require_relative '../../spec_helper' require_relative 'fixtures/classes' # arctangent : (-Inf, Inf) --> (-PI/2, PI/2) describe "Math.atan" do it "returns a float" do Math.atan(1).should be_kind_of(Float) end it "returns the arctangent of the argument" do Math.atan(1).should be_close(Math::PI/4, TOLERANCE) Math.atan(0).should be_close(0.0, TOLERANCE) Math.atan(-1).should be_close(-Math::PI/4, TOLERANCE) Math.atan(0.25).should be_close(0.244978663126864, TOLERANCE) Math.atan(0.50).should be_close(0.463647609000806, TOLERANCE) Math.atan(0.75).should be_close(0.643501108793284, TOLERANCE) end it "raises a TypeError if the argument cannot be coerced with Float()" do -> { Math.atan("test") }.should raise_error(TypeError) end it "returns NaN given NaN" do Math.atan(nan_value).nan?.should be_true end it "raises a TypeError if the argument is nil" do -> { Math.atan(nil) }.should raise_error(TypeError) end it "accepts any argument that can be coerced with Float()" do Math.atan(MathSpecs::Float.new).should be_close(0.785398163397448, TOLERANCE) end end describe "Math#atan" do it "is accessible as a private instance method" do IncludesMath.new.send(:atan, 3.1415).should be_close(1.2626187313511, TOLERANCE) end end