[Fix rubocop#60] Add new cop Minitest/GlobalExpectations

To check against deprecated global expectations. These will be removed
in Minitest 6.

Closes rubocop#60

CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## master (unreleased)
 
+### New features
+
+* [#60](https:/rubocop-hq/rubocop-minitest/pull/60): Add new cop `Minitest/GlobalExpectations` to check for deprecated global expectations. ([@tejasbubane][])
+
 ### Bug fixes
 
 * [#58](https:/rubocop-hq/rubocop-minitest/pull/58): Fix a false negative for `Minitest/AssertMatch` and `Minitest/RefuteMatch` when an argument is enclosed in redundant parentheses. ([@koic][])

config/default.yml

@@ -56,6 +56,11 @@ Minitest/AssertTruthy:
  Enabled: true
  VersionAdded: '0.2'
 
+Minitest/GlobalExpectations:
+ Description: 'This cop checks for deprecated global expectations.'
+ Enabled: true
+ VersionAdded: '0.7'
+
 Minitest/RefuteEmpty:
  Description: 'This cop enforces to use `refute_empty` instead of using `refute(object.empty?)`.'
  StyleGuide: 'https:/rubocop-hq/minitest-style-guide#refute-empty'

lib/rubocop/cop/minitest/global_expectations.rb

@@ -0,0 +1,74 @@
+# frozen_string_literal: true
+
+module RuboCop
+ module Cop
+ module Minitest
+ # This Cop checks for deprecated global expectations
+ # and autocorrects them to use expect format.
+ #
+ # @example
+ # # bad
+ # n.must_equal 42
+ # n.wont_match b
+ #
+ # # good
+ # _(n).must_equal 42
+ # _(n).wont_match b
+ class GlobalExpectations < Cop
+ MSG = 'Prefer using `%<corrected>s`.'
+
+ VALUE_MATCHERS = %i[
+ be be_close_to be_empty be_instance_of be_kind_of
+ be_nil be_same_as be_silent be_within_epsilon equal
+ include match respond_to must_exist
+ ].map do |matcher|
+ [:"must_#{matcher}", :"wont_#{matcher}"]
+ end.flatten.freeze
+
+ BLOCK_MATCHERS = %i[must_output must_raise must_throw].freeze
+
+ MATCHERS_STR = (VALUE_MATCHERS + BLOCK_MATCHERS).map do |m|
+ ":#{m}"
+ end.join(' ').freeze
+
+ def_node_matcher :global_expectation?, <<~PATTERN
+ (send (send _ _) {#{MATCHERS_STR}} ...)
+ PATTERN
+
+ def on_send(node)
+ return unless global_expectation?(node)
+
+ message = format(MSG, corrected: correct_suggestion(node))
+ add_offense(node, message: message)
+ end
+
+ def autocorrect(node)
+ return unless global_expectation?(node)
+
+ lambda do |corrector|
+ receiver = node.receiver.loc.selector
+
+ if BLOCK_MATCHERS.include?(node.method_name)
+ corrector.insert_before(receiver, '_ { ')
+ corrector.insert_after(receiver, ' }')
+ else
+ corrector.insert_before(receiver, '_(')
+ corrector.insert_after(receiver, ')')
+ end
+ end
+ end
+
+ private
+
+ def correct_suggestion(node)
+ source = node.receiver.source
+ if BLOCK_MATCHERS.include?(node.method_name)
+ node.source.sub(source, "_ { #{source} }")
+ else
+ node.source.sub(source, "_(#{source})")
+ end
+ end
+ end
+ end
+ end
+end

lib/rubocop/cop/minitest_cops.rb

@@ -11,6 +11,7 @@
 require_relative 'minitest/assert_match'
 require_relative 'minitest/assert_respond_to'
 require_relative 'minitest/assert_truthy'
+require_relative 'minitest/global_expectations'
 require_relative 'minitest/refute_empty'
 require_relative 'minitest/refute_false'
 require_relative 'minitest/refute_equal'

manual/cops.md

@@ -10,6 +10,7 @@
 * [Minitest/AssertNil](cops_minitest.md#minitestassertnil)
 * [Minitest/AssertRespondTo](cops_minitest.md#minitestassertrespondto)
 * [Minitest/AssertTruthy](cops_minitest.md#minitestasserttruthy)
+* [Minitest/GlobalExpectations](cops_minitest.md#minitestglobalexpectations)
 * [Minitest/RefuteEmpty](cops_minitest.md#minitestrefuteempty)
 * [Minitest/RefuteEqual](cops_minitest.md#minitestrefuteequal)
 * [Minitest/RefuteFalse](cops_minitest.md#minitestrefutefalse)

manual/cops_minitest.md

@@ -220,6 +220,27 @@ assert(actual, 'message')
 
 * [https:/rubocop-hq/minitest-style-guide#assert-truthy](https:/rubocop-hq/minitest-style-guide#assert-truthy)
 
+## Minitest/GlobalExpectations
+
+Enabled by default | Safe | Supports autocorrection | VersionAdded | VersionChanged
+--- | --- | --- | --- | ---
+Enabled | Yes | Yes | 0.7 | -
+
+This Cop checks for deprecated global expectations
+and autocorrects them to use expect format.
+
+### Examples
+
+```ruby
+# bad
+n.must_equal 42
+n.wont_match b
+
+# good
+_(n).must_equal 42
+_(n).wont_match b
+```
+
 ## Minitest/RefuteEmpty
 
 Enabled by default | Safe | Supports autocorrection | VersionAdded | VersionChanged

test/rubocop/cop/minitest/global_expectations_test.rb

@@ -0,0 +1,64 @@
+# frozen_string_literal: true
+
+require 'test_helper'
+
+class GlobalExpectationsTest < Minitest::Test
+ RuboCop::Cop::Minitest::GlobalExpectations::VALUE_MATCHERS.each do |matcher|
+ define_method(:"test_registers_offense_when_using_global_#{matcher}") do
+ assert_offense(<<~RUBY)
+ it 'does something' do
+ n.#{matcher} 42
+ #{'^' * (matcher.length + 5)} Prefer using `_(n).#{matcher} 42`.
+ end
+ RUBY
+
+ assert_correction(<<~RUBY)
+ it 'does something' do
+ _(n).#{matcher} 42
+ end
+ RUBY
+ end
+
+ define_method(:"test_no_offense_when_using_expect_form_of_#{matcher}") do
+ assert_no_offenses(<<~RUBY)
+ it 'does something' do
+ _(n).#{matcher} 42
+ end
+ RUBY
+ end
+ end
+
+ def test_works_with_chained_method_calls
+ assert_offense(<<~RUBY)
+ it 'does something' do
+ A.foo.bar.must_equal 42
+ ^^^^^^^^^^^^^^^^^^^^^^^ Prefer using `_(A.foo.bar).must_equal 42`.
+ end
+ RUBY
+ end
+
+ RuboCop::Cop::Minitest::GlobalExpectations::BLOCK_MATCHERS.each do |matcher|
+ define_method(:"test_registers_offense_when_using_global_#{matcher}") do
+ assert_offense(<<~RUBY)
+ it 'does something' do
+ n.#{matcher} 42
+ #{'^' * (matcher.length + 5)} Prefer using `_ { n }.#{matcher} 42`.
+ end
+ RUBY
+
+ assert_correction(<<~RUBY)
+ it 'does something' do
+ _ { n }.#{matcher} 42
+ end
+ RUBY
+ end
+
+ define_method(:"test_no_offense_when_using_expect_form_of_#{matcher}") do
+ assert_no_offenses(<<~RUBY)
+ it 'does something' do
+ _ { n }.#{matcher} 42
+ end
+ RUBY
+ end
+ end
+end