Include a Cop to enforce assert_nil over assert_equal(nil)

[duduribeiro]

Hey folks 👋

This commit adds a Cop that checks some usage of
assert_equal(nil, something) and enforces the usage of
assert_nil(something) instead.

I don't know if the cop that I wrote is right and maybe it needs some adjustment 😂

I also needed to copy some code from the rubocop gem itself, because the matchers itself relies on RSpec. Maybe we can change it in rubocop gem to share part of the code that can be reusable, and add the matchers for rspec and minitest.

[koic]

I also needed to copy some code from the rubocop gem itself, because the matchers itself relies on RSpec.

Awesome work! It ’s a great first step. We can hack in the future based on the code base. 👍

[koic]

Can you add the setting of this cop to config/default.yml? The following is an example and let's set VersionAdded: '0.1.0'.
https://github.com/rubocop-hq/rubocop-rails/blob/v2.3.0/config/default.yml#L58-L61

[duduribeiro]

hey @koic 👋

I did update the code with the suggested changes.

I changed the node_matcher pattern to capture the argument: https://github.com/rubocop-hq/rubocop-minitest/pull/6/files#diff-4e8bec16638093f13a99617349303b4bR18

can you check if it is valid? thanks so much!

☕️

[koic]

The def_node_matcher pattern looks good, but false positives occur when writing a message to assert_equal.

assert_equal(nil, actual, 'message')

https://github.com/seattlerb/minitest/blob/ab39d35fb4e84eb866ed9c4ecb707cbf3889de42/lib/minitest/assertions.rb#L192

[duduribeiro]

hey @koic 👋

I updated the code. WDYT with the changes ?

thanks

☕️

[duduribeiro]

hey @koic, I did apply your changes, can you review? thanks so much

[bbatsov]

@duduribeiro I see all tests are failing due to passing the wrong number of arguments to one method.

[duduribeiro]

@bbatsov and @koic I rebased with master and it fixed.. thanks

[duduribeiro]

@koic I updated the code

[duduribeiro]

hey @koic 👋

I changed the node pattern to allow message to be a variable and a constant and also allowing the method call. Can you check please?

thanks so much ☕️

[duduribeiro]

@koic I changed with your suggestions. Thanks so much

[koic]

Many thanks for your great work!

[duduribeiro]

@koic thanks for your help!

[koic]

@bbatsov I'd like to release RuboCop Minitest 0.1.0 after merging this PR and maintaining some documentation. This cop is the first cop that will be published on RuboCop Minitest.
This is a great achievement by @duduribeiro.

[bbatsov]

@koic I completely agree. Let's make this happen. 😄