tests/run-unit-tests: add option to skip tests

In automated QA environments there may be tests that are known to fail,
and being able to skip them is useful to remove known failures from the
test log.

Signed-off-by: Ross Burton <ross.burton@arm.com>

test/run-unit-tests.py

@@ -28,6 +28,9 @@ def argument_parser():
                    help='run "unsafe" tests too')
     p.add_argument('-A', '--artifact_directory',
                    help='store output from failed tests in this dir')
+    p.add_argument('-s', '--skip', action='append', default=[],
+                   help='skip the named test')
+
     return p
 
 opts = argument_parser().parse_args()
@@ -45,6 +48,11 @@ total.total = len(tests)
 for test in sorted(tests):
     name = os.path.basename(test)
 
+    if name in opts.skip:
+        print(f'{YELLOW}SKIP: {name} (by user) {RESET_ALL}')
+        total.skip += 1
+        continue
+
     ex = subprocess.run(test, stdin=subprocess.DEVNULL, stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
     if ex.returncode == 0:
         print(f'{GREEN}PASS: {name}{RESET_ALL}')