JUnit tests pass in Eclipse but fail in Maven Surefire

Question

I had the same problem (JUnit tests failed in Maven Surefire but passed in Eclipse) and managed to solve it by setting forkMode to always in the maven surefire configuration in pom.xml:

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-surefire-plugin</artifactId>
    <version>2.12</version>
    <configuration>
        <forkMode>always</forkMode>
    </configuration>
</plugin>

Surefire parameters: http://maven.apache.org/plugins/maven-surefire-plugin/test-mojo.html

Edit (January 2014):

As Peter Perháč pointed out, the forkMode parameter is deprecated since Surefire 2.14. Beginning from Surefire 2.14 use this instead:

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-surefire-plugin</artifactId>
    <version>2.16</version>
    <configuration>
        <reuseForks>false</reuseForks>
        <forkCount>1</forkCount>
    </configuration>
</plugin>

For more information see Fork Options and Parallel Test Execution

I suddenly experienced this error, and the solution for me was to disable to run tests in parallel.

Your milage may vary, since I could lower number of failing tests by configuring surefire to run parallel tests by ´classes´.:

            <plugin>
                <artifactId>maven-surefire-plugin</artifactId>
                <version>2.22.2</version>
                <configuration>
                    <parallel>classes</parallel>
                    <threadCount>10</threadCount>
                </configuration>
            </plugin>

As I wrote first, this was not enough for my test suite, so I completely disabled parallel by removing the <configuration> section.

Test execution result different from JUnit run and from maven install seems to be symptom for several problems.

Disabling thread reusing test execution did also get rid of the symptom in our case, but the impression that the code was not thread-safe was still strong.

In our case the difference was due to the presence of a bean that modified the test behaviour. Running just the JUnit test would result fine, but running the project install target would result in a failed test case. Since it was the test case under development, it was immediately suspicious.

It resulted that another test case was instantiating a bean through Spring that would survive until the execution of the new test case. The bean presence was modifying the behaviour of some classes and producing the failed result.

The solution in our case was getting rid of the bean, which was not needed in the first place (yet another prize from the copy+paste gun).

I suggest everybody with this symptom to investigate what the root cause is. Disabling thread reuse in test execution might only hide it.

I had a similar problem, the annotation @Autowired in the test code did not work under using the Maven command line while it worked fine in Eclipse. I just update my JUnit version from 4.4 to 4.9 and the problem was solved.

<dependency>
    <groupId>junit</groupId>
    <artifactId>junit</artifactId>
    <version>4.13.1</version>
</dependency>