Tests: add additional test for jQuery.isPlainObject

Ref 00575d4d8c7421c5119f181009374ff2e7736127
Also see discussion in
https://github.com/jquery/jquery/pull/2970#discussion_r54970557

1 files changed, 11 insertions, 1 deletions

diff --git a/test/unit/core.js b/test/unit/core.js
index d71539c02..2f4831828 100644
--- a/test/unit/core.js
+++ b/test/unit/core.js
@@ -365,7 +365,6 @@ QUnit.asyncTest( "isPlainObject", function( assert ) {
 	}
 } );
 
-//
 QUnit[ typeof Symbol === "function" ? "test" : "skip" ]( "isPlainObject(Symbol)", function( assert ) {
 	assert.expect( 2 );
 
@@ -373,6 +372,17 @@ QUnit[ typeof Symbol === "function" ? "test" : "skip" ]( "isPlainObject(Symbol)"
 	assert.equal( jQuery.isPlainObject( Object( Symbol() ) ), false, "Symbol inside an object" );
 } );
 
+QUnit[ "assign" in Object ? "test" : "skip" ]( "isPlainObject(Object.assign(...))",
+	function( assert ) {
+		assert.expect( 1 );
+
+		var parentObj = { foo: "bar" };
+		var childObj = Object.assign( Object.create( parentObj ), { bar: "foo" } );
+
+		assert.ok( !jQuery.isPlainObject( childObj ), "isPlainObject(Object.assign(...))" );
+	}
+);
+
 
 QUnit.test( "isFunction", function( assert ) {
 	assert.expect( 19 );