describe :start_with, shared: true do
  # the @method should either be :to_s or :to_sym

  it "returns true only if beginning match" do
    s = "hello".send(@method)
    s.should.start_with?('h')
    s.should.start_with?('hel')
    s.should_not.start_with?('el')
  end

  it "returns true only if any beginning match" do
    "hello".send(@method).should.start_with?('x', 'y', 'he', 'z')
  end

  it "returns true if the search string is empty" do
    "hello".send(@method).should.start_with?("")
    "".send(@method).should.start_with?("")
  end

  it "converts its argument using :to_str" do
    s = "hello".send(@method)
    find = mock('h')
    find.should_receive(:to_str).and_return("h")
    s.should.start_with?(find)
  end

  it "ignores arguments not convertible to string" do
    "hello".send(@method).should_not.start_with?()
    -> { "hello".send(@method).start_with?(1) }.should raise_error(TypeError)
    -> { "hello".send(@method).start_with?(["h"]) }.should raise_error(TypeError)
    -> { "hello".send(@method).start_with?(1, nil, "h") }.should raise_error(TypeError)
  end

  it "uses only the needed arguments" do
    find = mock('h')
    find.should_not_receive(:to_str)
    "hello".send(@method).should.start_with?("h",find)
  end

  it "works for multibyte strings" do
    "céréale".send(@method).should.start_with?("cér")
  end

  it "supports regexps" do
    regexp = /[h1]/
    "hello".send(@method).should.start_with?(regexp)
    "1337".send(@method).should.start_with?(regexp)
    "foxes are 1337".send(@method).should_not.start_with?(regexp)
    "chunky\n12bacon".send(@method).should_not.start_with?(/12/)
  end

  it "supports regexps with ^ and $ modifiers" do
    regexp1 = /^\d{2}/
    regexp2 = /\d{2}$/
    "12test".send(@method).should.start_with?(regexp1)
    "test12".send(@method).should_not.start_with?(regexp1)
    "12test".send(@method).should_not.start_with?(regexp2)
    "test12".send(@method).should_not.start_with?(regexp2)
  end

  it "sets Regexp.last_match if it returns true" do
    regexp = /test-(\d+)/
    "test-1337".send(@method).start_with?(regexp).should be_true
    Regexp.last_match.should_not be_nil
    Regexp.last_match[1].should == "1337"
    $1.should == "1337"

    "test-asdf".send(@method).start_with?(regexp).should be_false
    Regexp.last_match.should be_nil
    $1.should be_nil
  end
end
