TST: Better handle np.array_equal() edge cases

pandas/src/testing.pyx

@@ -82,10 +82,12 @@ cpdef assert_almost_equal(a, b, bint check_less_precise=False):
         assert na == nb, (
             "Length of two iterators not the same: %r != %r" % (na, nb)
         )
-        if (isinstance(a, np.ndarray) and
-                isinstance(b, np.ndarray) and
-                np.array_equal(a, b)):
-            return True
+        if isinstance(a, np.ndarray) and isinstance(b, np.ndarray):
+            try:
+                if np.array_equal(a, b):
+                    return True
+            except:
+                pass
         else:
             for i in xrange(na):
                 assert_almost_equal(a[i], b[i], check_less_precise)

pandas/tests/test_testing.py

@@ -48,6 +48,12 @@ def test_assert_almost_equal_numbers_with_mixed(self):
         self._assert_not_almost_equal_both(1, [1,])
         self._assert_not_almost_equal_both(1, object())
 
+    def test_assert_almost_equal_edge_case_ndarrays(self):
+        self._assert_almost_equal_both(np.array([], dtype='M8[ns]'),
+                                       np.array([], dtype='float64'))
+        self._assert_almost_equal_both(np.array([], dtype=str),
+                                       np.array([], dtype='int64'))
+
     def test_assert_almost_equal_dicts(self):
         self._assert_almost_equal_both({'a': 1, 'b': 2}, {'a': 1, 'b': 2})
 

pandas/util/testing.py

@@ -411,9 +411,9 @@ def assert_series_equal(left, right, check_dtype=True,
                         check_less_precise=False):
     if check_series_type:
         assert_isinstance(left, type(right))
-    assert_almost_equal(left.values, right.values, check_less_precise)
     if check_dtype:
         assert_attr_equal('dtype', left, right)
+    assert_almost_equal(left.values, right.values, check_less_precise)
     if check_less_precise:
         assert_almost_equal(
             left.index.values, right.index.values, check_less_precise)