[feat] Emit JUnit report in child pipeline CI jobs

docs/tutorial_tips_tricks.rst

@@ -556,6 +556,7 @@ ReFrame will process them as usual, but instead of running the selected tests, i
 for running each test individually as a Gitlab job. We then pass the generated CI pipeline file to second phase as
 an artifact and we are done! If ``image`` keyword is defined in ``.gitlab-ci.yml``, the emitted pipeline will use
 the same image as the one defined in the parent pipeline.
+Besides, each job in the generated pipeline will output a separate junit report which can be used to create GitLab badges.
 
 The following figure shows one part of the automatically generated pipeline for the test graph depicted `above <#fig-deps-complex>`__.
 

reframe/frontend/ci.py

@@ -42,6 +42,7 @@ def rfm_command(testcase):
             f'-R' if recurse else '',
             f'--report-file={report_file}',
             f'--restore-session={restore_files}' if restore_files else '',
+            f'--report-junit={testcase.check.name}-report.xml',
             f'{"".join("-" + verbosity)}' if verbosity else '',
             '-n', f"'^{testcase.check.name}$'", '-r'
         ])