1 files changed, 29 insertions, 0 deletions
diff --git a/spec/ruby/core/float/denominator_spec.rb b/spec/ruby/core/float/denominator_spec.rb
new file mode 100644
index 0000000000..85beaa98cd
--- /dev/null
+++ b/spec/ruby/core/float/denominator_spec.rb
@@ -0,0 +1,29 @@
+require_relative '../../spec_helper'
+
+describe "Float#denominator" do
+  before :each do
+    @numbers = [
+      0.0,
+      29871.22736282,
+      7772222663.0,
+      1.4592,
+    ].map {|n| [0-n, n]}.flatten
+  end
+
+  it "returns an Integer" do
+    @numbers.each do |number|
+      number.denominator.should.is_a?(Integer)
+    end
+  end
+
+  it "converts self to a Rational and returns the denominator" do
+    @numbers.each do |number|
+      number.denominator.should == Rational(number).denominator
+    end
+  end
+
+  it "returns 1 for NaN and Infinity" do
+    nan_value.denominator.should == 1
+    infinity_value.denominator.should == 1
+  end
+end