add correctly failing tests

Author: sneakers-the-rat

tests/test_interface/test_numpy.py

@@ -1,6 +1,10 @@
+from datetime import datetime
+
 import numpy as np
 import pytest
+from pydantic import BaseModel
 
+from numpydantic import NDArray, Shape
 from numpydantic.testing.cases import NumpyCase
 
 pytestmark = pytest.mark.numpy
@@ -18,6 +22,29 @@ def test_numpy_dtype(dtype_cases):
     dtype_cases.validate_case()
 
 
+@pytest.mark.dtype
+def test_numpy_datetime64():
+    """
+    Special testing for datetime64, since it's a numpy-specific thing,
+    and requires special handling in the other interfaces.
+
+    Typically, we expect that generic type annotation to be a `datetime.datetime`,
+    but it should also be possible to use a numpy.datetime64 type when doing
+    numpy validation.
+
+    So this test is just the simplest regression test to make sure we can use datetime64
+    """
+    arr = np.array([np.datetime64(datetime.now())], dtype=np.datetime64)
+
+    annotation = NDArray[Shape["*"], np.datetime64]
+    _ = annotation(arr)
+
+    class MyModel(BaseModel):
+        array: annotation
+
+    _ = MyModel(array=arr)
+
+
 def test_numpy_coercion(model_blank):
     """If no other interface matches, we try and coerce to a numpy array"""
     instance = model_blank(array=[1, 2, 3])