add Cert.__repr__ to ease debugging

mitmproxy/certs.py

@@ -49,6 +49,9 @@ class Cert(serializable.Serializable):
     def __eq__(self, other):
         return self.fingerprint() == other.fingerprint()
 
+    def __repr__(self):
+        return f"<Cert(cn={self.cn!r}, altnames={self.altnames!r})>"
+
     @classmethod
     def from_state(cls, state):
         return cls.from_pem(state)

test/mitmproxy/test_certs.py

@@ -180,6 +180,7 @@ class TestCert:
         assert c2.issuer
         assert c2.to_pem()
         assert c2.has_expired() is not None
+        assert repr(c2) == "<Cert(cn='www.inode.co.nz', altnames=['www.inode.co.nz', 'inode.co.nz'])>"
 
         assert c1 != c2