catch_discover_tests registers tests with --order decl

Catch2 defaults to random test execution order, which has to process
all tests present in the binary, even if they will be filtered down
to just 1 later. For the `SelfTest` binary, the overhead from this is
about 20% in Debug configuration and 5% in Release.

By registering the CTest tests with `--order decl`, we avoid this
overhead.

1 files changed, 4 insertions, 3 deletions

diff --git a/tests/TestScripts/DiscoverTests/VerifyRegistration.py b/tests/TestScripts/DiscoverTests/VerifyRegistration.py
index d33006dd..e213bd3d 100644
--- a/tests/TestScripts/DiscoverTests/VerifyRegistration.py
+++ b/tests/TestScripts/DiscoverTests/VerifyRegistration.py
@@ -92,7 +92,7 @@ def get_test_names(build_path: str) -> List[TestInfo]:
         with open(fname, mode='r', encoding='utf-8') as file:
             test_listing = json.load(file)
 
-    assert test_listing['version'] == 2
+    assert test_listing['version'] == 2, test_listing['version']
 
     tests = []
     for test in test_listing['listings']['tests']:
@@ -129,10 +129,11 @@ def extract_tests_from_ctest(ctest_output) -> List[TestInfo]:
     test_infos = []
     for test in tests:
         test_command = test['command']
-        # First part of the command is the binary, second is the filter.
+        # First part of the command is the binary, second is the filter,
+        # third is the `--order decl` arg for faster startup.
         # If there are less, registration has failed. If there are more,
         # registration has changed and the script needs updating.
-        assert len(test_command) == 2
+        assert len(test_command) == 3, test_command
         test_name = test_command[1]
         labels = []
         for prop in test['properties']: