ruby--ruby/spec/ruby/library/stringscanner/exist_spec.rb

require_relative '../../spec_helper'
require 'strscan'

describe "StringScanner#exist?" do
  before :each do
    @s = StringScanner.new("This is a test")
  end

  it "returns the index of the first occurrence of the given pattern" do
    @s.exist?(/s/).should == 4
    @s.scan(/This is/)
    @s.exist?(/s/).should == 6
  end

  it "returns 0 if the pattern is empty" do
    @s.exist?(//).should == 0
  end

  it "returns nil if the pattern isn't found in the string" do
    @s.exist?(/S/).should == nil
    @s.scan(/This is/)
    @s.exist?(/i/).should == nil
  end

  it "raises TypeError if given a String" do
    -> {
      @s.exist?('T')
    }.should raise_error(TypeError, 'wrong argument type String (expected Regexp)')
  end
end