require_relative '../../spec_helper' describe :complex_multiply, shared: true do describe "with Complex" do it "multiplies according to the usual rule for complex numbers: (a + bi) * (c + di) = ac - bd + (ad + bc)i" do (Complex(1, 2) * Complex(10, 20)).should == Complex((1 * 10) - (2 * 20), (1 * 20) + (2 * 10)) (Complex(1.5, 2.1) * Complex(100.2, -30.3)).should == Complex((1.5 * 100.2) - (2.1 * -30.3), (1.5 * -30.3) + (2.1 * 100.2)) end end describe "with Integer" do it "multiplies both parts of self by the given Integer" do (Complex(3, 2) * 50).should == Complex(150, 100) (Complex(-3, 2) * 50.5).should == Complex(-151.5, 101) end end describe "with Object" do it "tries to coerce self into other" do value = Complex(3, 9) obj = mock("Object") obj.should_receive(:coerce).with(value).and_return([2, 5]) (value * obj).should == 2 * 5 end end describe "with a Numeric which responds to #real? with true" do it "multiples both parts of self by other" do other = mock_numeric('other') real = mock_numeric('real') imag = mock_numeric('imag') other.should_receive(:real?).and_return(true) real.should_receive(:*).with(other).and_return(1) imag.should_receive(:*).with(other).and_return(2) (Complex(real, imag) * other).should == Complex(1, 2) end describe "with a Numeric which responds to #real? with false" do it "coerces the passed argument to Complex and multiplies the resulting elements" do complex = Complex(3, 0) other = mock_numeric('other') other.should_receive(:real?).any_number_of_times.and_return(false) other.should_receive(:coerce).with(complex).and_return([5, 2]) (complex * other).should == 10 end end end end