Running "python -m unittest" failing with maven exec-maven-plugin

I'm trying to set up my maven build so that mvn test runs my python tests in addition to my Java tests. I'm trying to use the exec-maven-plugin to do this.

My pom.xml has:

<plugin>
  <groupId>org.codehaus.mojo</groupId>
  <artifactId>exec-maven-plugin</artifactId>
  <version>3.0.0</version>
  <executions>
    <execution>
      <configuration>
        <executable>python3</executable>
        <workingDirectory>${project.basedir}/src/main/resources/scripts/</workingDirectory>
        <arguments>
          <argument>-m</argument>
          <argument>unittest</argument>
          <argument>discover</argument>
          <argument>-p</argument>
          <argument>'*_test.py'</argument>
        </arguments>
      </configuration>
      <id>python-test</id>
      <phase>test</phase>
      <goals>
        <goal>exec</goal>
      </goals>
    </execution>
  </executions>
</plugin>

My project structure is like:

.
├── pom.xml
├── src
│   ├── main
│   │   └── resources
│   │       ├── scripts
│   │       │   ├── __init__.py
│   │       │   ├── foo.py
│   │       │   ├── foo_test.py

When I try to run it from the project root:

mvn exec:exec@python-test

I get 0 tests ran:

----------------------------------------------------------------------
Ran 0 tests in 0.000s

OK

But, if I do this manually, it works fine:

cd src/main/resources/scripts 
python3 -m unittest discover -p '*_test.py' 
...
----------------------------------------------------------------------
Ran 3 tests in 0.010s

What am I doing wrong here?

Thanks in advance!

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