bpo-24641: Improved error message for JSON unserializible keys. (#4364)

Also updated an example for default() in the module docstring.
Removed quotes around type name in other error messages.

1 files changed, 8 insertions, 5 deletions

diff --git a/Lib/test/test_json/test_fail.py b/Lib/test/test_json/test_fail.py
index 7910521..eb9064e 100644
--- a/Lib/test/test_json/test_fail.py
+++ b/Lib/test/test_json/test_fail.py
@@ -93,12 +93,15 @@ class TestFail:
 
     def test_non_string_keys_dict(self):
         data = {'a' : 1, (1, 2) : 2}
+        with self.assertRaisesRegex(TypeError,
+                'keys must be str, int, float, bool or None, not tuple'):
+            self.dumps(data)
 
-        #This is for c encoder
-        self.assertRaises(TypeError, self.dumps, data)
-
-        #This is for python encoder
-        self.assertRaises(TypeError, self.dumps, data, indent=True)
+    def test_not_serializable(self):
+        import sys
+        with self.assertRaisesRegex(TypeError,
+                'Object of type module is not JSON serializable'):
+            self.dumps(sys)
 
     def test_truncated_input(self):
         test_cases = [