Are you ready to test like a pro, or just tired of flaky tests? At Victor Rentea's recent meetup, we delved into the world of JUnit, where testing isnāt just a choreāitās an art. From intercepting test execution to ditching assertEquals
for something better, hereās the breakdown with a dash of humor and visuals to keep you awake.
1. Avoid the Waste: Feature Files Nobody Reads šļø
(I don't believe in this)
If thereās one thing Victor warned us about, itās WASTE. Imagine toiling over .feature
files that no businessperson ever approves. That's like building a ship for people who never plan to sail! Donāt maintain something that doesnāt have value; your tests should be assets, not liabilities. āļø
Pro Tip: Before you dive into feature files, ask yourself: "Will the business actually care?" If not, simplify or refocus those test cases.
Personal Thoughts š: I believe feature files should be written by developers, not even QAs or business people. Even if a businessperson isn't interested, these files are still valuable for maintaining quality and ensuring the code is readable by humans.
2. Say Goodbye to assertEquals
š
assertEquals? We donāt know her. In Victorās world, assertEquals
is yesterdayās news. Why? Because AssertJ and Hamcrest give us way more readable, fluent assertions. Hereās a taste:
// Using AssertJ for clarity
assertThat(myList).contains("Apple").doesNotContain("Orange");
See the difference? AssertJ makes it more obvious whatās expected, giving you readable and maintainable tests. š
3. Parameterized Tests: Go Orthogonal or Go Home š
When it comes to parameterized tests, low multicollinearity is key. What does that mean? Think of it like the spice mix in your favorite dishātoo many overlapping flavors, and you end up with a mess. So, keep your test parameters orthogonal (fancy word for "non-overlapping") to avoid redundancy and ensure youāre truly testing unique combinations. š²
Best Practice: Avoid overlapping parameters that can muddy up your results and make test failures harder to diagnose.
4. From Flaky to Rock-Solid: @RepeatedTest š ļø
Weāve all been thereātests that pass locally but fail in CI, or as we lovingly call them, "flaky tests." Enter @RepeatedTest, the annotation for the ultimate stress test. This lets you repeat a test several times to catch those pesky edge cases that only show up on the third or fourth run.
@RepeatedTest(10)
void shouldPassAllTheTime() {
// Flaky code fixed with multiple runs
}
This isnāt just a ātry until you passā game; itās about consistency and rooting out hidden bugs. š
5. Profiling Tests and OutputCapture š
Imagine running your tests with no clue whatās going on behind the scenes. OutputCapture to the rescue! Use this to capture and analyze your output, giving you insights into what your tests are actually doing. Profiling tests is like a health check-up for your codeāyou get to see whatās slowing you down and optimize as needed. š©ŗ
Essential Tools Youāll Need š§°
Victor recommended a range of tools to supercharge your JUnit testing:
WireMock š¹ļø: A tool for mocking out external services and dependencies. With WireMock, you can simulate HTTP responses, allowing you to test your applicationās behavior without needing access to the real service. This is especially useful in microservices architecture, where services may depend on external APIs that are difficult to control in test environments.
@SpringBootTest & @ActiveProfiles šļø: These annotations in Spring Boot make it easier to control test environments. @SpringBootTest sets up a Spring application context for integration testing, while @ActiveProfiles allows you to specify which profiles should be active during the test. This way, you can isolate configurations and environments for testing, development, and production.
@cucumber & @ContextConfiguration š„: For behavior-driven development (BDD) with Cucumber, @cucumber helps integrate your tests with a Cucumber framework. @ContextConfiguration is used to specify application contexts in Spring Boot, allowing for smooth integration with Cucumber for writing and executing feature files that reflect real-world scenarios.
These tools streamline your testing process, making it possible to test complex scenarios with a consistent setup, saving you from manual setup and tear-down for every test run.
Books & Resources for Further Mastery š
If youāre hungry for more, hereās Victorās recommended reading and watching list:
-
Books:
- Art of Unit Testing by Roy Osherove
- TDD by Example by Kent Beck
- Growing Object-Oriented Software, Guided by Tests by Steve Freeman and Nat Pryce
-
YouTube Talks:
- Devoxx UK: Testing Like a Pro by Victor Rentea
- Testing Microservices by Victor Rentea
Wrapping Up š
JUnit isnāt just a testing framework; itās a philosophy. Use custom annotations wisely, master parameterized tests, and remember, if no oneās reading those .feature
files, maybe itās time to hit delete. As Victor would say, testing is an artāone that requires mastery, dedication, and a good sense of humor. š
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