Summary of Maven Testing Tips
| Command | What it does |
|---|---|
mvn test | Run only backend tests |
mvn test jacoco:report | Run only backend tests, and generate jacoco report |
In web browser: target/site/jacoco/index.html | The detailed backend coverage report |
mvn test pitest:mutationCoverage | Run only backend tests, and generate mutation coverage |
mvn test -DFooTests | Run just a single test file from the backend (specify filename) |
mvn test -DFooTests\#test_method_name | Run just a single test from the backend (specify filename, then \#, then method name of test) |
Details
Suppose you’ve run mvn test and you get a report like this:
Finding and fixing the root cause can be tedious, given that there is so much output.
Here’s a strategy to make it easier:
- First locate the file and test method for a single failure
- Rerun the test suite to focus on only that single failure. Now the output is greatly reduced, and it will be easier to discover the cause!
- Repeat for each test that is failing
For example, in the output above, we see:
SystemInfoControllerTests.systemInfo__logged_out:31 Response status expected:<403> but was:<200>
The information given here tells us which class the test was in (SystemInfoControllerTests) and the name of the method: systemInfo__logged_out. We can turn that into a command that will run only that one test.
(Regrettably, we must replace the . between the class name and method name with \#; that’s just how the system works.)
mvn test -Dtest=SystemInfoControllerTests\#systemInfo__logged_out
Now we can much more easily find the root cause.
Two other tips: I suggest bringing up two windows or tabs in your editor: one with the test that is failing, and another with the “unit under test”, i.e. the specific method that the test is designed to examine.