Check that decimal and non-decimal returns 'mixed'

Author: margaret

pandas/tests/dtypes/test_inference.py

@@ -469,6 +469,10 @@ def test_decimals(self):
         result = lib.infer_dtype(arr)
         assert result == 'decimal'
 
+        arr = np.array([1.0, 2.0, Decimal(3)])
+        result = lib.infer_dtype(arr)
+        assert result == 'mixed'
+
     def test_string(self):
         pass