1 files changed, 79 insertions, 0 deletions
diff --git a/spec/ruby/core/array/shared/union.rb b/spec/ruby/core/array/shared/union.rb
new file mode 100644
index 0000000000..0b60df9ca4
--- /dev/null
+++ b/spec/ruby/core/array/shared/union.rb
@@ -0,0 +1,79 @@
+describe :array_binary_union, shared: true do
+  it "returns an array of elements that appear in either array (union)" do
+    [].send(@method, []).should == []
+    [1, 2].send(@method, []).should == [1, 2]
+    [].send(@method, [1, 2]).should == [1, 2]
+    [ 1, 2, 3, 4 ].send(@method, [ 3, 4, 5 ]).should == [1, 2, 3, 4, 5]
+  end
+
+  it "creates an array with no duplicates" do
+    [ 1, 2, 3, 1, 4, 5 ].send(@method, [ 1, 3, 4, 5, 3, 6 ]).should == [1, 2, 3, 4, 5, 6]
+  end
+
+  it "creates an array with elements in order they are first encountered" do
+    [ 1, 2, 3, 1 ].send(@method, [ 1, 3, 4, 5 ]).should == [1, 2, 3, 4, 5]
+  end
+
+  it "properly handles recursive arrays" do
+    empty = ArraySpecs.empty_recursive_array
+    empty.send(@method, empty).should == empty
+
+    array = ArraySpecs.recursive_array
+    array.send(@method, []).should == [1, 'two', 3.0, array]
+    [].send(@method, array).should == [1, 'two', 3.0, array]
+    array.send(@method, array).should == [1, 'two', 3.0, array]
+    array.send(@method, empty).should == [1, 'two', 3.0, array, empty]
+  end
+
+  it "tries to convert the passed argument to an Array using #to_ary" do
+    obj = mock('[1,2,3]')
+    obj.should_receive(:to_ary).and_return([1, 2, 3])
+    [0].send(@method, obj).should == ([0] | [1, 2, 3])
+  end
+
+  # MRI follows hashing semantics here, so doesn't actually call eql?/hash for Integer/Symbol
+  it "acts as if using an intermediate hash to collect values" do
+    not_supported_on :opal do
+      [5.0, 4.0].send(@method, [5, 4]).should == [5.0, 4.0, 5, 4]
+    end
+
+    str = "x"
+    [str].send(@method, [str.dup]).should == [str]
+
+    obj1 = mock('1')
+    obj2 = mock('2')
+    obj1.stub!(:hash).and_return(0)
+    obj2.stub!(:hash).and_return(0)
+    obj2.should_receive(:eql?).at_least(1).and_return(true)
+
+    [obj1].send(@method, [obj2]).should == [obj1]
+    [obj1, obj1, obj2, obj2].send(@method, [obj2]).should == [obj1]
+
+    obj1 = mock('3')
+    obj2 = mock('4')
+    obj1.stub!(:hash).and_return(0)
+    obj2.stub!(:hash).and_return(0)
+    obj2.should_receive(:eql?).at_least(1).and_return(false)
+
+    [obj1].send(@method, [obj2]).should == [obj1, obj2]
+    [obj1, obj1, obj2, obj2].send(@method, [obj2]).should == [obj1, obj2]
+  end
+
+  it "does not return subclass instances for Array subclasses" do
+    ArraySpecs::MyArray[1, 2, 3].send(@method, []).should be_an_instance_of(Array)
+    ArraySpecs::MyArray[1, 2, 3].send(@method, ArraySpecs::MyArray[1, 2, 3]).should be_an_instance_of(Array)
+    [].send(@method, ArraySpecs::MyArray[1, 2, 3]).should be_an_instance_of(Array)
+  end
+
+  it "does not call to_ary on array subclasses" do
+    [1, 2].send(@method, ArraySpecs::ToAryArray[5, 6]).should == [1, 2, 5, 6]
+  end
+
+  it "properly handles an identical item even when its #eql? isn't reflexive" do
+    x = mock('x')
+    x.stub!(:hash).and_return(42)
+    x.stub!(:eql?).and_return(false) # Stubbed for clarity and latitude in implementation; not actually sent by MRI.
+
+    [x].send(@method, [x]).should == [x]
+  end
+end