Reject invalid enum values of configuration parameters

[vlsi]

Currently, junit silently accepts invalid values for junit.platform.discovery.issue.severity.critical like warn, so the users might fail to configure JUnit properly.

Here's an example the code which looks wrong: ccfdbd1#diff-3eb48f8e637e1a15e94eb16d5297cfbb97e32c105cb76cfe0a714e652aded9fbR205

At least, when I try warn, it does not work for me with JUnit 5.13.0:

junit.platform.discovery.issue.severity.critical=warn:

Gradle Test Executor 9 STANDARD_ERROR
    июн. 04, 2025 6:52:24 PM org.junit.platform.launcher.core.DiscoveryIssueCollector lambda$getCriticalSeverity$7
    WARNING: Invalid DiscoveryIssue.Severity 'warn' set via the 'junit.platform.discovery.issue.severity.critical' configuration parameter. Falling back to the ERROR default value.
          2,3sec, org.postgresql.core.AsciiStringInternerTest > garbageCleaning()
          2,3sec,    5 completed,   0 failed,   0 skipped, org.postgresql.core.AsciiStringInternerTest

If I specify it as "junit.platform.discovery.issue.severity.critical", "warning", then I manage the discovery to fail.

FAILURE   0,0sec, UnknownClass > initializationError
    org.junit.platform.launcher.core.DiscoveryIssueException: TestEngine with ID 'junit-jupiter' encountered 2 critical issues during test discovery:

    (1) [WARNING] @Test method 'private int org.postgresql.test.jdbc42.SetObject310InfinityTest.abc()' must not be private. It will not be executed.
        Source: MethodSource [className = 'org.postgresql.test.jdbc42.SetObject310InfinityTest', methodName = 'abc', methodParameterTypes = '']
                at org.postgresql.test.jdbc42.SetObject310InfinityTest.abc(SourceFile:0)

    (2) [WARNING] @Test method 'private int org.postgresql.test.jdbc42.SetObject310InfinityTest.abc()' must not return a value. It will not be executed.
        Source: MethodSource [className = 'org.postgresql.test.jdbc42.SetObject310InfinityTest', methodName = 'abc', methodParameterTypes = '']
                at org.postgresql.test.jdbc42.SetObject310InfinityTest.abc(SourceFile:0)

I would prefer JUnit to fail in case user configures an invalid value for junit.platform.discovery.issue.severity.critical.

[marcphilipp]

At least, when I try warn, it does not work for me with JUnit 5.13.0:

You're right: warn doesn't work, it must be warning.

I would prefer JUnit to fail in case user configures an invalid value for junit.platform.discovery.issue.severity.critical.

This was implemented to be consistent with how other enum-based configuration parameters are evaluated (in the Jupiter engine):

https://github.com/junit-team/junit5/blob/1fc5958a092d1be11872f04e850ed9760dcf6953/junit-jupiter-engine/src/main/java/org/junit/jupiter/engine/config/EnumConfigurationParameterConverter.java#L63-L66

That being said, we should discuss if we generally want to change that behavior for 6.0.

[vlsi]

Yeah, making JUnit fail on illegal property values might probably make sense.

[marcphilipp]

Team decision: Fail for all enum-based configuration parameters with invalid values across Platform, Jupiter, and Vintage.