unfreeze_string_spec.rb

# frozen_string_literal: true

RSpec.describe RuboCop::Cop::Performance::UnfreezeString, :config do
  it 'registers an offense and corrects for an empty string with `.dup`' do
    expect_offense(<<~RUBY)
      "".dup
      ^^^^^^ Use unary plus to get an unfrozen string literal.
    RUBY

    expect_correction(<<~RUBY)
      +""
    RUBY
  end

  it 'registers an offense and corrects for a string with `.dup`' do
    expect_offense(<<~RUBY)
      "foo".dup
      ^^^^^^^^^ Use unary plus to get an unfrozen string literal.
    RUBY

    expect_correction(<<~RUBY)
      +"foo"
    RUBY
  end

  it 'registers an offense and corrects for a heredoc with `.dup`' do
    expect_offense(<<~RUBY)
      <<TEXT.dup
      ^^^^^^^^^^ Use unary plus to get an unfrozen string literal.
        foo
        bar
      TEXT
    RUBY

    expect_correction(<<~RUBY)
      +<<TEXT
        foo
        bar
      TEXT
    RUBY
  end

  it 'registers an offense and corrects for a string that contains a string' \
     'interpolation with `.dup`' do
    expect_offense(<<~'RUBY')
      "foo#{bar}baz".dup
      ^^^^^^^^^^^^^^^^^^ Use unary plus to get an unfrozen string literal.
    RUBY

    expect_correction(<<~'RUBY')
      +"foo#{bar}baz"
    RUBY
  end

  it 'registers an offense and corrects for `String.new`' do
    expect_offense(<<~RUBY)
      String.new
      ^^^^^^^^^^ Use unary plus to get an unfrozen string literal.
    RUBY

    expect_correction(<<~RUBY)
      +''
    RUBY
  end

  it 'registers an offense and corrects for `String.new` with an empty string' do
    expect_offense(<<~RUBY)
      String.new('')
      ^^^^^^^^^^^^^^ Use unary plus to get an unfrozen string literal.
    RUBY

    expect_correction(<<~RUBY)
      +''
    RUBY
  end

  it 'registers an offense and corrects for `String.new` with a string' do
    expect_offense(<<~RUBY)
      String.new('foo')
      ^^^^^^^^^^^^^^^^^ Use unary plus to get an unfrozen string literal.
    RUBY

    expect_correction(<<~RUBY)
      +'foo'
    RUBY
  end

  it 'registers an offense and corrects when invoking a method after `String.new` with a string' do
    expect_offense(<<~RUBY)
      String.new('foo').force_encoding(Encoding::ASCII)
      ^^^^^^^^^^^^^^^^^ Use unary plus to get an unfrozen string literal.
    RUBY

    expect_correction(<<~RUBY)
      (+'foo').force_encoding(Encoding::ASCII)
    RUBY
  end

  it 'accepts an empty string with unary plus operator' do
    expect_no_offenses(<<~RUBY)
      +""
    RUBY
  end

  it 'accepts a string with unary plus operator' do
    expect_no_offenses(<<~RUBY)
      +"foobar"
    RUBY
  end

  it 'accepts `String.new` with capacity option' do
    expect_no_offenses(<<~RUBY)
      String.new(capacity: 100)
    RUBY
  end
end