Add Bad Request Exception For Empty Rule

[Amoncy]

#3474
Hi Eric,

I have made the changes to the code. Could you please review?

Thank you

[EricWittmann]

Good start, but a few changes are needed I think.

This endpoint accepts a payload that contains two values: 1. the name/type of the rule and 2. the configuration value of the rule

Looking at this now I see that we should be checking for null for the name/type and we should be checking for null or empty-string for the config.

You can use requireParameter() to check the name/type, but will need to check for null value or empty string for the config. Note that you must check for null value first because if you check for empty value (like you are doing now) but it's actually null that will result in a NullPointerException.

For both values we should throw a MissingRequiredParameterException in case of failure.

[carlesarnal]

In addition to what Eric said we should add a test to validate the new behaviour and ensure that the expected exception is thrown.