ruby--ruby/spec/ruby/core/hash/fetch_spec.rb

require File.expand_path('../../../spec_helper', __FILE__)
require File.expand_path('../fixtures/classes', __FILE__)

describe "Hash#fetch" do
  it "returns the value for key" do
    { a: 1, b: -1 }.fetch(:b).should == -1
  end

  it "raises a KeyError if key is not found" do
    lambda { {}.fetch(:a)       }.should raise_error(KeyError)
    lambda { Hash.new(5).fetch(:a)    }.should raise_error(KeyError)
    lambda { Hash.new { 5 }.fetch(:a) }.should raise_error(KeyError)
  end

  it "returns default if key is not found when passed a default" do
    {}.fetch(:a, nil).should == nil
    {}.fetch(:a, 'not here!').should == "not here!"
    { a: nil }.fetch(:a, 'not here!').should == nil
  end

  it "returns value of block if key is not found when passed a block" do
    {}.fetch('a') { |k| k + '!' }.should == "a!"
  end

  it "gives precedence to the default block over the default argument when passed both" do
    lambda {
      @result = {}.fetch(9, :foo) { |i| i * i }
    }.should complain(/block supersedes default value argument/)
    @result.should == 81
  end

  it "raises an ArgumentError when not passed one or two arguments" do
    lambda { {}.fetch()        }.should raise_error(ArgumentError)
    lambda { {}.fetch(1, 2, 3) }.should raise_error(ArgumentError)
  end
end