[tests] Check tests conform to naming convention

Extra-Author: John Newbery <john@johnnewbery.com>

test/functional/test_runner.py

@@ -260,6 +260,7 @@ def main():
         sys.exit(0)
 
     check_script_list(config["environment"]["SRCDIR"])
+    check_script_prefixes()
 
     if not args.keepcache:
         shutil.rmtree("%s/test/cache" % config["environment"]["BUILDDIR"], ignore_errors=True)
@@ -444,6 +445,28 @@ class TestResult():
         return self.status != "Failed"
 
 
+def check_script_prefixes():
+    """Check that no more than `EXPECTED_VIOLATION_COUNT` of the
+       test scripts don't start with one of the allowed name prefixes."""
+    EXPECTED_VIOLATION_COUNT = 77
+
+    # LEEWAY is provided as a transition measure, so that pull-requests
+    # that introduce new tests that don't conform with the naming
+    # convention don't immediately cause the tests to fail.
+    LEEWAY = 10
+
+    good_prefixes_re = re.compile("(example|feature|interface|mempool|mining|p2p|rpc|wallet)_")
+    bad_script_names = [script for script in ALL_SCRIPTS if good_prefixes_re.match(script) is None]
+
+    if len(bad_script_names) < EXPECTED_VIOLATION_COUNT:
+        print("{}HURRAY!{} Number of functional tests violating naming convention reduced!".format(BOLD[1], BOLD[0]))
+        print("Consider reducing EXPECTED_VIOLATION_COUNT from %d to %d" % (EXPECTED_VIOLATION_COUNT, len(bad_script_names)))
+    elif len(bad_script_names) > EXPECTED_VIOLATION_COUNT:
+        print("INFO: %d tests not meeting naming conventions (expected %d):" % (len(bad_script_names), EXPECTED_VIOLATION_COUNT))
+        print("  %s" % ("\n  ".join(sorted(bad_script_names))))
+        assert len(bad_script_names) <= EXPECTED_VIOLATION_COUNT + LEEWAY, "Too many tests not following naming convention! (%d found, expected: <= %d)" % (len(bad_script_names), EXPECTED_VIOLATION_COUNT)
+
+
 def check_script_list(src_dir):
     """Check scripts directory.