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

describe "Array#shift" do
  it "removes and returns the first element" do
    a = [5, 1, 1, 5, 4]
    a.shift.should == 5
    a.should == [1, 1, 5, 4]
    a.shift.should == 1
    a.should == [1, 5, 4]
    a.shift.should == 1
    a.should == [5, 4]
    a.shift.should == 5
    a.should == [4]
    a.shift.should == 4
    a.should == []
  end

  it "returns nil when the array is empty" do
    [].shift.should == nil
  end

  it "properly handles recursive arrays" do
    empty = ArraySpecs.empty_recursive_array
    empty.shift.should == []
    empty.should == []

    array = ArraySpecs.recursive_array
    array.shift.should == 1
    array[0..2].should == ['two', 3.0, array]
  end

  ruby_version_is "" ... "1.9" do
    it "raises a TypeError on a frozen array" do
      lambda { ArraySpecs.frozen_array.shift }.should raise_error(TypeError)
    end
    it "raises a TypeError on an empty frozen array" do
      lambda { ArraySpecs.empty_frozen_array.shift }.should raise_error(TypeError)
    end
  end

  ruby_version_is "1.9" do
    it "raises a RuntimeError on a frozen array" do
      lambda { ArraySpecs.frozen_array.shift }.should raise_error(RuntimeError)
    end
    it "raises a RuntimeError on an empty frozen array" do
      lambda { ArraySpecs.empty_frozen_array.shift }.should raise_error(RuntimeError)
    end
  end

  ruby_version_is '' ... '1.8.7' do
    it "raises an ArgumentError if passed an argument" do
      lambda{ [1, 2].shift(1) }.should raise_error(ArgumentError)
    end
  end

  describe "passed a number n as an argument" do
    ruby_version_is '1.8.7' do
      it "removes and returns an array with the first n element of the array" do
        a = [1, 2, 3, 4, 5, 6]

        a.shift(0).should == []
        a.should == [1, 2, 3, 4, 5, 6]

        a.shift(1).should == [1]
        a.should == [2, 3, 4, 5, 6]

        a.shift(2).should == [2, 3]
        a.should == [4, 5, 6]

        a.shift(3).should == [4, 5, 6]
        a.should == []
      end

      it "does not corrupt the array when shift without arguments is followed by shift with an argument" do
        a = [1, 2, 3, 4, 5]

        a.shift.should == 1
        a.shift(3).should == [2, 3, 4]
        a.should == [5]
      end

      it "returns a new empty array if there are no more elements" do
        a = []
        popped1 = a.shift(1)
        popped1.should == []
        a.should == []

        popped2 = a.shift(2)
        popped2.should == []
        a.should == []

        popped1.should_not equal(popped2)
      end

      it "returns whole elements if n exceeds size of the array" do
        a = [1, 2, 3, 4, 5]
        a.shift(6).should == [1, 2, 3, 4, 5]
        a.should == []
      end

      it "does not return self even when it returns whole elements" do
        a = [1, 2, 3, 4, 5]
        a.shift(5).should_not equal(a)

        a = [1, 2, 3, 4, 5]
        a.shift(6).should_not equal(a)
      end

      it "raises an ArgumentError if n is negative" do
        lambda{ [1, 2, 3].shift(-1) }.should raise_error(ArgumentError)
      end

      it "tries to convert n to an Integer using #to_int" do
        a = [1, 2, 3, 4]
        a.shift(2.3).should == [1, 2]

        obj = mock('to_int')
        obj.should_receive(:to_int).and_return(2)
        a.should == [3, 4]
        a.shift(obj).should == [3, 4]
        a.should == []
      end

      it "raises a TypeError when the passed n can be coerced to Integer" do
        lambda{ [1, 2].shift("cat") }.should raise_error(TypeError)
        lambda{ [1, 2].shift(nil) }.should raise_error(TypeError)
      end

      it "raises an ArgumentError if more arguments are passed" do
        lambda{ [1, 2].shift(1, 2) }.should raise_error(ArgumentError)
      end

      it "does not return subclass instances with Array subclass" do
        ArraySpecs::MyArray[1, 2, 3].shift(2).should be_an_instance_of(Array)
      end

      it "returns an untainted array even if the array is tainted" do
        ary = [1, 2].taint
        ary.shift(2).tainted?.should be_false
        ary.shift(0).tainted?.should be_false
      end

      it "keeps taint status" do
        a = [1, 2].taint
        a.shift(2)
        a.tainted?.should be_true
        a.shift(2)
        a.tainted?.should be_true
      end

      ruby_version_is '' ... '1.9' do
        it "raises a TypeError on a frozen array" do
          lambda { ArraySpecs.frozen_array.shift(2) }.should raise_error(TypeError)
          lambda { ArraySpecs.frozen_array.shift(0) }.should raise_error(TypeError)
        end
      end
    end
  end
end