diff --git a/.changes/next-release/feature-protocol-2b945450.json b/.changes/next-release/feature-protocol-2b945450.json
new file mode 100644
index 0000000000..3e50b1e941
--- /dev/null
+++ b/.changes/next-release/feature-protocol-2b945450.json
@@ -0,0 +1,5 @@
+{
+  "type": "feature",
+  "category": "protocol",
+  "description": "Update protocol tests"
+}
\ No newline at end of file
diff --git a/test/fixtures/protocol/input/rest-json.json b/test/fixtures/protocol/input/rest-json.json
index 293b4bfc30..d18b7b9043 100644
--- a/test/fixtures/protocol/input/rest-json.json
+++ b/test/fixtures/protocol/input/rest-json.json
@@ -1620,5 +1620,148 @@
         }
       }
     ]
+  },
+  {
+    "description": "Union trait",
+    "metadata": {
+      "protocol": "rest-json",
+      "apiVersion": "2014-01-01"
+    },
+    "shapes": {
+      "InputShape": {
+        "type": "structure",
+        "members": {
+          "OneOf": {"shape": "MyUnion"}
+        }
+      },
+      "MyUnion": {
+        "type": "structure",
+        "union": true,
+        "members": {
+          "a": {"shape": "StringType"},
+          "b": {"shape": "StringType"},
+          "c": {"shape": "Struct"},
+          "d": {"shape": "Struct"},
+          "e": {"shape": "ComplexList"}
+        }
+      },
+      "StringType": {
+        "type": "string"
+      },
+      "Struct": {
+        "type": "structure",
+        "members": {
+          "hello": {"shape": "StringType"}
+        }
+      },
+      "ComplexList": {
+        "type": "list",
+        "member": {"shape": "Struct"}
+      }
+    },
+    "cases": [
+      {
+        "given": {
+          "input": {
+            "shape": "InputShape"
+          },
+          "http": {
+            "method": "POST"
+          },
+          "name": "OperationName"
+        },
+        "params": {
+          "OneOf": {"a": "hi"}
+        },
+        "serialized": {
+          "uri": "/",
+          "body": "{\"OneOf\": {\"a\": \"hi\"}}"
+        }
+      },
+      {
+        "given": {
+          "input": {
+            "shape": "InputShape"
+          },
+          "http": {
+            "method": "POST"
+          },
+          "name": "OperationName"
+        },
+        "params": {
+          "OneOf": {"b": "hi"}
+        },
+        "serialized": {
+          "uri": "/",
+          "body": "{\"OneOf\": {\"b\": \"hi\"}}"
+        }
+      },
+      {
+        "given": {
+          "input": {
+            "shape": "InputShape"
+          },
+          "http": {
+            "method": "POST"
+          },
+          "name": "OperationName"
+        },
+        "params": {
+          "OneOf": {
+            "c": {
+              "hello": "hi"
+            }
+          }
+        },
+        "serialized": {
+          "uri": "/",
+          "body": "{\"OneOf\": {\"c\": {\"hello\": \"hi\"}}}"
+        }
+      },
+      {
+        "given": {
+          "input": {
+            "shape": "InputShape"
+          },
+          "http": {
+            "method": "POST"
+          },
+          "name": "OperationName"
+        },
+        "params": {
+          "OneOf": {
+            "d": {
+              "hello": "hi"
+            }
+          }
+        },
+        "serialized": {
+          "uri": "/",
+          "body": "{\"OneOf\": {\"d\": {\"hello\": \"hi\"}}}"
+        }
+      },
+      {
+        "given": {
+          "input": {
+            "shape": "InputShape"
+          },
+          "http": {
+            "method": "POST"
+          },
+          "name": "OperationName"
+        },
+        "params": {
+          "OneOf": {
+            "e": [
+              {"hello": "hi"}
+            ]
+          }
+        },
+        "serialized": {
+          "uri": "/",
+          "body": "{\"OneOf\": {\"e\": [{\"hello\": \"hi\"}]}}"
+        }
+      }
+    ]
   }
 ]
diff --git a/test/fixtures/protocol/output/ec2.json b/test/fixtures/protocol/output/ec2.json
index f2a25dc3e3..bbef7ef9d5 100644
--- a/test/fixtures/protocol/output/ec2.json
+++ b/test/fixtures/protocol/output/ec2.json
@@ -567,5 +567,92 @@
         }
       }
     ]
+  },
+  {
+    "description": "Modeled exceptions",
+    "metadata": {
+      "protocol": "ec2"
+    },
+    "shapes": {
+      "ExceptionShape": {
+        "type": "structure",
+        "members": {
+          "Status": {
+            "shape": "StatusShape",
+            "location": "statusCode"
+          },
+          "BodyMember": {
+            "shape": "StringType"
+          },
+          "Message": {
+            "shape": "StringType"
+          }
+        }
+      },
+      "OtherExceptionShape": {
+        "BodyMember": {
+          "shape": "StringType"
+        }
+      },
+      "StatusShape": {
+        "type": "integer"
+      },
+      "StringType": {
+        "type": "string"
+      }
+    },
+    "cases": [
+      {
+        "given": {
+          "errors": [
+            {"shape": "ExceptionShape"}
+          ],
+          "name": "OperationName"
+        },
+        "error": {
+          "Status": 400,
+          "BodyMember": "mybody",
+          "Message": "mymessage"
+        },
+        "errorCode": "ExceptionShape",
+        "errorMessage": "mymessage",
+        "response": {
+          "status_code": 400,
+          "headers": {},
+          "body": "<Response><Errors><Error><Code>ExceptionShape</Code><Message>mymessage</Message><BodyMember>mybody</BodyMember></Error></Errors></Response>"
+        }
+      },
+      {
+        "given": {
+          "errors": [
+            {"shape": "ExceptionShape"}
+          ],
+          "name": "OperationName"
+        },
+        "error": {},
+        "errorCode": "OtherExceptionShape",
+        "errorMessage": "mymessage",
+        "response": {
+          "status_code": 400,
+          "headers": {},
+          "body": "<Response><Errors><Error><Code>OtherExceptionShape</Code><Message>mymessage</Message><BodyMember>mybody</BodyMember></Error></Errors></Response>"
+        }
+      },
+      {
+        "given": {
+          "errors": [
+            {"shape": "ExceptionShape"}
+          ],
+          "name": "OperationName"
+        },
+        "error": {},
+        "errorCode": "UndefinedShape",
+        "response": {
+          "status_code": 400,
+          "headers": {},
+          "body": "<Response><Errors><Error><Code>UndefinedShape</Code><BodyMember>mybody</BodyMember></Error></Errors></Response>"
+        }
+      }
+    ]
   }
 ]
diff --git a/test/fixtures/protocol/output/json.json b/test/fixtures/protocol/output/json.json
index 9b70b80e48..521ec6acce 100644
--- a/test/fixtures/protocol/output/json.json
+++ b/test/fixtures/protocol/output/json.json
@@ -431,5 +431,151 @@
         }
       }
     ]
+  },
+  {
+    "description": "Modeled exceptions",
+    "metadata": {
+      "protocol": "json"
+    },
+    "shapes": {
+      "ExceptionShape": {
+        "type": "structure",
+        "members": {
+          "Status": {
+            "shape": "StatusShape",
+            "location": "statusCode"
+          },
+          "BodyMember": {
+            "shape": "StringType"
+          },
+          "Code": {
+            "shape": "StringType"
+          },
+          "Message": {
+            "shape": "StringType"
+          }
+        }
+      },
+      "OtherExceptionShape": {
+        "BodyMember": {
+          "shape": "StringType"
+        }
+      },
+      "StatusShape": {
+        "type": "integer"
+      },
+      "StringType": {
+        "type": "string"
+      }
+    },
+    "cases": [
+      {
+        "given": {
+          "errors": [
+            {"shape": "ExceptionShape"}
+          ],
+          "name": "OperationName"
+        },
+        "error": {
+          "Status": 400,
+          "BodyMember": "mybody",
+          "Code": "OtherExceptionShape",
+          "Message": "mymessage"
+        },
+        "errorCode": "ExceptionShape",
+        "errorMessage": "mymessage",
+        "response": {
+          "status_code": 400,
+          "headers": {},
+          "body": "{ \"__type\": \"ExceptionShape\", \"Code\": \"OtherExceptionShape\", \"BodyMember\": \"mybody\", \"Message\": \"mymessage\"}"
+        }
+      },
+      {
+        "given": {
+          "errors": [
+            {"shape": "ExceptionShape"}
+          ],
+          "name": "OperationName"
+        },
+        "error": {},
+        "errorCode": "OtherExceptionShape",
+        "errorMessage": "mymessage",
+        "response": {
+          "status_code": 400,
+          "headers": {},
+          "body": "{ \"__type\": \"OtherExceptionShape\", \"Code\": \"ExceptionShape\", \"BodyMember\": \"mybody\", \"Message\": \"mymessage\"}"
+        }
+      },
+      {
+        "given": {
+          "errors": [
+            {"shape": "ExceptionShape"}
+          ],
+          "name": "OperationName"
+        },
+        "error": {},
+        "errorCode": "UndefinedShape",
+        "response": {
+          "status_code": 400,
+          "headers": {
+            "ImaHeader": "test",
+            "X-Foo": "abc"
+          },
+          "body": "{ \"__type\": \"UndefinedShape\", \"Code\": \"ExceptionShape\", \"BodyMember\": \"mybody\"}"
+        }
+      }
+    ]
+  },
+  {
+    "description": "Modeled exceptions with jsonVersion 1.0",
+    "metadata": {
+      "protocol": "json",
+      "jsonVersion": "1.0"
+    },
+    "shapes": {
+      "ExceptionShape": {
+        "type": "structure",
+        "members": {
+          "Status": {
+            "shape": "StatusShape",
+            "location": "statusCode"
+          },
+          "BodyMember": {
+            "shape": "StringType"
+          },
+          "Message": {
+            "shape": "StringType"
+          }
+        }
+      },
+      "StatusShape": {
+        "type": "integer"
+      },
+      "StringType": {
+        "type": "string"
+      }
+    },
+    "cases": [
+      {
+        "given": {
+          "errors": [
+            {"shape": "ExceptionShape"}
+          ],
+          "name": "OperationName"
+        },
+        "error": {
+          "Status": 400,
+          "BodyMember": "mybody",
+          "Message": "mymessage"
+        },
+        "errorCode": "ExceptionShape",
+        "errorMessage": "mymessage",
+        "response": {
+          "status_code": 400,
+          "headers": {},
+          "body": "{ \"__type\": \"FooPrefix#ExceptionShape\", \"BodyMember\": \"mybody\", \"Message\": \"mymessage\"}"
+        }
+      }
+    ]
   }
 ]
diff --git a/test/fixtures/protocol/output/query.json b/test/fixtures/protocol/output/query.json
index a2fd3a52ed..02963cf992 100644
--- a/test/fixtures/protocol/output/query.json
+++ b/test/fixtures/protocol/output/query.json
@@ -889,5 +889,92 @@
         }
       }
     ]
+  },
+  {
+    "description": "Modeled exceptions",
+    "metadata": {
+      "protocol": "query"
+    },
+    "shapes": {
+      "ExceptionShape": {
+        "type": "structure",
+        "members": {
+          "Status": {
+            "shape": "StatusShape",
+            "location": "statusCode"
+          },
+          "BodyMember": {
+            "shape": "StringType"
+          },
+          "Message": {
+            "shape": "StringType"
+          }
+        }
+      },
+      "OtherExceptionShape": {
+        "BodyMember": {
+          "shape": "StringType"
+        }
+      },
+      "StatusShape": {
+        "type": "integer"
+      },
+      "StringType": {
+        "type": "string"
+      }
+    },
+    "cases": [
+      {
+        "given": {
+          "errors": [
+            {"shape": "ExceptionShape"}
+          ],
+          "name": "OperationName"
+        },
+        "error": {
+          "Status": 400,
+          "BodyMember": "mybody",
+          "Message": "mymessage"
+        },
+        "errorCode": "ExceptionShape",
+        "errorMessage": "mymessage",
+        "response": {
+          "status_code": 400,
+          "headers": {},
+          "body": "<ErrorResponse><Error><Type>SomeType</Type><Code>ExceptionShape</Code><Message>mymessage</Message><BodyMember>mybody</BodyMember></Error></ErrorResponse>"
+        }
+      },
+      {
+        "given": {
+          "errors": [
+            {"shape": "ExceptionShape"}
+          ],
+          "name": "OperationName"
+        },
+        "error": {},
+        "errorCode": "OtherExceptionShape",
+        "errorMessage": "mymessage",
+        "response": {
+          "status_code": 400,
+          "headers": {},
+          "body": "<ErrorResponse><Error><Type>SomeType</Type><Code>OtherExceptionShape</Code><Message>mymessage</Message><BodyMember>mybody</BodyMember></Error></ErrorResponse>"
+        }
+      },
+      {
+        "given": {
+          "errors": [
+            {"shape": "ExceptionShape"}
+          ],
+          "name": "OperationName"
+        },
+        "error": {},
+        "errorCode": "UndefinedShape",
+        "response": {
+          "status_code": 400,
+          "headers": {},
+          "body": "<ErrorResponse><Error><Type>SomeType</Type><Code>UndefinedShape</Code><BodyMember>mybody</BodyMember></Error></ErrorResponse>"
+        }
+      }
+    ]
   }
 ]
diff --git a/test/fixtures/protocol/output/rest-json.json b/test/fixtures/protocol/output/rest-json.json
index 7f2badddaa..c98b641802 100644
--- a/test/fixtures/protocol/output/rest-json.json
+++ b/test/fixtures/protocol/output/rest-json.json
@@ -733,6 +733,34 @@
           "headers": {},
           "body": "{\"BodyListField\":[\"{\\\"Foo\\\":\\\"Bar\\\"}\"]}"
         }
+      },
+      {
+        "given": {
+          "output": {
+            "shape": "OutputShape"
+          },
+          "name": "OperationName"
+        },
+        "result": {
+          "HeaderField": {"Foo":{}}
+        },
+        "response": {
+          "status_code": 200,
+          "headers": {"X-Amz-Foo": "e30="}
+        }
+      },
+      {
+        "given": {
+          "output": {
+            "shape": "OutputShape"
+          },
+          "name": "OperationName"
+        },
+        "result": {},
+        "response": {
+          "status_code": 200,
+          "headers": {"X-Amz-Foo": ""}
+        }
       }
     ]
   },
@@ -815,5 +843,331 @@
         }
       }
     ]
+  },
+  {
+    "description": "Modeled exceptions",
+    "metadata": {
+      "protocol": "rest-json"
+    },
+    "shapes": {
+      "ExceptionShape": {
+        "type": "structure",
+        "members": {
+          "ImaHeader": {
+            "shape": "HeaderShape"
+          },
+          "ImaHeaderLocation": {
+            "shape": "HeaderShape",
+            "locationName": "X-Foo"
+          },
+          "Status": {
+            "shape": "StatusShape",
+            "location": "statusCode"
+          },
+          "BodyMember": {
+            "shape": "StringType"
+          },
+          "Message": {
+            "shape": "StringType"
+          }
+        }
+      },
+      "OtherExceptionShape": {
+        "BodyMember": {
+          "shape": "StringType"
+        }
+      },
+      "HeaderShape": {
+        "type": "string",
+        "location": "header"
+      },
+      "StatusShape": {
+        "type": "integer"
+      },
+      "StringType": {
+        "type": "string"
+      }
+    },
+    "cases": [
+      {
+        "given": {
+          "errors": [
+            {"shape": "ExceptionShape"}
+          ],
+          "name": "OperationName"
+        },
+        "error": {
+          "ImaHeader": "test",
+          "ImaHeaderLocation": "abc",
+          "Status": 400,
+          "BodyMember": "mybody",
+          "Message": "mymessage"
+        },
+        "errorCode": "ExceptionShape",
+        "errorMessage": "mymessage",
+        "response": {
+          "status_code": 400,
+          "headers": {
+            "ImaHeader": "test",
+            "X-Foo": "abc",
+            "X-Amzn-Errortype": "ExceptionShape"
+          },
+          "body": "{\"BodyMember\": \"mybody\", \"Message\": \"mymessage\"}"
+        }
+      },
+      {
+        "given": {
+          "errors": [
+            {"shape": "ExceptionShape"}
+          ],
+          "name": "OperationName"
+        },
+        "error": {
+          "ImaHeader": "test",
+          "ImaHeaderLocation": "abc",
+          "Status": 400,
+          "BodyMember": "mybody",
+          "Message": "mymessage"
+        },
+        "errorCode": "ExceptionShape",
+        "errorMessage": "mymessage",
+        "response": {
+          "status_code": 400,
+          "headers": {
+            "ImaHeader": "test",
+            "X-Foo": "abc"
+          },
+          "body": "{ \"code\": \"ExceptionShape\", \"BodyMember\": \"mybody\", \"Message\": \"mymessage\"}"
+        }
+      },
+      {
+        "given": {
+          "errors": [
+            {"shape": "ExceptionShape"}
+          ],
+          "name": "OperationName"
+        },
+        "error": {
+          "ImaHeader": "test",
+          "ImaHeaderLocation": "abc",
+          "Status": 400,
+          "BodyMember": "mybody",
+          "Message": "mymessage"
+        },
+        "errorCode": "ExceptionShape",
+        "errorMessage": "mymessage",
+        "response": {
+          "status_code": 400,
+          "headers": {
+            "ImaHeader": "test",
+            "X-Foo": "abc",
+            "X-Amzn-Errortype": "ExceptionShape"
+          },
+          "body": "{ \"code\": \"OtherExceptionShape\", \"BodyMember\": \"mybody\", \"Message\": \"mymessage\"}"
+        }
+      },
+      {
+        "given": {
+          "errors": [
+            {"shape": "ExceptionShape"}
+          ],
+          "name": "OperationName"
+        },
+        "error": {},
+        "errorCode": "OtherExceptionShape",
+        "errorMessage": "mymessage",
+        "response": {
+          "status_code": 400,
+          "headers": {
+            "ImaHeader": "test",
+            "X-Foo": "abc",
+            "X-Amzn-Errortype": "OtherExceptionShape"
+          },
+          "body": "{ \"BodyMember\": \"mybody\", \"Message\": \"mymessage\"}"
+        }
+      },
+      {
+        "given": {
+          "errors": [
+            {"shape": "ExceptionShape"}
+          ],
+          "name": "OperationName"
+        },
+        "error": {},
+        "errorCode": "OtherExceptionShape",
+        "errorMessage": "mymessage",
+        "response": {
+          "status_code": 400,
+          "headers": {
+            "ImaHeader": "test",
+            "X-Foo": "abc"
+          },
+          "body": "{ \"code\": \"OtherExceptionShape\", \"BodyMember\": \"mybody\", \"Message\": \"mymessage\"}"
+        }
+      },
+      {
+        "given": {
+          "errors": [
+            {"shape": "ExceptionShape"}
+          ],
+          "name": "OperationName"
+        },
+        "error": {},
+        "errorCode": "UndefinedShape",
+        "response": {
+          "status_code": 400,
+          "headers": {
+            "ImaHeader": "test",
+            "X-Foo": "abc",
+            "X-Amzn-Errortype": "UndefinedShape"
+          },
+          "body": "{ \"BodyMember\": \"mybody\"}"
+        }
+      },
+      {
+        "given": {
+          "errors": [
+            {"shape": "ExceptionShape"}
+          ],
+          "name": "OperationName"
+        },
+        "error": {},
+        "errorCode": "UndefinedShape",
+        "response": {
+          "status_code": 400,
+          "headers": {
+            "ImaHeader": "test",
+            "X-Foo": "abc"
+          },
+          "body": "{ \"code\": \"UndefinedShape\", \"BodyMember\": \"mybody\"}"
+        }
+      }
+    ]
+  },
+  {
+    "description": "Unions",
+    "metadata": {
+      "protocol": "rest-json"
+    },
+    "shapes": {
+      "OutputShape": {
+        "type": "structure",
+        "members": {
+          "OneOf": {
+            "shape": "MyUnion"
+          }
+        }
+      },
+      "MyUnion": {
+        "type": "structure",
+        "union": true,
+        "members": {
+          "a": {"shape": "StringType"},
+          "b": {"shape": "StringType"},
+          "c": {"shape": "Struct"},
+          "d": {"shape": "Struct"},
+          "e": {"shape": "ComplexList"}
+        }
+      },
+      "StringType": {
+        "type": "string"
+      },
+      "Struct": {
+        "type": "structure",
+        "members": {
+          "hello": {"shape": "StringType"}
+        }
+      },
+      "ComplexList": {
+        "type": "list",
+        "member": {"shape": "Struct"}
+      }
+    },
+    "cases": [
+      {
+        "given": {
+          "output": {
+            "shape": "OutputShape"
+          },
+          "name": "OperationName"
+        },
+        "result": {
+          "OneOf": {"a": "hi"}
+        },
+        "response": {
+          "status_code": 200,
+          "headers": {},
+          "body": "{\"OneOf\": {\"a\": \"hi\"}}"
+        }
+      },
+      {
+        "given": {
+          "output": {
+            "shape": "OutputShape"
+          },
+          "name": "OperationName"
+        },
+        "result": {
+          "OneOf": {"b": "hi"}
+        },
+        "response": {
+          "status_code": 200,
+          "headers": {},
+          "body": "{\"OneOf\": {\"b\": \"hi\"}}"
+        }
+      },
+      {
+        "given": {
+          "output": {
+            "shape": "OutputShape"
+          },
+          "name": "OperationName"
+        },
+        "result": {
+          "OneOf": {"c": {"hello": "hi"}}
+        },
+        "response": {
+          "status_code": 200,
+          "headers": {},
+          "body": "{\"OneOf\": {\"c\": {\"hello\": \"hi\"}}}"
+        }
+      },
+      {
+        "given": {
+          "output": {
+            "shape": "OutputShape"
+          },
+          "name": "OperationName"
+        },
+        "result": {
+          "OneOf": {"d": {"hello": "hi"}}
+        },
+        "response": {
+          "status_code": 200,
+          "headers": {},
+          "body": "{\"OneOf\": {\"d\": {\"hello\": \"hi\"}}}"
+        }
+      },
+      {
+        "given": {
+          "output": {
+            "shape": "OutputShape"
+          },
+          "name": "OperationName"
+        },
+        "result": {
+          "OneOf": {
+            "e": [
+              {"hello": "hi"}
+            ]
+          }
+        },
+        "response": {
+          "status_code": 200,
+          "headers": {},
+          "body": "{\"OneOf\": {\"e\": [{\"hello\": \"hi\"}]}}"
+        }
+      }
+    ]
   }
 ]
diff --git a/test/fixtures/protocol/output/rest-xml.json b/test/fixtures/protocol/output/rest-xml.json
index 0260b915ca..385a30e6ae 100644
--- a/test/fixtures/protocol/output/rest-xml.json
+++ b/test/fixtures/protocol/output/rest-xml.json
@@ -968,5 +968,117 @@
         }
       }
     ]
+  },
+  {
+    "description": "Modeled exceptions",
+    "metadata": {
+      "protocol": "rest-xml"
+    },
+    "shapes": {
+      "ExceptionShape": {
+        "type": "structure",
+        "members": {
+          "ImaHeader": {
+            "shape": "HeaderShape"
+          },
+          "ImaHeaderLocation": {
+            "shape": "HeaderShape",
+            "locationName": "X-Foo"
+          },
+          "Status": {
+            "shape": "StatusShape",
+            "location": "statusCode"
+          },
+          "BodyMember": {
+            "shape": "StringType"
+          },
+          "Message": {
+            "shape": "StringType"
+          }
+        }
+      },
+      "OtherExceptionShape": {
+        "BodyMember": {
+          "shape": "StringType"
+        }
+      },
+      "HeaderShape": {
+        "type": "string",
+        "location": "header"
+      },
+      "StatusShape": {
+        "type": "integer"
+      },
+      "StringType": {
+        "type": "string"
+      }
+    },
+    "cases": [
+      {
+        "given": {
+          "errors": [
+            {"shape": "ExceptionShape"}
+          ],
+          "name": "OperationName"
+        },
+        "error": {
+          "ImaHeader": "test",
+          "ImaHeaderLocation": "abc",
+          "Status": 400,
+          "BodyMember": "mybody",
+          "Message": "mymessage"
+        },
+        "errorCode": "ExceptionShape",
+        "errorMessage": "mymessage",
+        "response": {
+          "status_code": 400,
+          "headers": {
+            "ImaHeader": "test",
+            "X-Foo": "abc",
+            "X-Amzn-Requestid": "foo-id"
+          },
+          "body": "<ErrorResponse><Error><Type>SomeType</Type><Code>ExceptionShape</Code><Message>mymessage</Message><BodyMember>mybody</BodyMember></Error></ErrorResponse>"
+        }
+      },
+      {
+        "given": {
+          "errors": [
+            {"shape": "ExceptionShape"}
+          ],
+          "name": "OperationName"
+        },
+        "error": {},
+        "errorCode": "OtherExceptionShape",
+        "errorMessage": "mymessage",
+        "response": {
+          "status_code": 400,
+          "headers": {
+            "ImaHeader": "test",
+            "X-Foo": "abc",
+            "X-Amzn-Requestid": "foo-id"
+          },
+          "body": "<ErrorResponse><Error><Type>SomeType</Type><Code>OtherExceptionShape</Code><Message>mymessage</Message><BodyMember>mybody</BodyMember></Error></ErrorResponse>"
+        }
+      },
+      {
+        "given": {
+          "errors": [
+            {"shape": "ExceptionShape"}
+          ],
+          "name": "OperationName"
+        },
+        "error": {},
+        "errorCode": "UndefinedShape",
+        "response": {
+          "status_code": 400,
+          "headers": {
+            "ImaHeader": "test",
+            "X-Foo": "abc",
+            "X-Amzn-Requestid": "foo-id"
+          },
+          "body": "<ErrorResponse><Error><Type>SomeType</Type><Code>UndefinedShape</Code><BodyMember>mybody</BodyMember></Error></ErrorResponse>"
+        }
+      }
+    ]
   }
 ]
diff --git a/test/protocol/protocol.spec.js b/test/protocol/protocol.spec.js
index abfe281a10..77b088e8f8 100644
--- a/test/protocol/protocol.spec.js
+++ b/test/protocol/protocol.spec.js
@@ -125,9 +125,11 @@
     expectedData = formatData(_case.result, svc.api.operations[_case.op].output);
     resultData = formatData(req.response.data, svc.api.operations[_case.op].output);
     results = [];
-    for (k in expectedData) {
-      v = expectedData[k];
-      results.push(expect(resultData[k]).to.eql(v));
+    if (resultData) {
+      for (k in expectedData) {
+        v = expectedData[k];
+        results.push(expect(resultData[k]).to.eql(v));
+      }
     }
     return results;
   };