For example, when I use gomock to test code that uses DynamoDB, like this:

    mockDynamoDB := awsmock.NewMockDynamoDBAPI(ctrl)
    mockDynamoDBClient.EXPECT().PutItemWithContext(gomock.Any(),
       gomock.Any() // Here I should use a custom matcher for comparing PutItemInput
).Return(&dynamodb.PutItemOutput{...}, nil).Times(1)

   // do something which will internally call PutItemWithContext

To avoid using gomock.Any() everywhere, I think I should implement a matcher for PutItemInput, however it seems a bit difficult as the PutItemInput is complex with serialized Item map[string]*AttributeValue, I need to compare one by one like this but I don’t like this implementation.

func (piim dynamodbPutItemInputEqualMatcher) Matches(x interface{}) bool {
    input, ok := x.(*dynamodb.PutItemInput)
    if !ok {
        return false
    }

    if input.TableName != nil && piim.expectedInput.TableName != nil && *input.TableName != *pie.expectedInput.TableName {
        return false
    }

    for attributeName, attributeValue := range input.Item {
        exptectedAttributeValue, ok := piim.expectedInput.Item[attributeName]
        if !ok {
            return false
        }

        if attributeValue.N != nil && exptectedAttributeValue.N != nil && *attributeValue.N != *exptectedAttributeValue.N {
            return false
        }
        if attributeValue.S != nil && exptectedAttributeValue.S != nil && *attributeValue.S != *exptectedAttributeValue.S {
            return false
        }
        if attributeValue.BOOL != nil && exptectedAttributeValue.BOOL != nil && *attributeValue.BOOL != *exptectedAttributeValue.BOOL {
            return false
        }
        if attributeValue.NULL != nil && exptectedAttributeValue.NULL != nil && *attributeValue.NULL != *exptectedAttributeValue.NULL {
            return false
        }

        if attributeValue.B != nil || attributeValue.NS != nil || attributeValue.SS != nil || attributeValue.BS != nil || attributeValue.L != nil || attributeValue.M != nil {
            return false
        }
    }

    return true
}

Also DynamoDB has other APIs like GetItem, ScanPages, etc,. I need to implement custom matcher for every type of input struct.

Do we have a better way to use gomock with AWS? Thanks.