require File.expand_path('../../../spec_helper', __FILE__) require File.expand_path('../fixtures/classes', __FILE__) describe "Math.tanh" do it "returns a float" do Math.tanh(0.5).should be_kind_of(Float) end it "returns the hyperbolic tangent of the argument" do Math.tanh(0.0).should == 0.0 Math.tanh(-0.0).should == -0.0 Math.tanh(infinity_value).should == 1.0 Math.tanh(-infinity_value).should == -1.0 Math.tanh(2.5).should be_close(0.98661429815143, TOLERANCE) Math.tanh(-4.892).should be_close(-0.999887314427707, TOLERANCE) end it "raises a TypeError if the argument cannot be coerced with Float()" do lambda { Math.tanh("test") }.should raise_error(TypeError) end it "returns NaN given NaN" do Math.tanh(nan_value).nan?.should be_true end it "raises a TypeError if the argument is nil" do lambda { Math.tanh(nil) }.should raise_error(TypeError) end it "accepts any argument that can be coerced with Float()" do Math.tanh(MathSpecs::Float.new).should be_close(0.761594155955765, TOLERANCE) end end describe "Math#tanh" do it "is accessible as a private instance method" do IncludesMath.new.send(:tanh, 5.21).should be_close(0.99994034202065, TOLERANCE) end end