Improve matmul/_contract coverage (#908)

tests/integration/test_matmul.py

@@ -147,19 +147,23 @@ def test_out_invalid_shape_DIVERGENCE(self):
         out = num.zeros(shape)
         num.matmul(A, B, out=out)
 
-    def test_out_invalid_dtype(self):
+    @pytest.mark.parametrize(
+        ("dtype", "out_dtype", "casting"),
+        ((None, np.int64, "same_kind"), (float, str, "safe")),
+        ids=("direct", "intermediate"),
+    )
+    def test_out_invalid_dtype(self, dtype, out_dtype, casting):
         expected_exc = TypeError
-        A_np = num.ones((3, 2, 4))
-        B_np = num.ones((3, 4, 3))
+        A_np = np.ones((3, 2, 4))
+        B_np = np.ones((3, 4, 3))
         A_num = num.ones((3, 2, 4))
         B_num = num.ones((3, 4, 3))
-        dtype = np.int64
-        out_np = np.zeros((3, 2, 3), dtype=dtype)
-        out_num = num.zeros((3, 2, 3), dtype=dtype)
+        out_np = np.zeros((3, 2, 3), dtype=out_dtype)
+        out_num = num.zeros((3, 2, 3), dtype=out_dtype)
         with pytest.raises(expected_exc):
-            np.matmul(A_np, B_np, out=out_np)
+            np.matmul(A_np, B_np, dtype=dtype, out=out_np, casting=casting)
         with pytest.raises(expected_exc):
-            num.matmul(A_num, B_num, out=out_num)
+            num.matmul(A_num, B_num, dtype=dtype, out=out_num, casting=casting)
 
     @pytest.mark.parametrize(
         "casting_dtype",
@@ -183,18 +187,20 @@ def test_invalid_casting_dtype(self, casting_dtype):
         with pytest.raises(expected_exc):
             num.matmul(A_num, B_num, casting=casting, dtype=dtype)
 
-    @pytest.mark.xfail
-    def test_invalid_casting(self):
-        # In Numpy, raise ValueError
-        # In cuNumeric, pass
+    @pytest.mark.parametrize(
+        "dtype", (str, pytest.param(float, marks=pytest.mark.xfail)), ids=str
+    )
+    def test_invalid_casting(self, dtype):
         expected_exc = ValueError
         casting = "unknown"
         A_np = np.ones((2, 4))
-        B_np = np.ones((4, 3))
+        B_np = np.ones((4, 3), dtype=dtype)
         A_num = num.ones((2, 4))
-        B_num = num.ones((4, 3))
+        B_num = num.ones((4, 3), dtype=dtype)
+        # In Numpy, raise ValueError
         with pytest.raises(expected_exc):
             np.matmul(A_np, B_np, casting=casting)
+        # cuNumeric does not check casting when A and B are of the same dtype
         with pytest.raises(expected_exc):
             num.matmul(A_num, B_num, casting=casting)