Class: RuboCop::Cop::RSpec::ExpectChange

Inherits:
Base
  • Object
show all
Extended by:
AutoCorrector
Includes:
ConfigurableEnforcedStyle
Defined in:
lib/rubocop/cop/rspec/expect_change.rb

Overview

Checks for consistent style of change matcher.

Enforces either passing a receiver and message as method arguments, or a block.

This cop can be configured using the ‘EnforcedStyle` option.

When using compound expectations with ‘change` and a negated matcher (e.g., `not_change`), you can configure the `NegatedMatcher` option to ensure consistent style enforcement across both matchers.

Examples:

‘EnforcedStyle: method_call` (default)

# bad
expect { run }.to change { Foo.bar }
expect { run }.to change { foo.baz }

# good
expect { run }.to change(Foo, :bar)
expect { run }.to change(foo, :baz)
# also good when there are arguments or chained method calls
expect { run }.to change { Foo.bar(:count) }
expect { run }.to change { user.reload.name }

‘EnforcedStyle: block`

# bad
expect { run }.to change(Foo, :bar)

# good
expect { run }.to change { Foo.bar }

‘NegatedMatcher: not_change` (with compound expectations)

# bad
expect { run }.to change(Foo, :bar).and not_change { Foo.baz }

# good
expect { run }.to change(Foo, :bar).and not_change(Foo, :baz)

Constant Summary collapse

MSG_BLOCK = 
'Prefer `%<matcher>s(%<obj>s, :%<attr>s)`.'
MSG_CALL = 
'Prefer `%<matcher>s { %<obj>s.%<attr>s }`.'

Instance Method Summary collapse

Methods inherited from Base

inherited, #on_new_investigation

Methods included from RSpec::Language

#example?, #example_group?, #example_group_with_body?, #explicit_rspec?, #hook?, #include?, #let?, #rspec?, #shared_group?, #spec_group?, #subject?

Instance Method Details

#expect_matcher_with_arguments(node) ⇒ Object 



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# File 'lib/rubocop/cop/rspec/expect_change.rb', line 70

def_node_matcher :expect_matcher_with_arguments, <<~PATTERN
  (send nil? _ $_ ({sym str} $_))
PATTERN

#expect_matcher_with_block(node) ⇒ Object 



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# File 'lib/rubocop/cop/rspec/expect_change.rb', line 75

def_node_matcher :expect_matcher_with_block, <<~PATTERN
  (block
    (send nil? _)
    (args)
    (send
      ${
        (send nil? _)  # change { user.name }
        const          # change { User.count }
      }
      $_
    )
  )
PATTERN

#on_block(node) ⇒ Object

rubocop:disable InternalAffairs/NumblockHandler, InternalAffairs/ItblockHandler



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# File 'lib/rubocop/cop/rspec/expect_change.rb', line 104

def on_block(node) # rubocop:disable InternalAffairs/NumblockHandler, InternalAffairs/ItblockHandler
  return unless style == :method_call
  return unless matcher_method?(node.method_name)

  expect_matcher_with_block(node) do |receiver, message|
    matcher_name = node.method_name.to_s
    msg = format(MSG_BLOCK, matcher: matcher_name,
                            obj: receiver.source, attr: message)
    add_offense(node, message: msg) do |corrector|
      replacement = "#{matcher_name}(#{receiver.source}, :#{message})"
      corrector.replace(node, replacement)
    end
  end
end

#on_send(node) ⇒ Object 



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# File 'lib/rubocop/cop/rspec/expect_change.rb', line 89

def on_send(node)
  return unless style == :block
  return unless matcher_method?(node.method_name)

  expect_matcher_with_arguments(node) do |receiver, message|
    matcher_name = node.method_name.to_s
    msg = format(MSG_CALL, matcher: matcher_name,
                           obj: receiver.source, attr: message)
    add_offense(node, message: msg) do |corrector|
      replacement = "#{matcher_name} { #{receiver.source}.#{message} }"
      corrector.replace(node, replacement)
    end
  end
end