diff --git a/googleapiclient/http.py b/googleapiclient/http.py
index cd2775a..4125666 100644
--- a/googleapiclient/http.py
+++ b/googleapiclient/http.py
@@ -1760,16 +1760,18 @@
         connection_type=None,
     ):
         resp, content = self._iterable.pop(0)
-        if content == "echo_request_headers":
+        content = six.ensure_binary(content)
+
+        if content == b"echo_request_headers":
             content = headers
-        elif content == "echo_request_headers_as_json":
+        elif content == b"echo_request_headers_as_json":
             content = json.dumps(headers)
-        elif content == "echo_request_body":
+        elif content == b"echo_request_body":
             if hasattr(body, "read"):
                 content = body.read()
             else:
                 content = body
-        elif content == "echo_request_uri":
+        elif content == b"echo_request_uri":
             content = uri
         if isinstance(content, six.text_type):
             content = content.encode("utf-8")
diff --git a/googleapiclient/model.py b/googleapiclient/model.py
index 554056e..7255ecf 100644
--- a/googleapiclient/model.py
+++ b/googleapiclient/model.py
@@ -218,7 +218,7 @@
                 return self.no_content_response
             return self.deserialize(content)
         else:
-            LOGGER.debug("Content from bad request was: %s" % content)
+            LOGGER.debug("Content from bad request was: %r" % content)
             raise HttpError(resp, content)
 
     def serialize(self, body_value):