1 files changed, 18 insertions, 0 deletions
diff --git a/spec/ruby/core/array/shared/unshift.rb b/spec/ruby/core/array/shared/unshift.rb
index fc82e19e2a..4941e098f6 100644
--- a/spec/ruby/core/array/shared/unshift.rb
+++ b/spec/ruby/core/array/shared/unshift.rb
@@ -22,6 +22,11 @@ describe :array_unshift, shared: true do
     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
@@ -43,4 +48,17 @@ describe :array_unshift, shared: true do
   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/oracle/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