added test for unique names when recievieng identical ids in parametrize

testing/python/metafunc.py

@@ -265,6 +265,13 @@ class TestMetafunc:
                          ids=["a", None])
         assert result == ["a", "3-4"]
 
+    def test_idmaker_with_ids_unique_names(self):
+        from _pytest.python import idmaker
+        result = idmaker(("a", "b"), [(1, 2),
+                                      (3, 4)],
+                         ids=["a", "a"])
+        assert result == ["0a", "1a"]
+
     def test_addcall_and_parametrize(self):
         def func(x, y): pass
         metafunc = self.Metafunc(func)
@@ -800,7 +807,7 @@ class TestMetafuncFunctional:
         testdir.makepyfile("""
             import pytest
             def pytest_generate_tests(metafunc):
-                metafunc.parametrize(("a", "b"), [(1,1), (1,1) , (1,2)],
+                metafunc.parametrize(("a", "b"), [(1,1), (1,1), (1,2)],
                                      ids=["basic", None, "advanced"])
 
             def test_function(a, b):
@@ -814,6 +821,23 @@ class TestMetafuncFunctional:
             "*test_function*advanced*FAILED",
         ])
 
+    def test_parametrize_with_identical_ids_get_unique_names(self, testdir):
+        testdir.makepyfile("""
+            import pytest
+            def pytest_generate_tests(metafunc):
+                metafunc.parametrize(("a", "b"), [(1,1), (1,2)],
+                                     ids=["a", "a"])
+
+            def test_function(a, b):
+                assert a == b
+        """)
+        result = testdir.runpytest("-v")
+        assert result.ret == 1
+        result.stdout.fnmatch_lines_random([
+            "*test_function*0a*PASSED",
+            "*test_function*1a*FAILED"
+        ])
+
     @pytest.mark.parametrize(("scope", "length"),
                              [("module", 2), ("function", 4)])
     def test_parametrize_scope_overrides(self, testdir, scope, length):