1 files changed, 22 insertions, 4 deletions
diff --git a/spec/ruby/core/array/shared/unshift.rb b/spec/ruby/core/array/shared/unshift.rb
index fc82e19e2a..b636347cd3 100644
--- a/spec/ruby/core/array/shared/unshift.rb
+++ b/spec/ruby/core/array/shared/unshift.rb
@@ -1,9 +1,9 @@
 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.send(@method, "a").should.equal?(a)
     a.should == ['a', 1, 2, 3]
-    a.send(@method).should equal(a)
+    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]
@@ -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
@@ -36,11 +41,24 @@ describe :array_unshift, shared: true do
   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)
+    -> { ArraySpecs.frozen_array.send(@method, 1) }.should.raise(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)
+    -> { ArraySpecs.frozen_array.send(@method) }.should.raise(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