1 files changed, 64 insertions, 0 deletions
diff --git a/spec/ruby/core/array/shared/unshift.rb b/spec/ruby/core/array/shared/unshift.rb
new file mode 100644
index 0000000000..9e0fe7556a
--- /dev/null
+++ b/spec/ruby/core/array/shared/unshift.rb
@@ -0,0 +1,64 @@
+describe :array_unshift, shared: true do
+  it "prepends object to the original array" do
+    a = [1, 2, 3]
+    a.send(@method, "a").should equal(a)
+    a.should == ['a', 1, 2, 3]
+    a.send(@method).should equal(a)
+    a.should == ['a', 1, 2, 3]
+    a.send(@method, 5, 4, 3)
+    a.should == [5, 4, 3, 'a', 1, 2, 3]
+
+    # shift all but one element
+    a = [1, 2]
+    a.shift
+    a.send(@method, 3, 4)
+    a.should == [3, 4, 2]
+
+    # now shift all elements
+    a.shift
+    a.shift
+    a.shift
+    a.send(@method, 3, 4)
+    a.should == [3, 4]
+  end
+
+  it "returns self" do
+    a = [1, 2, 3]
+    a.send(@method, "a").should.equal?(a)
+  end
+
+  it "quietly ignores unshifting nothing" do
+    [].send(@method).should == []
+  end
+
+  it "properly handles recursive arrays" do
+    empty = ArraySpecs.empty_recursive_array
+    empty.send(@method, :new).should == [:new, empty]
+
+    array = ArraySpecs.recursive_array
+    array.send(@method, :new)
+    array[0..5].should == [:new, 1, 'two', 3.0, array, array]
+  end
+
+  it "raises a FrozenError on a frozen array when the array is modified" do
+    -> { ArraySpecs.frozen_array.send(@method, 1) }.should raise_error(FrozenError)
+  end
+
+  # see [ruby-core:23666]
+  it "raises a FrozenError on a frozen array when the array would not be modified" do
+    -> { ArraySpecs.frozen_array.send(@method) }.should raise_error(FrozenError)
+  end
+
+  # https://github.com/truffleruby/truffleruby/issues/2772
+  it "doesn't rely on Array#[]= so it can be overridden" do
+    subclass = Class.new(Array) do
+      def []=(*)
+        raise "[]= is called"
+      end
+    end
+
+    array = subclass.new
+    array.send(@method, 1)
+    array.should == [1]
+  end
+end