Add test for DateTime#blank?

[kenta-s]

Currently there are no tests for DateTime#blank?
Even after I make the method return true as an experiment, all the tests were passed :P

[rails-bot]

r? @pixeltrix

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[simi]

Can be test_blank?.

[kenta-s]

@simi thank you :)

[pixeltrix]

@kenta-s are there equivalent tests for Date and ActiveSupport::TimeWithZone ?

[kenta-s]

No, I couldn't find them. Let me add them as well :)

[kenta-s]

@pixeltrix done :)

[rafaelfranca]

Do those classes implement #blank? explicitly or are them relying in the Object#blank? implementation?

[kenta-s]

Those methods are implemented explicitly.

https://github.com/rails/rails/blob/master/activesupport/lib/active_support/core_ext/date/blank.rb#L9
https://github.com/rails/rails/blob/master/activesupport/lib/active_support/core_ext/date_time/blank.rb#L9
https://github.com/rails/rails/blob/master/activesupport/lib/active_support/time_with_zone.rb#L425