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

describe "Math.tan" do
  it "returns a float" do
    Math.tan(1.35).should be_kind_of(Float)
  end

  it "returns the tangent of the argument" do
    Math.tan(0.0).should == 0.0
    Math.tan(-0.0).should == -0.0
    Math.tan(4.22).should be_close(1.86406937682395, TOLERANCE)
    Math.tan(-9.65).should be_close(-0.229109052606441, TOLERANCE)
  end

  it "returns NaN if called with +-Infinitty" do
    Math.tan(infinity_value).nan?.should == true
    Math.tan(-infinity_value).nan?.should == true
  end

  it "raises a TypeError if the argument cannot be coerced with Float()" do
    lambda { Math.tan("test") }.should raise_error(TypeError)
  end

  it "returns NaN given NaN" do
    Math.tan(nan_value).nan?.should be_true
  end

  it "raises a TypeError if the argument is nil" do
    lambda { Math.tan(nil) }.should raise_error(TypeError)
  end

  it "accepts any argument that can be coerced with Float()" do
    Math.tan(MathSpecs::Float.new).should be_close(1.5574077246549, TOLERANCE)
  end
end

describe "Math#tan" do
  it "is accessible as a private instance method" do
    IncludesMath.new.send(:tan, 1.0).should be_close(1.5574077246549, TOLERANCE)
  end
end