Fixed Deadline comparison methods, improved tests

grpclib/metadata.py

@@ -43,10 +43,16 @@ class Deadline:
         self._timestamp = _timestamp
 
     def __lt__(self, other):
-        return self._timestamp < other.timestamp
+        if not isinstance(other, Deadline):
+            raise TypeError('comparison is not supported between '
+                            'instances of \'{}\' and \'{}\''
+                            .format(type(self).__name__, type(other).__name__))
+        return self._timestamp < other._timestamp
 
     def __eq__(self, other):
-        return self._timestamp == other.timestamp
+        if not isinstance(other, Deadline):
+            return False
+        return self._timestamp == other._timestamp
 
     @classmethod
     def from_metadata(cls, metadata):

tests/test_metadata.py

@@ -33,7 +33,16 @@ def test_decode_timeout(value, expected):
 
 
 def test_deadline():
-    assert min(Deadline(1), Deadline(2)) == Deadline(1)
+    assert Deadline.from_timeout(1) < Deadline.from_timeout(2)
+
+    with pytest.raises(TypeError) as err:
+        Deadline.from_timeout(1) < 'invalid'
+    err.match('comparison is not supported between instances '
+              'of \'Deadline\' and \'str\'')
+
+    assert Deadline(_timestamp=1) == Deadline(_timestamp=1)
+
+    assert Deadline.from_timeout(1) != 'invalid'
 
 
 def test_headers_with_deadline():