Make offense locations of metrics cops to contain whole a method

[pocke]

Problem

Currently, metrics cops add an offence for a complex method to def keyword.
For example, Metrics/AbcSize

Inspecting 1 file
C

Offenses:

test.rb:1:1: C: Assignment Branch Condition size for complex is too high. [1.41/1]
def complex
^^^

1 file inspected, 1 offense detected

However, the "def" is not complex, the method body is complex.
So I think this cop should add an offence whole the method.

Note: Metrics/MethodLength already adds offences whole the method.

Solution

Make offense locations of metrics cops to contain whole a method.
AbcSize, CyclomaticComplexity and PerceivedComplexity cops are targets of this change.

For example

Inspecting 1 file
C

Offenses:

test.rb:1:1: C: Assignment Branch Condition size for complex is too high. [1.41/1]
def complex ...
^^^^^^^^^^^

1 file inspected, 1 offense detected

Note

Our spec helper does not support multi line offences completely. But we have a workaround for multi line offences, we can write an annotation after first line of an offence to test the offence that is for multi-line.
For example:

expect_offense(<<-RUBY)
  def foo
  ^^^^^^^ message
    bar
  end
RUBY

---

Before submitting the PR make sure the following are checked:

• Wrote good commit messages.
• Commit message starts with [Fix #issue-number] (if the related issue exists).
• Used the same coding conventions as the rest of the project.
• Feature branch is up-to-date with master (if not - rebase it).
• Squashed related commits together.
• Added tests.
• Added an entry to the Changelog if the new code introduces user-observable changes. See changelog entry format.
• All tests(rake spec) are passing.
• The new code doesn't generate RuboCop offenses that are checked by rake internal_investigation.
• The PR relates to only one subject with a clear title
  and description in grammatically correct, complete sentences.
• Updated cop documentation with rake generate_cops_documentation (required only when you've added a new cop or changed the configuration/documentation of an existing cop).

[garettarrowood]

Makes sense and looks good to me.

[bbatsov]

Solid improvement! 👍