FormatChecker.__repr__

This could use attrs, but probably some day checkers will
become a pyrsistent.pmap, and we can do that then.

2 files changed, 13 insertions, 0 deletions

diff --git a/jsonschema/_format.py b/jsonschema/_format.py
index d3f1345..51b9b50 100644
--- a/jsonschema/_format.py
+++ b/jsonschema/_format.py
@@ -39,6 +39,9 @@ class FormatChecker(object):
         else:
             self.checkers = dict((k, self.checkers[k]) for k in formats)
 
+    def __repr__(self):
+        return "<FormatChecker checkers={}>".format(sorted(self.checkers))
+
     def checks(self, format, raises=()):
         """
         Register a decorated function as validating a new format.
diff --git a/jsonschema/tests/test_format.py b/jsonschema/tests/test_format.py
index e9e5f99..14512c5 100644
--- a/jsonschema/tests/test_format.py
+++ b/jsonschema/tests/test_format.py
@@ -78,3 +78,13 @@ class TestFormatChecker(TestCase):
         checker = FormatChecker()
         with self.assertRaises(FormatError):
             checker.check(instance="not-an-ipv4", format="ipv4")
+
+    def test_repr(self):
+        checker = FormatChecker(formats=())
+        checker.checks("foo")(lambda thing: True)
+        checker.checks("bar")(lambda thing: True)
+        checker.checks("baz")(lambda thing: True)
+        self.assertEqual(
+            repr(checker),
+            "<FormatChecker checkers=['bar', 'baz', 'foo']>",
+        )