1 files changed, 26 insertions, 0 deletions
diff --git a/spec/ruby/shared/rational/truncate.rb b/spec/ruby/shared/rational/truncate.rb
index 761dd3113a..df5198ca02 100644
--- a/spec/ruby/shared/rational/truncate.rb
+++ b/spec/ruby/shared/rational/truncate.rb
@@ -17,6 +17,18 @@ describe :rational_truncate, shared: true do
     end
   end
 
+  describe "with an explicit precision = 0" do
+    it "returns an integer" do
+      @rational.truncate(0).should be_kind_of(Integer)
+    end
+
+    it "returns the truncated value toward 0" do
+      @rational.truncate(0).should == 314
+      Rational(1, 2).truncate(0).should == 0
+      Rational(-1, 2).truncate(0).should == 0
+    end
+  end
+
   describe "with a precision < 0" do
     it "returns an integer" do
       @rational.truncate(-2).should be_kind_of(Integer)
@@ -42,4 +54,18 @@ describe :rational_truncate, shared: true do
       @rational.truncate(3).should == Rational(62857, 200)
     end
   end
+
+  describe "with an invalid value for precision" do
+    it "raises a TypeError" do
+      -> { @rational.truncate(nil) }.should raise_error(TypeError, "not an integer")
+      -> { @rational.truncate(1.0) }.should raise_error(TypeError, "not an integer")
+      -> { @rational.truncate('') }.should raise_error(TypeError, "not an integer")
+    end
+
+    it "does not call to_int on the argument" do
+      object = Object.new
+      object.should_not_receive(:to_int)
+      -> { @rational.truncate(object) }.should raise_error(TypeError, "not an integer")
+    end
+  end
 end