1 files changed, 56 insertions, 0 deletions
diff --git a/spec/ruby/core/array/plus_spec.rb b/spec/ruby/core/array/plus_spec.rb
new file mode 100644
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+++ b/spec/ruby/core/array/plus_spec.rb
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+require_relative '../../spec_helper'
+require_relative 'fixtures/classes'
+
+describe "Array#+" do
+  it "concatenates two arrays" do
+    ([ 1, 2, 3 ] + [ 3, 4, 5 ]).should == [1, 2, 3, 3, 4, 5]
+    ([ 1, 2, 3 ] + []).should == [1, 2, 3]
+    ([] + [ 1, 2, 3 ]).should == [1, 2, 3]
+    ([] + []).should == []
+  end
+
+  it "can concatenate an array with itself" do
+    ary = [1, 2, 3]
+    (ary + ary).should == [1, 2, 3, 1, 2, 3]
+  end
+
+  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_error(TypeError)
+      -> { [1, 2, 3] + "abc" }.should raise_error(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_error(NoMethodError)
+    end
+  end
+
+  it "properly handles recursive arrays" do
+    empty = ArraySpecs.empty_recursive_array
+    (empty + empty).should == [empty, empty]
+
+    array = ArraySpecs.recursive_array
+    (empty + array).should == [empty, 1, 'two', 3.0, array, array, array, array, array]
+    (array + array).should == [
+      1, 'two', 3.0, array, array, array, array, array,
+      1, 'two', 3.0, array, array, array, array, array]
+  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)
+  end
+
+  it "does not call to_ary on array subclasses" do
+    ([5, 6] + ArraySpecs::ToAryArray[1, 2]).should == [5, 6, 1, 2]
+  end
+end