83 lines
2.5 KiB
Ruby
83 lines
2.5 KiB
Ruby
# frozen_string_literal: true
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require 'fast_spec_helper'
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require_relative '../../../../rubocop/cop/performance/readlines_each'
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RSpec.describe RuboCop::Cop::Performance::ReadlinesEach do
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subject(:cop) { described_class.new }
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let(:message) { 'Avoid `IO.readlines.each`, since it reads contents into memory in full. Use `IO.each_line` or `IO.each` instead.' }
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shared_examples_for(:class_read) do |klass|
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context "and it is called as a class method on #{klass}" do
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it 'flags it as an offense' do
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leading_readline = "#{klass}.readlines(file_path)."
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padding = " " * leading_readline.length
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node = "#{leading_readline}each { |line| puts line }"
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expect_offense(<<~CODE, node: node)
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%{node}
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#{padding}^^^^ Avoid `IO.readlines.each`, since it reads contents into memory in full. [...]
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CODE
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end
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end
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context 'when just using readlines without each' do
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it 'does not flag it as an offense' do
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expect_no_offenses "contents = #{klass}.readlines(file_path)"
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end
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end
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end
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context 'when reading all lines using IO.readlines.each' do
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%w(IO File).each do |klass|
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it_behaves_like(:class_read, klass)
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end
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context 'and it is called as an instance method on a return value' do
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it 'flags it as an offense' do
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expect_offense <<~SOURCE
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get_file.readlines.each { |line| puts line }
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^^^^ #{message}
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SOURCE
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end
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end
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context 'and it is called as an instance method on an assigned variable' do
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it 'flags it as an offense' do
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expect_offense <<~SOURCE
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file = File.new(path)
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file.readlines.each { |line| puts line }
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^^^^ #{message}
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SOURCE
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end
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end
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context 'and it is called as an instance method on a new object' do
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it 'flags it as an offense' do
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expect_offense <<~SOURCE
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File.new(path).readlines.each { |line| puts line }
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^^^^ #{message}
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SOURCE
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end
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end
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it 'autocorrects `readlines.each` to `each_line`' do
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expect_offense(<<~CODE)
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obj.readlines.each { |line| line }
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^^^^ Avoid `IO.readlines.each`, since it reads contents into memory in full. [...]
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CODE
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expect_correction(<<~CODE)
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obj.each_line { |line| line }
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CODE
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end
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end
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context 'when just using readlines without each' do
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it 'does not flag it as an offense' do
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expect_no_offenses 'contents = my_file.readlines'
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end
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end
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end
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