Allow reusing surefire environmentVariables for pitest

[MosheElisha]

Hi,

My code requires quite a lot of environment variables to run properly.
They are configured in the maven-surefire-plugin > configuration > environmentVariables so the unit tests will pass.

The code (and tests) will fail without these environmentVariables (it actually took me a long time to understand that this is the reason why I don't see mutation coverage).

Currently, I need to repeat the environmentVariables I defined in maven-surefire-plugin configuration also in pitest-maven configuration.

Would be great if there can be a way to use the surefire environmentVariables for pitest-maven so they will be defined only once.
Something like mergeSurefireEnvironmentVariables=true.

Current workaround is to place the env var value in a property so at least the value can be shared.

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-surefire-plugin</artifactId>
    <version>${maven.surefire.plugin.version}</version>
    <configuration>
        <environmentVariables>
            <ONE_OF_MANY>value</ONE_OF_MANY>
            ...
        </environmentVariables>
    </configuration>
</plugin>
<plugin>
    <artifactId>pitest-maven</artifactId>
    <groupId>org.pitest</groupId>
    <version>${pitest-maven.version}</version>
    <configuration>
        ...
        <environmentVariables>
            <ONE_OF_MANY>value</ONE_OF_MANY>
            ...
        </environmentVariables>
    </configuration>
</plugin>

[hcoles]

Hi @MosheElisha,

Thanks for the suggestion. This ought to be straight forward, I'll look to include it in the next release.

[hcoles]

This in now implemented in #1319. The behavior is always on, which I shouldn't imagine would cause an issue. If different values are needed when running via pitest, the ones from surefire can be overwritten in the pitest config.

[MosheElisha]

Wow! Perfect! Thanks a lot, @hcoles !