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Diffstat (limited to 'spec/ruby/core/math/cos_spec.rb')
-rw-r--r-- | spec/ruby/core/math/cos_spec.rb | 42 |
1 files changed, 42 insertions, 0 deletions
diff --git a/spec/ruby/core/math/cos_spec.rb b/spec/ruby/core/math/cos_spec.rb new file mode 100644 index 0000000000..59b23b198b --- /dev/null +++ b/spec/ruby/core/math/cos_spec.rb @@ -0,0 +1,42 @@ +require File.expand_path('../../../spec_helper', __FILE__) +require File.expand_path('../fixtures/classes', __FILE__) + +# 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 |