Add tests for dtype keyword

Author: antonwolfy

dpnp/tests/test_fft.py

@@ -411,22 +411,35 @@ def test_fft_error(self, xp):
         assert_raises(IndexError, xp.fft.fft2, a)
 
 
+@pytest.mark.parametrize("func", ["fftfreq", "rfftfreq"])
 class TestFftfreq:
-    @pytest.mark.parametrize("func", ["fftfreq", "rfftfreq"])
     @pytest.mark.parametrize("n", [10, 20])
     @pytest.mark.parametrize("d", [0.5, 2])
     def test_fftfreq(self, func, n, d):
-        expected = getattr(dpnp.fft, func)(n, d)
-        result = getattr(numpy.fft, func)(n, d)
-        assert_dtype_allclose(expected, result)
+        result = getattr(dpnp.fft, func)(n, d)
+        expected = getattr(numpy.fft, func)(n, d)
+        assert_dtype_allclose(result, expected)
 
-    @pytest.mark.parametrize("func", ["fftfreq", "rfftfreq"])
-    def test_error(self, func):
-        # n should be an integer
-        assert_raises(ValueError, getattr(dpnp.fft, func), 10.0)
+    @pytest.mark.parametrize("dt", [None] + get_float_dtypes())
+    def test_dtype(self, func, dt):
+        n = 15
+        result = getattr(dpnp.fft, func)(n, dtype=dt)
+        expected = getattr(numpy.fft, func)(n).astype(dt)
+        assert_dtype_allclose(result, expected)
 
-        # d should be an scalar
-        assert_raises(ValueError, getattr(dpnp.fft, func), 10, (2,))
+    def test_error(self, func):
+        func = getattr(dpnp.fft, func)
+        # n must be an integer
+        assert_raises(ValueError, func, 10.0)
+
+        # d must be an scalar
+        assert_raises(ValueError, func, 10, (2,))
+
+        # dtype must be None or a real-valued floating-point dtype
+        # which is passed as a keyword argument only
+        assert_raises(TypeError, func, 10, 2, None)
+        assert_raises(ValueError, func, 10, 2, dtype=dpnp.intp)
+        assert_raises(ValueError, func, 10, 2, dtype=dpnp.complex64)
 
 
 class TestFftn: