twister: support scanning for ztests in subdirectories

Previously, only the main src/ directories was scanned for
ZTest testsuite names and tests. This allows us to place
test sources in subdirectories as well.

(cherry picked from commit 20b81a8)

Original-Signed-off-by: Christopher Friedt <cfriedt@meta.com>
GitOrigin-RevId: 20b81a8
Change-Id: I71eeca8fbc6dca6cdf5b992c983509e00c691e40
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/zephyr/+/4853667
Commit-Queue: Keith Short <keithshort@chromium.org>
Tested-by: ChromeOS Prod (Robot) <chromeos-ci-prod@chromeos-bot.iam.gserviceaccount.com>
Reviewed-by: Fabio Baltieri <fabiobaltieri@google.com>
Tested-by: Keith Short <keithshort@chromium.org>

scripts/pylib/twister/twisterlib/testsuite.py

@@ -256,6 +256,28 @@ def _find_ztest_testcases(search_area, testcase_regex):
 
  return testcase_names, warnings
 
+def find_c_files_in(path: str, extensions: list = ['c', 'cpp', 'cxx', 'cc']) -> list:
+ """
+ Find C or C++ sources in the directory specified by "path"
+ """
+ if not os.path.isdir(path):
+ return []
+
+ # back up previous CWD
+ oldpwd = os.getcwd()
+ os.chdir(path)
+
+ filenames = []
+ for ext in extensions:
+ # glob.glob('**/*.c') does not pick up the base directory
+ filenames += [os.path.join(path, x) for x in glob.glob(f'*.{ext}')]
+ # glob matches in subdirectories too
+ filenames += [os.path.join(path, x) for x in glob.glob(f'**/*.{ext}')]
+
+ # restore previous CWD
+ os.chdir(oldpwd)
+
+ return filenames
 
 def scan_testsuite_path(testsuite_path):
  subcases = []
@@ -265,7 +287,7 @@ def scan_testsuite_path(testsuite_path):
  ztest_suite_names = []
 
  src_dir_path = _find_src_dir_path(testsuite_path)
- for filename in glob.glob(os.path.join(src_dir_path, "*.c*")):
+ for filename in find_c_files_in(src_dir_path):
  if os.stat(filename).st_size == 0:
  continue
  try:
@@ -288,7 +310,7 @@ def scan_testsuite_path(testsuite_path):
  except ValueError as e:
  logger.error("%s: error parsing source file: %s" % (filename, e))
 
- for filename in glob.glob(os.path.join(testsuite_path, "*.c*")):
+ for filename in find_c_files_in(testsuite_path):
  try:
  result: ScanPathResult = scan_file(filename)
  if result.warnings: