Please add an automated test

Hello @reda-alaoui

I have no experience writing a Maven plugin, and therefore no experience writing a proper test for it either.

For the PoC, I based my changes on the code that already exists in the project right now, in particular on the code for the propertiesToAdd config property. However, I don't find a specific test for the propertiesToAdd config property (or one of the other config properties) which I could use as a starting point for a test for the new config property (but maybe I overlooked it).

I only did a manual test by doing a mvn clean install of my feature branch and using that new SNAPSHOT version of the plugin on a test project to verify the generated pre-commit script.

  <properties>
    <git-code-format-maven-plugin.version>6.1-SNAPSHOT</git-code-format-maven-plugin.version>
  </properties>

  <build>
    <plugins>
      <plugin>
        <groupId>com.cosium.code</groupId>
        <artifactId>git-code-format-maven-plugin</artifactId>
        <version>${git-code-format-maven-plugin.version}</version>
        <dependencies>
          <!-- Enable https://github.com/google/google-java-format -->
          <dependency>
            <groupId>com.cosium.code</groupId>
            <artifactId>google-java-format</artifactId>
            <version>${git-code-format-maven-plugin.version}</version>
          </dependency>
        </dependencies>
        <configuration>
          <preliminaryGoals>
            <preliminaryGoal>build-helper:add-test-source@add-integration-test-source</preliminaryGoal>
            <preliminaryGoal>build-helper:add-test-source@add-acceptance-test-source</preliminaryGoal>
          </preliminaryGoals>
          <!-- enable hook execution verbose mode -->
          <!-- <propertiesToAdd>
            <prop>-X</prop>
          </propertiesToAdd> -->
        </configuration>
      </plugin>
    </plugins>
  </build>

With the above config, the contents of the generated pre-commit script is as follows:

#!/bin/bash
set -e
"C:/dev/java/maven/default/bin/mvn.cmd" -f "C:/dev/prj/my-group/my-project/pom.xml" build-helper:add-test-source@add-integration-test-source build-helper:add-test-source@add-acceptance-test-source com.cosium.code:git-code-format-maven-plugin:on-pre-commit 

Kind regards.

@reda-alaoui Is an automated test for this new configuration parameter indispensable for this change to be merged considering that there are no automated tests for the already existing configuration parameters either?

@duke1995 I don't have much time these days to maintain this project. So automated tests for this feature would be of course better since they would partially alleviate the maintaince burden: an automatic test will greatly facilitate the validation of this pull request.