test/auth: add another bcrypt max len test

This time the other way around just to be extra sure. Radicale currently
does not ever call bcrypt.hashpw, let alone with an overlong password.

Related-to: #1896
Signed-off-by: Henning Schild <henning@hennsch.de>

radicale/tests/test_auth.py

@@ -191,6 +191,21 @@ class TestBaseAuthRequests(BaseTest):
         hash = bcrypt.hashpw(("a" * self.BCRYPT_MAX_PWLEN).encode(), bcrypt.gensalt())
         self._test_htpasswd("bcrypt", "tmp:" + hash.decode('utf-8'), m)
 
+    @pytest.mark.skipif(has_bcrypt == 0, reason="No bcrypt module installed")
+    @pytest.mark.skipif(not utils.passlib_libpass_supports_bcrypt()[0], reason="bcrypt module incompatible with passlib(libpass) module")
+    def test_bcrypt_hash_long(self) -> None:
+        import bcrypt
+        salt = bcrypt.gensalt()
+        h0 = bcrypt.hashpw(("a" * self.BCRYPT_MAX_PWLEN).encode(), salt)
+        try:
+            h1 = bcrypt.hashpw(("a" * (self.BCRYPT_MAX_PWLEN + 1)).encode(), salt)
+        # bcrypt >= 5, truncated for us
+        except ValueError:
+            return
+
+        # overlong password produced same hash as maxlen
+        assert h0 == h1
+
     @pytest.mark.skipif(has_argon2 == 0, reason="No argon2 module installed")
     def test_htpasswd_argon2_i(self) -> None:
         self._test_htpasswd("argon2", "tmp:$argon2i$v=19$m=65536,t=3,p=4$NgZg7F1rzRkDoNSaMwag9A$qmsvMKEn5zOXHm8e3O5fKzzcRo0UESwaDr/cETe5YPI")