1 files changed, 39 insertions, 0 deletions
diff --git a/spec/ruby/core/math/tanh_spec.rb b/spec/ruby/core/math/tanh_spec.rb
new file mode 100644
index 0000000000..74a938ffd8
--- /dev/null
+++ b/spec/ruby/core/math/tanh_spec.rb
@@ -0,0 +1,39 @@
+require_relative '../../spec_helper'
+require_relative 'fixtures/classes'
+
+describe "Math.tanh" do
+  it "returns a float" do
+    Math.tanh(0.5).should.is_a?(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
+    -> { Math.tanh("test") }.should.raise(TypeError)
+  end
+
+  it "returns NaN given NaN" do
+    Math.tanh(nan_value).nan?.should == true
+  end
+
+  it "raises a TypeError if the argument is nil" do
+    -> { Math.tanh(nil) }.should.raise(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