Add option for "sparse" backend tests and apply to memusage

The memusage tests are extremely time and memory intensive,
and when CI runs against MySQL or Postgresql there are many
database/driver combinations for which the "backend" tests
repeatedly run; as these tests are more oriented towards
basic dialect interaction, add a new "sparse" backend option
that will run the tests only once per base dialect.

Change-Id: I312aa0332d7ec1ff4e2faa15f6b189d6f0f68393

diff --git a/lib/sqlalchemy/testing/plugin/plugin_base.py b/lib/sqlalchemy/testing/plugin/plugin_base.py
index ef44a5906bc7ace2982cf2531c622bab913126cd..8f79b416314745639ffa1eda90e30ac2b704b19e 100644 (file)
--- a/lib/sqlalchemy/testing/plugin/plugin_base.py
+++ b/lib/sqlalchemy/testing/plugin/plugin_base.py
@@ -93,7 +93,7 @@ def setup_options(make_option):
         "--backend-only",
         action="store_true",
         dest="backend_only",
-        help="Run only tests marked with __backend__",
+        help="Run only tests marked with __backend__ or __sparse_backend__",
     )
     make_option(
         "--nomemory",
@@ -483,8 +483,10 @@ def want_class(cls):
         return False
     elif cls.__name__.startswith("_"):
         return False
-    elif config.options.backend_only and not getattr(
-        cls, "__backend__", False
+    elif (
+        config.options.backend_only
+        and not getattr(cls, "__backend__", False)
+        and not getattr(cls, "__sparse_backend__", False)
     ):
         return False
     else:
@@ -519,8 +521,11 @@ def want_method(cls, fn):
 
 
 def generate_sub_tests(cls, module):
-    if getattr(cls, "__backend__", False):
-        for cfg in _possible_configs_for_cls(cls):
+    if getattr(cls, "__backend__", False) or getattr(
+        cls, "__sparse_backend__", False
+    ):
+        sparse = getattr(cls, "__sparse_backend__", False)
+        for cfg in _possible_configs_for_cls(cls, sparse=sparse):
             orig_name = cls.__name__
 
             # we can have special chars in these names except for the
@@ -589,7 +594,7 @@ def after_test(test):
     engines.testing_reaper._after_test_ctx()
 
 
-def _possible_configs_for_cls(cls, reasons=None):
+def _possible_configs_for_cls(cls, reasons=None, sparse=False):
     all_configs = set(config.Config.all_configs())
 
     if cls.__unsupported_on__:
@@ -632,6 +637,25 @@ def _possible_configs_for_cls(cls, reasons=None):
         if all_configs.difference(non_preferred):
             all_configs.difference_update(non_preferred)
 
+    if sparse:
+        # pick only one config from each base dialect
+        # sorted so we get the same backend each time selecting the highest
+        # server version info.
+        per_dialect = {}
+        for cfg in reversed(
+            sorted(
+                all_configs,
+                key=lambda cfg: (
+                    cfg.db.name,
+                    cfg.db.dialect.server_version_info,
+                ),
+            )
+        ):
+            db = cfg.db.name
+            if db not in per_dialect:
+                per_dialect[db] = cfg
+        return per_dialect.values()
+
     return all_configs
 
 

diff --git a/test/aaa_profiling/test_memusage.py b/test/aaa_profiling/test_memusage.py
index bcd48e71c990a3fbb67eaed1512d8082d10531ad..d172c4a87d0fbd2be64a69f01600ebaafbd8823b 100644 (file)
--- a/test/aaa_profiling/test_memusage.py
+++ b/test/aaa_profiling/test_memusage.py
@@ -264,7 +264,7 @@ class MemUsageWBackendTest(EnsureZeroed):
 
     __tags__ = ("memory_intensive",)
     __requires__ = "cpython", "memory_process_intensive"
-    __backend__ = True
+    __sparse_backend__ = True
 
     # ensure a pure growing test trips the assertion
     @testing.fails_if(lambda: True)