Class: RuboCop::Cop::RSpec::BeEql

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

Overview

Check for expectations where ‘be(…)` can replace `eql(…)`.

The ‘be` matcher compares by identity while the `eql` matcher compares using `eql?`. Integers, floats, booleans, symbols, and nil can be compared by identity and therefore the `be` matcher is preferable as it is a more strict test.

This cop only looks for instances of ‘expect(…).to eql(…)`. We do not check `to_not` or `not_to` since `!eql?` is more strict than `!equal?`. We also do not try to flag `eq` because if `a == b`, and `b` is comparable by identity, `a` is still not necessarily the same type as `b` since the `#==` operator can coerce objects for comparison.

Examples:

# bad
expect(foo).to eql(1)
expect(foo).to eql(1.0)
expect(foo).to eql(true)
expect(foo).to eql(false)
expect(foo).to eql(:bar)
expect(foo).to eql(nil)

# good
expect(foo).to be(1)
expect(foo).to be(1.0)
expect(foo).to be(true)
expect(foo).to be(false)
expect(foo).to be(:bar)
expect(foo).to be(nil)

Constant Summary collapse

MSG = 
'Prefer `be` over `eql`.'
RESTRICT_ON_SEND = 
%i[to].freeze

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

#eql_type_with_identity(node) ⇒ Object 



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# File 'lib/rubocop/cop/rspec/be_eql.rb', line 47

def_node_matcher :eql_type_with_identity, <<~PATTERN
  (send _ :to $(send nil? :eql {true false int float sym nil}))
PATTERN

#on_send(node) ⇒ Object 



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# File 'lib/rubocop/cop/rspec/be_eql.rb', line 51

def on_send(node)
  eql_type_with_identity(node) do |eql|
    add_offense(eql.loc.selector) do |corrector|
      corrector.replace(eql.loc.selector, 'be')
    end
  end
end