Add unit test for --no-ensure-ascii option
diff --git a/tests/pretty_format_json_test.py b/tests/pretty_format_json_test.py
index 7bfc31f..62e37f1 100644
--- a/tests/pretty_format_json_test.py
+++ b/tests/pretty_format_json_test.py
@@ -20,6 +20,7 @@
 @pytest.mark.parametrize(('filename', 'expected_retval'), (
     ('not_pretty_formatted_json.json', 1),
     ('unsorted_pretty_formatted_json.json', 1),
+    ('non_ascii_pretty_formatted_json.json', 1),
     ('pretty_formatted_json.json', 0),
 ))
 def test_pretty_format_json(filename, expected_retval):
@@ -30,6 +31,7 @@
 @pytest.mark.parametrize(('filename', 'expected_retval'), (
     ('not_pretty_formatted_json.json', 1),
     ('unsorted_pretty_formatted_json.json', 0),
+    ('non_ascii_pretty_formatted_json.json', 1),
     ('pretty_formatted_json.json', 0),
 ))
 def test_unsorted_pretty_format_json(filename, expected_retval):
@@ -40,6 +42,7 @@
 @pytest.mark.parametrize(('filename', 'expected_retval'), (
     ('not_pretty_formatted_json.json', 1),
     ('unsorted_pretty_formatted_json.json', 1),
+    ('non_ascii_pretty_formatted_json.json', 1),
     ('pretty_formatted_json.json', 1),
     ('tab_pretty_formatted_json.json', 0),
 ))
@@ -48,6 +51,11 @@
     assert ret == expected_retval
 
 
+def test_non_ascii_pretty_format_json():
+    ret = pretty_format_json(['--no-ensure-ascii', get_resource_path('non_ascii_pretty_formatted_json.json')])
+    assert ret == 0
+
+
 def test_autofix_pretty_format_json(tmpdir):
     srcfile = tmpdir.join('to_be_json_formatted.json')
     shutil.copyfile(