CSS: Ensure camel- vs kebab-cased names are not collapsed for CSS vars

Closes gh-4062

diff --git a/test/unit/css.js b/test/unit/css.js
index 29fa70906788f26aa7e1f8b53f1ce4f2a3fe0899..fbb42c301173c527864381f3427acdaeaf04907e 100644 (file)
--- a/test/unit/css.js
+++ b/test/unit/css.js
@@ -1632,10 +1632,12 @@ QUnit.test( "Do not throw on frame elements from css method (#15098)", function(
                assert.equal( div.css( "--color" ), "red", "Modified CSS custom property using object" );
 
                div.css( { "--mixedCase": "green" } );
+               div.css( { "--mixed-case": "red" } );
                assert.equal( div.css( "--mixedCase" ), "green",
                        "Modified CSS custom property with mixed case" );
 
                div.css( { "--theme-dark": "purple" } );
+               div.css( { "--themeDark": "red" } );
                assert.equal( div.css( "--theme-dark" ), "purple",
                        "Modified CSS custom property with dashed name" );