1 files changed, 20 insertions, 21 deletions
diff --git a/spec/ruby/core/array/plus_spec.rb b/spec/ruby/core/array/plus_spec.rb
index 7692163980..7ead927fc0 100644
--- a/spec/ruby/core/array/plus_spec.rb
+++ b/spec/ruby/core/array/plus_spec.rb
@@ -14,10 +14,23 @@ describe "Array#+" do
     (ary + ary).should == [1, 2, 3, 1, 2, 3]
   end
 
-  it "tries to convert the passed argument to an Array using #to_ary" do
-    obj = mock('["x", "y"]')
-    obj.should_receive(:to_ary).and_return(["x", "y"])
-    ([1, 2, 3] + obj).should == [1, 2, 3, "x", "y"]
+  describe "converts the passed argument to an Array using #to_ary" do
+    it "successfully concatenates the resulting array from the #to_ary call" do
+      obj = mock('["x", "y"]')
+      obj.should_receive(:to_ary).and_return(["x", "y"])
+      ([1, 2, 3] + obj).should == [1, 2, 3, "x", "y"]
+    end
+
+    it "raises a TypeError if the given argument can't be converted to an array" do
+      -> { [1, 2, 3] + nil }.should.raise(TypeError)
+      -> { [1, 2, 3] + "abc" }.should.raise(TypeError)
+    end
+
+    it "raises a NoMethodError if the given argument raises a NoMethodError during type coercion to an Array" do
+      obj = mock("hello")
+      obj.should_receive(:to_ary).and_raise(NoMethodError)
+      -> { [1, 2, 3] + obj }.should.raise(NoMethodError)
+    end
   end
 
   it "properly handles recursive arrays" do
@@ -32,26 +45,12 @@ describe "Array#+" do
   end
 
   it "does return subclass instances with Array subclasses" do
-    (ArraySpecs::MyArray[1, 2, 3] + []).should be_an_instance_of(Array)
-    (ArraySpecs::MyArray[1, 2, 3] + ArraySpecs::MyArray[]).should be_an_instance_of(Array)
-    ([1, 2, 3] + ArraySpecs::MyArray[]).should be_an_instance_of(Array)
+    (ArraySpecs::MyArray[1, 2, 3] + []).should.instance_of?(Array)
+    (ArraySpecs::MyArray[1, 2, 3] + ArraySpecs::MyArray[]).should.instance_of?(Array)
+    ([1, 2, 3] + ArraySpecs::MyArray[]).should.instance_of?(Array)
   end
 
   it "does not call to_ary on array subclasses" do
     ([5, 6] + ArraySpecs::ToAryArray[1, 2]).should == [5, 6, 1, 2]
   end
-
-  it "does not get infected even if an original array is tainted" do
-    ([1, 2] + [3, 4]).tainted?.should be_false
-    ([1, 2].taint + [3, 4]).tainted?.should be_false
-    ([1, 2] + [3, 4].taint).tainted?.should be_false
-    ([1, 2].taint + [3, 4].taint).tainted?.should be_false
-  end
-
-  it "does not infected even if an original array is untrusted" do
-    ([1, 2] + [3, 4]).untrusted?.should be_false
-    ([1, 2].untrust + [3, 4]).untrusted?.should be_false
-    ([1, 2] + [3, 4].untrust).untrusted?.should be_false
-    ([1, 2].untrust + [3, 4].untrust).untrusted?.should be_false
-  end
 end