TST: Refactor index setops test for xdist stability (#48010)

Author: mroeschke

pandas/conftest.py

@@ -665,21 +665,6 @@ def index_flat(request):
 index_flat2 = index_flat
 
 
-@pytest.fixture(
-    params=[
-        key
-        for key in indices_dict
-        if not isinstance(indices_dict[key], MultiIndex) and indices_dict[key].is_unique
-    ]
-)
-def index_flat_unique(request):
-    """
-    index_flat with uniqueness requirement.
-    """
-    key = request.param
-    return indices_dict[key].copy()
-
-
 @pytest.fixture(
     params=[
         key

pandas/tests/indexes/test_setops.py

@@ -317,11 +317,13 @@ def test_symmetric_difference(self, index):
             (None, None, None),
         ],
     )
-    def test_corner_union(self, index_flat_unique, fname, sname, expected_name):
+    def test_corner_union(self, index_flat, fname, sname, expected_name):
         # GH#9943, GH#9862
         # Test unions with various name combinations
         # Do not test MultiIndex or repeats
-        index = index_flat_unique
+        if not index_flat.is_unique:
+            pytest.skip("Randomly generated index_flat was not unique.")
+        index = index_flat
 
         # Test copy.union(copy)
         first = index.copy().set_names(fname)
@@ -361,8 +363,10 @@ def test_corner_union(self, index_flat_unique, fname, sname, expected_name):
             (None, None, None),
         ],
     )
-    def test_union_unequal(self, index_flat_unique, fname, sname, expected_name):
-        index = index_flat_unique
+    def test_union_unequal(self, index_flat, fname, sname, expected_name):
+        if not index_flat.is_unique:
+            pytest.skip("Randomly generated index_flat was not unique.")
+        index = index_flat
 
         # test copy.union(subset) - need sort for unicode and string
         first = index.copy().set_names(fname)
@@ -381,10 +385,12 @@ def test_union_unequal(self, index_flat_unique, fname, sname, expected_name):
             (None, None, None),
         ],
     )
-    def test_corner_intersect(self, index_flat_unique, fname, sname, expected_name):
+    def test_corner_intersect(self, index_flat, fname, sname, expected_name):
         # GH#35847
         # Test intersections with various name combinations
-        index = index_flat_unique
+        if not index_flat.is_unique:
+            pytest.skip("Randomly generated index_flat was not unique.")
+        index = index_flat
 
         # Test copy.intersection(copy)
         first = index.copy().set_names(fname)
@@ -424,8 +430,10 @@ def test_corner_intersect(self, index_flat_unique, fname, sname, expected_name):
             (None, None, None),
         ],
     )
-    def test_intersect_unequal(self, index_flat_unique, fname, sname, expected_name):
-        index = index_flat_unique
+    def test_intersect_unequal(self, index_flat, fname, sname, expected_name):
+        if not index_flat.is_unique:
+            pytest.skip("Randomly generated index_flat was not unique.")
+        index = index_flat
 
         # test copy.intersection(subset) - need sort for unicode and string
         first = index.copy().set_names(fname)