1 files changed, 33 insertions, 0 deletions
diff --git a/spec/ruby/core/numeric/numerator_spec.rb b/spec/ruby/core/numeric/numerator_spec.rb
new file mode 100644
index 0000000000..4a20f8792a
--- /dev/null
+++ b/spec/ruby/core/numeric/numerator_spec.rb
@@ -0,0 +1,33 @@
+require File.expand_path('../../../spec_helper', __FILE__)
+
+describe "Numeric#numerator" do
+  before :all do
+    @numbers = [
+      0,
+      29871,
+      99999999999999**99,
+      -72628191273,
+      29282.2827,
+      -2927.00091,
+      0.0,
+      12.0,
+      Float::MAX,
+    ]
+  end
+
+  # This isn't entirely true, as NaN.numerator works, whereas
+  # Rational(NaN) raises an exception, but we test this in Float#numerator
+  it "converts self to a Rational object then returns its numerator" do
+    @numbers.each do |number|
+      number.numerator.should == Rational(number).numerator
+    end
+  end
+
+  it "works with Numeric subclasses" do
+    rational = mock_numeric('rational')
+    rational.should_receive(:numerator).and_return(:numerator)
+    numeric = mock_numeric('numeric')
+    numeric.should_receive(:to_r).and_return(rational)
+    numeric.numerator.should == :numerator
+  end
+end