1 files changed, 85 insertions, 0 deletions
diff --git a/spec/ruby/core/array/shared/intersection.rb b/spec/ruby/core/array/shared/intersection.rb
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+++ b/spec/ruby/core/array/shared/intersection.rb
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+describe :array_intersection, shared: true do
+  it "creates an array with elements common to both arrays (intersection)" do
+    [].send(@method, []).should == []
+    [1, 2].send(@method, []).should == []
+    [].send(@method, [1, 2]).should == []
+    [ 1, 3, 5 ].send(@method, [ 1, 2, 3 ]).should == [1, 3]
+  end
+
+  it "creates an array with no duplicates" do
+    [ 1, 1, 3, 5 ].send(@method, [ 1, 2, 3 ]).uniq!.should == nil
+  end
+
+  it "creates an array with elements in order they are first encountered" do
+    [ 1, 2, 3, 2, 5, 6, 7, 8 ].send(@method, [ 5, 2, 3, 4 ]).should == [2, 3, 5] # array > other
+    [ 5, 2, 3, 4 ].send(@method, [ 1, 2, 3, 2, 5, 6, 7, 8 ]).should == [5, 2, 3] # array < other
+  end
+
+  it "does not modify the original Array" do
+    a = [1, 1, 3, 5]
+    a.send(@method, [1, 2, 3]).should == [1, 3]
+    a.should == [1, 1, 3, 5]
+  end
+
+  it "properly handles recursive arrays" do
+    empty = ArraySpecs.empty_recursive_array
+    empty.send(@method, empty).should == empty
+
+    ArraySpecs.recursive_array.send(@method, []).should == []
+    [].send(@method, ArraySpecs.recursive_array).should == []
+
+    ArraySpecs.recursive_array.send(@method, ArraySpecs.recursive_array).should == [1, 'two', 3.0, ArraySpecs.recursive_array]
+  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])
+    [1, 2].send(@method, obj).should == ([1, 2])
+  end
+
+  it "determines equivalence between elements in the sense of eql?" do
+    not_supported_on :opal do
+      [5.0, 4.0].send(@method, [5, 4]).should == []
+    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)
+    obj1.should_receive(:eql?).at_least(1).and_return(true)
+    obj2.stub!(:eql?).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)
+    obj1.should_receive(:eql?).at_least(1).and_return(false)
+
+    [obj1].send(@method, [obj2]).should == []
+    [obj1, obj1, obj2, obj2].send(@method, [obj2]).should == [obj2]
+  end
+
+  it "does 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
+    [5, 6].send(@method, ArraySpecs::ToAryArray[1, 2, 5, 6]).should == [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