put slow tests first

jwst/conftest.py

@@ -9,6 +9,39 @@
 from jwst.associations.tests.helpers import t_path
 
 
+# slow test modules (and an example runtime for their slowest test)
+# the runtime is likely dominated by a fixutre reused for tests in that module
+_SLOW_TEST_MODULES = [
+    'jwst.regtest.test_nirspec_ifu_spec3_pixelreplace',  # 4213 seconds
+    'jwst.regtest.test_nirspec_ifu_spec3',  # 3698 seconds
+    'jwst.regtest.test_nirspec_ifu_spec3_emsm',  # 3129 seconds
+    'jwst.regtest.test_niriss_soss',  # 2739 seconds
+    'jwst.regtest.test_nirspec_ifu_spec2',  # 1382 seconds
+    'jwst.regtest.test_nrispec_lamp_ifu_spec2',  # 847 seconds
+    'jwst.regtest.test_nirspec_steps_spec2',  # 710 seconds
+]
+
+
+def _get_test_item_module_name(item):
+    if not hasattr(item, 'module'):
+        return None
+    return item.module.__name__
+
+
+@pytest.hookimpl(trylast=True)
+def pytest_collection_modifyitems(config, items):
+    # reorder tests to put known slow ones first, this helps
+    # to prevent slow tests from starting later in the test run
+    for (i, module_name) in enumerate(_SLOW_TEST_MODULES):
+        if _get_test_item_module_name(items[i]) != module_name:
+            # swap this with a later test not in a slow module
+            for j in range(i, len(items)):
+                if _get_test_item_module_name(items[j]) == module_name:
+                    items[i], items[j] = items[j], items[i]
+                    break
+    return items
+
+
 @pytest.fixture
 def jail_environ():
     """Lock changes to the environment"""