use np.sctypes to extract all dtypes

Author: ganevgv

pandas/tests/series/test_dtypes.py

@@ -506,33 +506,6 @@ def test_is_homogeneous_type(self):
         assert Series([1, 2])._is_homogeneous_type
         assert Series(pd.Categorical([1, 2]))._is_homogeneous_type
 
-    @pytest.mark.parametrize(
-        "data, uniques, dtype",
-        [
-            ([1, 2, 2], [1, 2], "int8"),
-            ([1, 2, 2], [1, 2], "int16"),
-            ([1, 2, 2], [1, 2], "int32"),
-            ([1, 2, 2], [1, 2], "int64"),
-            ([1, 2, 2], [1, 2], "uint8"),
-            ([1, 2, 2], [1, 2], "uint16"),
-            ([1, 2, 2], [1, 2], "uint32"),
-            ([1, 2, 2], [1, 2], "uint64"),
-            ([1, 2, 2], [1.0, 2.0], "float16"),
-            ([1, 2, 2], [1.0, 2.0], "float32"),
-            ([1, 2, 2], [1.0, 2.0], "float64"),
-            ([1, 2, 2], [1.0, 2.0], "complex64"),
-            ([1, 2, 2], [1.0, 2.0], "complex128"),
-            ([True, True, False], [True, False], "bool"),
-            (["A", "A", "B"], ["A", "B"], "object"),
-        ],
-    )
-    def test_unique_preserve_dtype(self, data, uniques, dtype):
-        # GH 15442
-        result = Series(data, dtype=dtype).unique()
-        expected = np.array(uniques, dtype=dtype)
-
-        tm.assert_numpy_array_equal(result, expected)
-
     @pytest.mark.parametrize(
         "data",
         [

pandas/tests/test_algos.py

@@ -353,6 +353,25 @@ def test_on_index_object(self):
 
         tm.assert_almost_equal(result, expected)
 
+    @pytest.mark.parametrize(
+        "data, uniques, dtype_list",
+        [
+            ([1, 2, 2], [1, 2], np.sctypes["int"]),
+            ([1, 2, 2], [1, 2], np.sctypes["uint"]),
+            ([1, 2, 2], [1.0, 2.0], np.sctypes["float"]),
+            ([1, 2, 2], [1.0, 2.0], np.sctypes["complex"]),
+            ([True, True, False], [True, False], np.sctypes["others"]),  # bool, object
+        ],
+    )
+    def test_dtype_preservation(self, data, uniques, dtype_list):
+        # GH 15442
+        for dtype in dtype_list:
+            if dtype not in [bytes, str, np.void]:
+                result = Series(data, dtype=dtype).unique()
+                expected = np.array(uniques, dtype=dtype)
+
+                tm.assert_numpy_array_equal(result, expected)
+
     def test_datetime64_dtype_array_returned(self):
         # GH 9431
         expected = np_array_datetime64_compat(