BUG-23224 Add tests and other requested changes

Author: JustinZhengBC

pandas/core/arrays/integer.py

@@ -172,14 +172,12 @@ def coerce_to_array(values, dtype, mask=None, copy=False):
     values = np.array(values, copy=copy)
     if is_object_dtype(values):
         inferred_type = infer_dtype(values)
-        if inferred_type not in ['floating', 'integer',
-                                 'mixed-integer', 'mixed-integer-float']:
-            if inferred_type is 'mixed' and all(isna(x) for x in values):
-                values = np.array([np.nan] * len(values))  # GH 23224
-            else:
-                raise TypeError(
-                    "{} cannot be converted to an IntegerDtype".format(
-                        values.dtype))
+        if inferred_type is 'mixed' and isna(values).any():
+            values = np.array([np.nan] * len(values))  # GH 23224
+        elif inferred_type not in ['floating', 'integer',
+                                   'mixed-integer', 'mixed-integer-float']:
+            raise TypeError("{} cannot be converted to an IntegerDtype".format(
+                values.dtype))
 
     elif not (is_integer_dtype(values) or is_float_dtype(values)):
         raise TypeError("{} cannot be converted to an IntegerDtype".format(

pandas/tests/arrays/test_integer.py

@@ -519,7 +519,8 @@ def test_integer_array_constructor_copy():
         1,
         1.0,
         pd.date_range('20130101', periods=2),
-        np.array(['foo'])])
+        np.array(['foo']),
+        [[1, 2], [3, 4]]])
 def test_to_integer_array_error(values):
     # error in converting existing arrays to IntegerArrays
     with pytest.raises(TypeError):
@@ -564,7 +565,8 @@ def test_to_integer_array_float():
     'result, expected',
     [
         (integer_array([None]), integer_array([np.nan])),
-        (integer_array([None, np.nan]), integer_array([np.nan, np.nan]))])
+        (integer_array([None, np.nan]), integer_array([np.nan, np.nan])),
+        (integer_array([np.nan, np.nan]), integer_array([np.nan, np.nan]))])
 def test_to_integer_array_none(result, expected):
     tm.assert_extension_array_equal(result, expected)