require_relative '../../spec_helper' require_relative 'fixtures/classes' # cosine : (-Inf, Inf) --> (-1.0, 1.0) describe "Math.cos" do it "returns a float" do Math.cos(Math::PI).should be_kind_of(Float) end it "returns the cosine of the argument expressed in radians" do Math.cos(Math::PI).should be_close(-1.0, TOLERANCE) Math.cos(0).should be_close(1.0, TOLERANCE) Math.cos(Math::PI/2).should be_close(0.0, TOLERANCE) Math.cos(3*Math::PI/2).should be_close(0.0, TOLERANCE) Math.cos(2*Math::PI).should be_close(1.0, TOLERANCE) end it "raises a TypeError unless the argument is Numeric and has #to_f" do lambda { Math.cos("test") }.should raise_error(TypeError) end it "returns NaN given NaN" do Math.cos(nan_value).nan?.should be_true end it "raises a TypeError if the argument is nil" do lambda { Math.cos(nil) }.should raise_error(TypeError) end it "coerces its argument with #to_f" do f = mock_numeric('8.2') f.should_receive(:to_f).and_return(8.2) Math.cos(f).should == Math.cos(8.2) end end describe "Math#cos" do it "is accessible as a private instance method" do IncludesMath.new.send(:cos, 3.1415).should be_close(-0.999999995707656, TOLERANCE) end end