Add tests for nested path expressions (@Arg.nested)

Author: johanrd

tests/lib/rules/template-no-capital-arguments.js

@@ -42,6 +42,18 @@ ruleTester.run('template-no-capital-arguments', rule, {
         }
       `,
     },
+    // Nested lowercase path is valid
+    {
+      filename: 'my-component.gjs',
+      code: `
+        import Component from '@glimmer/component';
+        export default class MyComponent extends Component {
+          <template>
+            <div>{{@arg.nested}}</div>
+          </template>
+        }
+      `,
+    },
   ],
 
   invalid: [
@@ -83,6 +95,19 @@ ruleTester.run('template-no-capital-arguments', rule, {
       `,
       errors: [{ messageId: 'noCapitalArguments' }],
     },
+    // Nested capital path
+    {
+      filename: 'my-component.gjs',
+      code: `
+        import Component from '@glimmer/component';
+        export default class MyComponent extends Component {
+          <template>
+            <div>{{@Arg.nested}}</div>
+          </template>
+        }
+      `,
+      errors: [{ messageId: 'noCapitalArguments' }],
+    },
     // Underscore prefix
     {
       filename: 'my-component.gjs',