[feat] Add a --list-tags command-line action to list all the available test tags

docs/manpage.rst

@@ -166,6 +166,14 @@ An action must always be specified.
    List selected tests providing detailed information per test.
 
 
+.. option:: --list-tags
+
+   List the unique tags of the selected tests.
+   The tags are printed in alphabetical order.
+
+   .. versionadded:: 3.6.0
+
+
 .. option:: -r, --run
 
    Execute the selected tests.

reframe/frontend/cli.py

@@ -123,6 +123,14 @@ def list_checks(testcases, printer, detailed=False):
     printer.info(f'Found {len(checks)} check(s)\n')
 
 
+def list_tags(testcases, printer):
+    printer.info('[List of unique tags]')
+    tags = set()
+    tags = tags.union(*(t.check.tags for t in testcases))
+    printer.info(', '.join(f'{t!r}' for t in sorted(tags)))
+    printer.info(f'Found {len(tags)} tag(s)\n')
+
+
 def logfiles_message():
     log_files = logging.log_files()
     msg = 'Log file(s) saved in: '
@@ -269,6 +277,10 @@ def main():
         '-L', '--list-detailed', action='store_true',
         help='List the selected checks providing details for each test'
     )
+    action_options.add_argument(
+        '--list-tags', action='store_true',
+        help='List the unique tags found in the selected tests and exit'
+    )
     action_options.add_argument(
         '-r', '--run', action='store_true',
         help='Run the selected checks'
@@ -810,6 +822,10 @@ def _case_failed(t):
             list_checks(testcases, printer, options.list_detailed)
             sys.exit(0)
 
+        if options.list_tags:
+            list_tags(testcases, printer)
+            sys.exit(0)
+
         if options.ci_generate:
             list_checks(testcases, printer)
             printer.info('[Generate CI]')
@@ -826,6 +842,7 @@ def _case_failed(t):
             printer.error("No action option specified. Available options:\n"
                           "  - `-l'/`-L' for listing\n"
                           "  - `-r' for running\n"
+                          "  - `--list-tags' for listing unique test tags\n"
                           "  - `--ci-generate' for generating a CI pipeline\n"
                           f"Try `{argparser.prog} -h' for more options.")
             sys.exit(1)

unittests/test_cli.py

@@ -89,6 +89,8 @@ def _run_reframe(system='generic:default',
             argv += ['-l']
         elif action == 'list_detailed':
             argv += ['-L']
+        elif action == 'list_tags':
+            argv += ['--list-tags']
         elif action == 'help':
             argv += ['-h']
 
@@ -540,6 +542,19 @@ def test_list_with_details(run_reframe):
     assert returncode == 0
 
 
+def test_list_tags(run_reframe):
+    returncode, stdout, stderr = run_reframe(
+        checkpath=['unittests/resources/checks/hellocheck.py',
+                   'unittests/resources/checks/hellocheck_make.py'],
+        action='list_tags'
+    )
+    assert 'Traceback' not in stdout
+    assert 'Traceback' not in stderr
+    assert 'Found 2 tag(s)' in stdout
+    assert "'bar', 'foo'" in stdout
+    assert returncode == 0
+
+
 def test_filtering_multiple_criteria(run_reframe):
     returncode, stdout, stderr = run_reframe(
         checkpath=['unittests/resources/checks'],