Improve testability of SystemCommandTasklet

[scordio]

Currently, the SystemCommandTasklet is not so test-friendly, mainly due to the usage of Runtime.getRuntime().exec(...):

spring-batch/spring-batch-core/src/main/java/org/springframework/batch/core/step/tasklet/SystemCommandTasklet.java

Line 103 in 6b4c916

Process process = Runtime.getRuntime().exec(command, environmentParams, workingDirectory);

For example, testing a job or a step with this tasklet defined does not work properly if the platform running the test does not have the target command available.

Would it make sense to decouple the Runtime dependency from this tasklet, so that a test can have more control over it? I would propose a pattern similar to the SystemExiter and JvmSystemExiter.

I am happy to submit a proposal in case the idea is accepted.

[fmbenhassine]

Thank you for opening this feature request. This makes sense to me, something like CommandRunner and JvmCommandRunner could indeed decouple the command execution from the tasklet and make it possible to mock/stub the CommandRunner in tests. You are welcome to open a PR for that.

[scordio]

Thanks, @benas! I'll work on it.