Unexpected Method Call

Start with the reported mockDynamo.PutItem implementation and its ExpectPutItem helper, then reproduce the failure in TestInvokeEvents using the shown dynamodb.PutItemInput. Compare the expected and actual values, especially the proto.Marshal bytes in the B field, and verify the result against testify's argument-matching behavior. Done means explaining why equivalent-looking calls differ and identifying a reliable matching behavior.

I'm trying to mock PutItem(*dynamodb.PutItemInput) from AWS Dynamo Package GoDoc here

However, I'm running into a bunch of problems that look something like this:

--- FAIL: TestInvokeEvents (0.00s)
panic:

mock: Unexpected Method Call
-----------------------------

PutItem(*dynamodb.PutItemInput)
		0: {
  Item: {
    account#user: {
      S: "2#b396abf06c7264027a0a2d037d5ccc25"
    },
    time#name#id: {
      S: "1642501880#pageView#9c7e33a0-9a2f-4372-b5bf-ef20a9995d29"
    },
    proto_message: {
      B: <binary> len 348
    }
  },
  TableName: "test_table"
}

The closest call I have is:

PutItem(*dynamodb.PutItemInput)
		0: {
  Item: {
    account#user: {
      S: "2#b396abf06c7264027a0a2d037d5ccc25"
    },
    time#name#id: {
      S: "1642501880#pageView#9c7e33a0-9a2f-4372-b5bf-ef20a9995d29"
    },
    proto_message: {
      B: <binary> len 348
    }
  },
  TableName: "test_table"
}


 [recovered]
	panic:

I've tried a couple of things:

• Check for types:

func (md *mockDynamo) PutItem(input *dynamodb.PutItemInput) (*dynamodb.PutItemOutput, error) {
	args := md.Called(input)
	return args.Get(0).(*dynamodb.PutItemOutput), args.Error(1)
}

func (db *mockDynamo) ExpectPutItem(putItemInput *dynamodb.PutItemInput, putItemOutput *dynamodb.PutItemOutput, withErr error) {
	db.On("PutItem", putItemInput).Return(putItemOutput, withErr).Once()
}

• Removed the .Once() to make sure it's not being called multiple times..

What I've found after debugging this for about 5-6 hours is that the issue seemed to be near the B: <binary> len 348, which is the bytes result coming from proto.Marshal, removing the bytes from being included in the object resulted in the type passing.
Currently I've been able to workaround the issue by using mock.Anything, however it would be great to know as to why this is even happening!

Much appreciated and looking forward to chasing this down!
-- Robin