1 files changed, 41 insertions, 0 deletions
diff --git a/spec/ruby/core/complex/to_f_spec.rb b/spec/ruby/core/complex/to_f_spec.rb
new file mode 100644
index 0000000000..9f3265cdb9
--- /dev/null
+++ b/spec/ruby/core/complex/to_f_spec.rb
@@ -0,0 +1,41 @@
+require_relative '../../spec_helper'
+
+describe "Complex#to_f" do
+  describe "when the imaginary part is Integer 0" do
+    it "returns the result of sending #to_f to the real part" do
+      real = mock_numeric('real')
+      real.should_receive(:to_f).and_return(:f)
+      Complex(real, 0).to_f.should == :f
+    end
+  end
+
+  describe "when the imaginary part is Rational 0" do
+    it "returns the result of sending #to_f to the real part" do
+      real = mock_numeric('real')
+      real.should_receive(:to_f).and_return(:f)
+      Complex(real, Rational(0)).to_f.should == :f
+    end
+  end
+
+  describe "when the imaginary part responds to #== 0 with true" do
+    it "returns the result of sending #to_f to the real part" do
+      real = mock_numeric('real')
+      real.should_receive(:to_f).and_return(:f)
+      imag = mock_numeric('imag')
+      imag.should_receive(:==).with(0).any_number_of_times.and_return(true)
+      Complex(real, imag).to_f.should == :f
+    end
+  end
+
+  describe "when the imaginary part is non-zero" do
+    it "raises RangeError" do
+      -> { Complex(0, 1).to_f }.should.raise(RangeError)
+    end
+  end
+
+  describe "when the imaginary part is Float 0.0" do
+    it "raises RangeError" do
+      -> { Complex(0, 0.0).to_f }.should.raise(RangeError)
+    end
+  end
+end