dont use exception catches for warnings; modernize xdist detection

Improvements to the test suite's integration with pytest such that the
"warnings" plugin, if manually enabled, will not interfere with the test
suite, such that third parties can enable the warnings plugin or make use
of the ``-W`` parameter and SQLAlchemy's test suite will continue to pass.
Additionally, modernized the detection of the "pytest-xdist" plugin so that
plugins can be globally disabled using PYTEST_DISABLE_PLUGIN_AUTOLOAD=1
without breaking the test suite if xdist were still installed. Warning
filters that promote deprecation warnings to errors are now localized to
SQLAlchemy-specific warnings, or within SQLAlchemy-specific sources for
general Python deprecation warnings, so that non-SQLAlchemy deprecation
warnings emitted from pytest plugins should also not impact the test suite.

Fixes: #7599
Change-Id: Ibcf09af25228d39ee5a943fda82d8a9302433726

1 files changed, 10 insertions, 9 deletions

diff --git a/test/orm/test_relationships.py b/test/orm/test_relationships.py
index f91e7e8d5..fd192ab51 100644
--- a/test/orm/test_relationships.py
+++ b/test/orm/test_relationships.py
@@ -33,13 +33,14 @@ from sqlalchemy.orm.interfaces import MANYTOONE
 from sqlalchemy.orm.interfaces import ONETOMANY
 from sqlalchemy.testing import assert_raises
 from sqlalchemy.testing import assert_raises_message
+from sqlalchemy.testing import assert_warns_message
 from sqlalchemy.testing import AssertsCompiledSQL
 from sqlalchemy.testing import eq_
+from sqlalchemy.testing import expect_raises_message
+from sqlalchemy.testing import expect_warnings
 from sqlalchemy.testing import fixtures
 from sqlalchemy.testing import in_
 from sqlalchemy.testing import is_
-from sqlalchemy.testing.assertions import expect_raises_message
-from sqlalchemy.testing.assertions import expect_warnings
 from sqlalchemy.testing.assertsql import assert_engine
 from sqlalchemy.testing.assertsql import CompiledSQL
 from sqlalchemy.testing.fixtures import fixture_session
@@ -873,7 +874,7 @@ class OverlappingFksSiblingTest(fixtures.MappedTest):
 
     @testing.provide_metadata
     def test_simple_warn(self):
-        assert_raises_message(
+        assert_warns_message(
             exc.SAWarning,
             r"relationship '(?:Child.parent|Parent.children)' will copy "
             r"column parent.id to column child.parent_id, which conflicts "
@@ -964,7 +965,7 @@ class OverlappingFksSiblingTest(fixtures.MappedTest):
 
     @testing.provide_metadata
     def test_double_rel_same_mapper_warns(self):
-        assert_raises_message(
+        assert_warns_message(
             exc.SAWarning,
             r"relationship 'Parent.child[12]' will copy column parent.id to "
             r"column child.parent_id, which conflicts with relationship\(s\): "
@@ -984,7 +985,7 @@ class OverlappingFksSiblingTest(fixtures.MappedTest):
 
     @testing.provide_metadata
     def test_warn_one(self):
-        assert_raises_message(
+        assert_warns_message(
             exc.SAWarning,
             r"relationship '(?:BSub1.a|BSub2.a_member|B.a)' will copy column "
             r"(?:a.id|a_member.a_id) to column b.a_id",
@@ -995,7 +996,7 @@ class OverlappingFksSiblingTest(fixtures.MappedTest):
 
     @testing.provide_metadata
     def test_warn_two(self):
-        assert_raises_message(
+        assert_warns_message(
             exc.SAWarning,
             r"relationship '(?:BSub1.a|B.a_member)' will copy column "
             r"(?:a.id|a_member.a_id) to column b.a_id",
@@ -1006,7 +1007,7 @@ class OverlappingFksSiblingTest(fixtures.MappedTest):
 
     @testing.provide_metadata
     def test_warn_three(self):
-        assert_raises_message(
+        assert_warns_message(
             exc.SAWarning,
             r"relationship '(?:BSub1.a|B.a_member|B.a)' will copy column "
             r"(?:a.id|a_member.a_id) to column b.a_id",
@@ -1018,7 +1019,7 @@ class OverlappingFksSiblingTest(fixtures.MappedTest):
 
     @testing.provide_metadata
     def test_warn_four(self):
-        assert_raises_message(
+        assert_warns_message(
             exc.SAWarning,
             r"relationship '(?:B.a|BSub2.a_member|B.a)' will copy column "
             r"(?:a.id|a_member.a_id) to column b.a_id",
@@ -1302,7 +1303,7 @@ class CompositeSelfRefFKTest(fixtures.MappedTest, AssertsCompiledSQL):
             },
         )
 
-        assert_raises_message(
+        assert_warns_message(
             exc.SAWarning,
             r"relationship .* will copy column .* to column "
             r"employee_t.company_id, which conflicts with relationship\(s\)",