Don't enable the add_api_name_to_metadata fixture unless --json-report is used

Author: asmeurer

conftest.py

@@ -2,7 +2,7 @@
 from pathlib import Path
 
 from hypothesis import settings
-from pytest import mark
+from pytest import mark, fixture
 
 from array_api_tests import _array_module as xp
 from array_api_tests._array_module import _UndefinedStub
@@ -126,3 +126,6 @@ def pytest_collection_modifyitems(config, items):
             ci_mark = next((m for m in markers if m.name == "ci"), None)
             if ci_mark is None:
                 item.add_marker(mark.skip(reason="disabled via --ci"))
+
+    if config.getoption('--json-report'):
+        fixture(autouse=True)(add_api_name_to_metadata)

reporting.py

@@ -38,7 +38,8 @@ def pytest_metadata(metadata):
     metadata['array_api_tests_module'] = xp.mod_name
     metadata['array_api_tests_version'] = __version__
 
-@fixture(autouse=True)
+# This is dynamically decorated as a fixture in pytest_collection_modifyitems
+# when --json-report is used.
 def add_api_name_to_metadata(request, json_metadata):
     """
     Additional per-test metadata for --json-report