TST: Add tests for np.floating.is_integer

Author: Bas van Beek

numpy/core/tests/test_scalar_methods.py

@@ -102,3 +102,25 @@ def test_roundtrip(self, ftype, frac_vals, exp_vals):
                 pytest.skip("longdouble too small on this platform")
 
             assert_equal(nf / df, f, "{}/{}".format(n, d))
+
+
+@pytest.mark.parametrize("code", np.typecodes["Float"])
+class TestIsInteger:
+    @pytest.mark.parametrize("str_value", ["inf", "nan"])
+    def test_special(self, code: str, str_value: str) -> None:
+        cls = np.dtype(code).type
+        value = cls(str_value)
+        assert not value.is_integer()
+
+    def test_true(self, code: str) -> None:
+        float_array = np.arange(-5, 5).astype(code)
+        for value in float_array:
+            assert value.is_integer()
+
+    def test_false(self, code: str) -> None:
+        float_array = np.arange(-5, 5).astype(code)
+        float_array *= 1.1
+        for value in float_array:
+            if value == 0:
+                continue
+            assert not value.is_integer()

numpy/typing/tests/data/fail/scalars.py

@@ -87,7 +87,6 @@ def func(a: np.float32) -> None: ...
 
 c8.__getnewargs__()  # E: Invalid self argument
 f2.__getnewargs__()  # E: Invalid self argument
-f2.is_integer()  # E: Invalid self argument
 f2.hex()  # E: Invalid self argument
 np.float16.fromhex("0x0.0p+0")  # E: Invalid self argument
 f2.__trunc__()  # E: Invalid self argument