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 object and attribute as arguments to the matcher or passing a block that reads the attribute value.

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

Examples:

‘EnforcedStyle: block`

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

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

‘EnforcedStyle: method_call`

# 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 }

Constant Summary collapse

MSG_BLOCK = 
'Prefer `change(%<obj>s, :%<attr>s)`.'
MSG_CALL = 
'Prefer `change { %<obj>s.%<attr>s }`.'
RESTRICT_ON_SEND = 
%i[change].freeze

Instance Method Summary collapse

Methods inherited from Base

inherited, #on_new_investigation

Methods included from RSpec::Language::NodePattern

#block_pattern, #send_pattern

Methods included from RSpec::Language

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

Instance Method Details

#expect_change_with_arguments(node) ⇒ Object 



41
42
43
 
# File 'lib/rubocop/cop/rspec/expect_change.rb', line 41

def_node_matcher :expect_change_with_arguments, <<-PATTERN
  (send nil? :change $_ (sym $_))
PATTERN

#expect_change_with_block(node) ⇒ Object 



46
47
48
49
50
51
52
 
# File 'lib/rubocop/cop/rspec/expect_change.rb', line 46

def_node_matcher :expect_change_with_block, <<-PATTERN
  (block
    (send nil? :change)
    (args)
    (send ({const send} nil? $_) $_)
  )
PATTERN

#on_block(node) ⇒ Object 



66
67
68
69
70
71
72
73
74
75
76
 
# File 'lib/rubocop/cop/rspec/expect_change.rb', line 66

def on_block(node)
  return unless style == :method_call

  expect_change_with_block(node) do |receiver, message|
    msg = format(MSG_BLOCK, obj: receiver, attr: message)
    add_offense(node, message: msg) do |corrector|
      replacement = "change(#{receiver}, :#{message})"
      corrector.replace(node, replacement)
    end
  end
end

#on_send(node) ⇒ Object 



54
55
56
57
58
59
60
61
62
63
64
 
# File 'lib/rubocop/cop/rspec/expect_change.rb', line 54

def on_send(node)
  return unless style == :block

  expect_change_with_arguments(node) do |receiver, message|
    msg = format(MSG_CALL, obj: receiver.source, attr: message)
    add_offense(node, message: msg) do |corrector|
      replacement = "change { #{receiver.source}.#{message} }"
      corrector.replace(node, replacement)
    end
  end
end