1 files changed, 58 insertions, 0 deletions
diff --git a/spec/ruby/core/string/to_r_spec.rb b/spec/ruby/core/string/to_r_spec.rb
new file mode 100644
index 0000000000..7fa16f6f49
--- /dev/null
+++ b/spec/ruby/core/string/to_r_spec.rb
@@ -0,0 +1,58 @@
+require File.expand_path('../../../spec_helper', __FILE__)
+
+describe "String#to_r" do
+  it "returns a Rational object" do
+    String.new.to_r.should be_an_instance_of(Rational)
+  end
+
+  it "returns (0/1) for the empty String" do
+    "".to_r.should == Rational(0, 1)
+  end
+
+  it "returns (n/1) for a String starting with a decimal _n_" do
+    "2".to_r.should == Rational(2, 1)
+    "1765".to_r.should == Rational(1765, 1)
+  end
+
+  it "ignores trailing characters" do
+    "2 foo".to_r.should == Rational(2, 1)
+    "1765, ".to_r.should == Rational(1765, 1)
+  end
+
+  it "ignores leading spaces" do
+    " 2".to_r.should == Rational(2, 1)
+    "  1765, ".to_r.should == Rational(1765, 1)
+  end
+
+  it "does not ignore arbitrary, non-numeric leading characters" do
+    "The rational form of 33 is...".to_r.should_not == Rational(33, 1)
+    "a1765, ".to_r.should_not == Rational(1765, 1)
+  end
+
+  it "treats leading hypens as minus signs" do
+    "-20".to_r.should == Rational(-20, 1)
+  end
+
+  it "does not treat a leading period without a numeric prefix as a decimal point" do
+    ".9".to_r.should_not == Rational(8106479329266893, 9007199254740992)
+  end
+
+  it "understands decimal points" do
+    "3.33".to_r.should == Rational(333, 100)
+    "-3.33".to_r.should == Rational(-333, 100)
+  end
+
+  it "ignores underscores between numbers" do
+    "190_22".to_r.should == Rational(19022, 1)
+    "-190_22.7".to_r.should == Rational(-190227, 10)
+  end
+
+  it "understands a forward slash as separating the numerator from the denominator" do
+    "20/3".to_r.should == Rational(20, 3)
+    " -19.10/3".to_r.should == Rational(-191, 30)
+  end
+
+  it "returns (0/1) for Strings it can't parse" do
+    "glark".to_r.should == Rational(0,1)
+  end
+end