import numpy as np

a = np.timedelta64(1, "ns")
b = np.timedelta64(1, "ns")

np.testing.assert_allclose(a, b)

Traceback (most recent call last):
  File "c:/Users/shh/Development/pressoh/timedelta_assert.py", line 6, in <module>
    np.testing.assert_allclose(a, b)
  File "C:\Users\shh\miniconda3\envs\pressoh_dev\lib\site-packages\numpy\testing\_private\utils.py", line 1529, in assert_allclose
    verbose=verbose, header=header, equal_nan=equal_nan)
  File "C:\Users\shh\miniconda3\envs\pressoh_dev\lib\site-packages\numpy\testing\_private\utils.py", line 790, in assert_array_compare
    val = comparison(x, y)
  File "C:\Users\shh\miniconda3\envs\pressoh_dev\lib\site-packages\numpy\testing\_private\utils.py", line 1524, in compare
    equal_nan=equal_nan)
  File "<__array_function__ internals>", line 6, in isclose
  File "C:\Users\shh\miniconda3\envs\pressoh_dev\lib\site-packages\numpy\core\numeric.py", line 2354, in isclose
    dt = multiarray.result_type(y, 1.)
  File "<__array_function__ internals>", line 6, in result_type
TypeError: The DTypes <class 'numpy.dtype[float64]'> and <class 'numpy.dtype[timedelta64]'> do not have a common DType. For example they cannot be stored in a single array unless the dtype is `object`.