PluginDoesntContainMetadataException because the wrong findbugs.xml is found when looking for the core plugin about test-driven-detectors4findbugs

[VsevolodGolovanov]

The problem is probably that the target/classes path is the first on classpath.

This is easily fixed in Eclipse by manipulating the Debug configuration, then the tests run successfully.

But the question remains as to how to fix the order in Maven. I'm using maven-surefire-plugin:

The Surefire plugin builds the test classpath in the following order:

1. The test-classes directory
2. The classes directory
3. The project dependencies
4. Additional classpath elements

https://maven.apache.org/surefire/maven-surefire-plugin/examples/configuring-classpath.html

[VsevolodGolovanov]

Moved the classes directory to the end of surefire classpath like this:

<plugin>
    <artifactId>maven-surefire-plugin</artifactId>
    <configuration>
        <!-- disable adding classes to classpath by adding test-classes again -->
        <classesDirectory>${project.build.testOutputDirectory}</classesDirectory>
        <!-- now add classes to the end of classpath -->
        <additionalClasspathElements>
            <additionalClasspathElement>${project.build.outputDirectory}</additionalClasspathElement>
        </additionalClasspathElements>
    </configuration>
</plugin>

But now all tests result in the error:

java.lang.NullPointerException: null
    at edu.umd.cs.findbugs.DetectorToDetector2Adapter.visitClass(DetectorToDetector2Adapter.java:72)
    at com.youdevise.fbplugins.tdd4fb.DetectorRunner$Singleton.doRunDetectorOnClass(DetectorRunner.java:247)
    at com.youdevise.fbplugins.tdd4fb.DetectorRunner$Singleton.access$000(DetectorRunner.java:70)
    at com.youdevise.fbplugins.tdd4fb.DetectorRunner.runDetectorOnClass(DetectorRunner.java:286)
    at com.youdevise.fbplugins.tdd4fb.DetectorAssert.assertNoBugsReported(DetectorAssert.java:107)
    at com.youdevise.fbplugins.tdd4fb.DetectorAssert.assertNoBugsReported(DetectorAssert.java:98)
    at my.company.MyTest$Subtest._(MyTest.java:79)

Looking at the DetectorToDetector2Adapter.visitClass the issue is the null value of the analysisCache thread local. That's because I have this surefire configuration in the parent pom:

<parallel>classes</parallel>
<threadCount>4</threadCount>
<perCoreThreadCount>true</perCoreThreadCount>

I disabled it at the detector project level by overriding:

<parallel>none</parallel>

Now tests pass successfully when launching via Maven.

When launching tests from Eclipse still need to tweak the classpath manually though. m2e won't take the surefire trickery into account.

[VsevolodGolovanov]

I suggest using this task to document how to use tdd4fb with Maven: make classes last on classpath; disable parallel test execution.