (~400), replace rule usages (~670) with extensions, exception > > > handling > > > > > > > > (~1600 tests), and timeouts (~200). This can be done on a > test class > > > > by > > > > > > > > test class base and there is no hurry. > > > > > > > > 4. Remove vintage runner, once most tests are migrated by > doing a > > > > final > > > > > > > > push for lesser used modules. > > > > > > > > > > > > > > > > Let me know what you think and I'm happy to answer all > questions. > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > -- > > > > > > Arvid Heise | Senior Java Developer > > > > > > <https://www.ververica.com/> > > > > > > Follow us @VervericaData > > > > > > -- > > > > > > Join Flink Forward <https://flink-forward.org/> - The Apache Flink > > > Conference > > > > > > Stream Processing | Event Driven | Real Time > > > > > > -- > > > > > > Ververica GmbH | Invalidenstrasse 115, 10115 Berlin, Germany > > > > > > -- > > > Ververica GmbH > > > Registered at Amtsgericht Charlottenburg: HRB 158244 B > > > Managing Directors: Timothy Alexander Steinert, Yip Park Tung Jason, Ji > > > (Toni) Cheng > > > >
