REF: .dot tests (pandas-dev#33214)

Author: jbrockmendel

pandas/tests/frame/test_analytics.py

@@ -1147,59 +1147,6 @@ def test_any_all_level_axis_none_raises(self, method):
     # ---------------------------------------------------------------------
     # Matrix-like
 
-    def test_dot(self):
-        a = DataFrame(
-            np.random.randn(3, 4), index=["a", "b", "c"], columns=["p", "q", "r", "s"]
-        )
-        b = DataFrame(
-            np.random.randn(4, 2), index=["p", "q", "r", "s"], columns=["one", "two"]
-        )
-
-        result = a.dot(b)
-        expected = DataFrame(
-            np.dot(a.values, b.values), index=["a", "b", "c"], columns=["one", "two"]
-        )
-        # Check alignment
-        b1 = b.reindex(index=reversed(b.index))
-        result = a.dot(b)
-        tm.assert_frame_equal(result, expected)
-
-        # Check series argument
-        result = a.dot(b["one"])
-        tm.assert_series_equal(result, expected["one"], check_names=False)
-        assert result.name is None
-
-        result = a.dot(b1["one"])
-        tm.assert_series_equal(result, expected["one"], check_names=False)
-        assert result.name is None
-
-        # can pass correct-length arrays
-        row = a.iloc[0].values
-
-        result = a.dot(row)
-        expected = a.dot(a.iloc[0])
-        tm.assert_series_equal(result, expected)
-
-        with pytest.raises(ValueError, match="Dot product shape mismatch"):
-            a.dot(row[:-1])
-
-        a = np.random.rand(1, 5)
-        b = np.random.rand(5, 1)
-        A = DataFrame(a)
-
-        # TODO(wesm): unused
-        B = DataFrame(b)  # noqa
-
-        # it works
-        result = A.dot(b)
-
-        # unaligned
-        df = DataFrame(np.random.randn(3, 4), index=[1, 2, 3], columns=range(4))
-        df2 = DataFrame(np.random.randn(5, 3), index=range(5), columns=[1, 2, 3])
-
-        with pytest.raises(ValueError, match="aligned"):
-            df.dot(df2)
-
     def test_matmul(self):
         # matmul test is for GH 10259
         a = DataFrame(

pandas/tests/generic/methods/test_dot.py

@@ -0,0 +1,128 @@
+import numpy as np
+import pytest
+
+from pandas import DataFrame, Series
+import pandas._testing as tm
+
+
+class DotSharedTests:
+    @pytest.fixture
+    def obj(self):
+        raise NotImplementedError
+
+    @pytest.fixture
+    def other(self) -> DataFrame:
+        """
+        other is a DataFrame that is indexed so that obj.dot(other) is valid
+        """
+        raise NotImplementedError
+
+    @pytest.fixture
+    def expected(self, obj, other) -> DataFrame:
+        """
+        The expected result of obj.dot(other)
+        """
+        raise NotImplementedError
+
+    @classmethod
+    def reduced_dim_assert(cls, result, expected):
+        """
+        Assertion about results with 1 fewer dimension that self.obj
+        """
+        raise NotImplementedError
+
+    def test_dot_equiv_values_dot(self, obj, other, expected):
+        # `expected` is constructed from obj.values.dot(other.values)
+        result = obj.dot(other)
+        tm.assert_equal(result, expected)
+
+    def test_dot_2d_ndarray(self, obj, other, expected):
+        # Check ndarray argument; in this case we get matching values,
+        #  but index/columns may not match
+        result = obj.dot(other.values)
+        assert np.all(result == expected.values)
+
+    def test_dot_1d_ndarray(self, obj, expected):
+        # can pass correct-length array
+        row = obj.iloc[0] if obj.ndim == 2 else obj
+
+        result = obj.dot(row.values)
+        expected = obj.dot(row)
+        self.reduced_dim_assert(result, expected)
+
+    def test_dot_series(self, obj, other, expected):
+        # Check series argument
+        result = obj.dot(other["1"])
+        self.reduced_dim_assert(result, expected["1"])
+
+    def test_dot_series_alignment(self, obj, other, expected):
+        result = obj.dot(other.iloc[::-1]["1"])
+        self.reduced_dim_assert(result, expected["1"])
+
+    def test_dot_aligns(self, obj, other, expected):
+        # Check index alignment
+        other2 = other.iloc[::-1]
+        result = obj.dot(other2)
+        tm.assert_equal(result, expected)
+
+    def test_dot_shape_mismatch(self, obj):
+        msg = "Dot product shape mismatch"
+        # exception raised is of type Exception
+        with pytest.raises(Exception, match=msg):
+            obj.dot(obj.values[:3])
+
+    def test_dot_misaligned(self, obj, other):
+        msg = "matrices are not aligned"
+        with pytest.raises(ValueError, match=msg):
+            obj.dot(other.T)
+
+
+class TestSeriesDot(DotSharedTests):
+    @pytest.fixture
+    def obj(self):
+        return Series(np.random.randn(4), index=["p", "q", "r", "s"])
+
+    @pytest.fixture
+    def other(self):
+        return DataFrame(
+            np.random.randn(3, 4), index=["1", "2", "3"], columns=["p", "q", "r", "s"]
+        ).T
+
+    @pytest.fixture
+    def expected(self, obj, other):
+        return Series(np.dot(obj.values, other.values), index=other.columns)
+
+    @classmethod
+    def reduced_dim_assert(cls, result, expected):
+        """
+        Assertion about results with 1 fewer dimension that self.obj
+        """
+        tm.assert_almost_equal(result, expected)
+
+
+class TestDataFrameDot(DotSharedTests):
+    @pytest.fixture
+    def obj(self):
+        return DataFrame(
+            np.random.randn(3, 4), index=["a", "b", "c"], columns=["p", "q", "r", "s"]
+        )
+
+    @pytest.fixture
+    def other(self):
+        return DataFrame(
+            np.random.randn(4, 2), index=["p", "q", "r", "s"], columns=["1", "2"]
+        )
+
+    @pytest.fixture
+    def expected(self, obj, other):
+        return DataFrame(
+            np.dot(obj.values, other.values), index=obj.index, columns=other.columns
+        )
+
+    @classmethod
+    def reduced_dim_assert(cls, result, expected):
+        """
+        Assertion about results with 1 fewer dimension that self.obj
+        """
+        tm.assert_series_equal(result, expected, check_names=False)
+        assert result.name is None

pandas/tests/series/test_analytics.py

@@ -17,38 +17,6 @@ def test_prod_numpy16_bug(self):
 
         assert not isinstance(result, Series)
 
-    def test_dot(self):
-        a = Series(np.random.randn(4), index=["p", "q", "r", "s"])
-        b = DataFrame(
-            np.random.randn(3, 4), index=["1", "2", "3"], columns=["p", "q", "r", "s"]
-        ).T
-
-        result = a.dot(b)
-        expected = Series(np.dot(a.values, b.values), index=["1", "2", "3"])
-        tm.assert_series_equal(result, expected)
-
-        # Check index alignment
-        b2 = b.reindex(index=reversed(b.index))
-        result = a.dot(b)
-        tm.assert_series_equal(result, expected)
-
-        # Check ndarray argument
-        result = a.dot(b.values)
-        assert np.all(result == expected.values)
-        tm.assert_almost_equal(a.dot(b["2"].values), expected["2"])
-
-        # Check series argument
-        tm.assert_almost_equal(a.dot(b["1"]), expected["1"])
-        tm.assert_almost_equal(a.dot(b2["1"]), expected["1"])
-
-        msg = r"Dot product shape mismatch, \(4,\) vs \(3,\)"
-        # exception raised is of type Exception
-        with pytest.raises(Exception, match=msg):
-            a.dot(a.values[:3])
-        msg = "matrices are not aligned"
-        with pytest.raises(ValueError, match=msg):
-            a.dot(b.T)
-
     def test_matmul(self):
         # matmul test is for GH #10259
         a = Series(np.random.randn(4), index=["p", "q", "r", "s"])