Failing test for concatenated classes on contextual glimmer components

Author: cibernox

packages/@ember/-internals/glimmer/tests/integration/components/angle-bracket-invocation-test.js

@@ -783,6 +783,25 @@ if (EMBER_GLIMMER_ANGLE_BRACKET_INVOCATION) {
         });
       }
 
+      '@test merges class attribute with `...attributes` in yielded contextual component ("splattributes")'() {
+        this.registerComponent('foo-bar', {
+          ComponentClass: Component.extend({ tagName: '' }),
+          template: '{{yield (hash baz=(component "foo-bar/baz"))}}',
+        });
+        this.registerComponent('foo-bar/baz', {
+          ComponentClass: Component.extend({ tagName: '' }),
+          template: '<div class="default-class" ...attributes>hello</div>',
+        });
+
+        this.render('<FooBar as |fb|><fb.baz class="invocation-class"></fb.baz></FooBar>');
+
+        this.assertElement(this.firstChild, {
+          tagName: 'div',
+          attrs: { class: classes('default-class invocation-class') },
+          content: 'hello',
+        });
+      }
+
       '@test can include `...attributes` in multiple elements in tagless component ("splattributes")'() {
         this.registerComponent('foo-bar', {
           ComponentClass: Component.extend({ tagName: '' }),