test: add more case

Author: SwetaTanwar

lib/__tests/nested-selector-disambiguation.js

@@ -187,6 +187,63 @@ describe('Nested Selector Disambiguation', () => {
             const nestedContent = mainRule.block.children.head.data;
             assert.strictEqual(nestedContent.type, 'Rule', 'Should parse as nested rule, not declaration');
         });
+
+        it('should handle comma-separated selector list', () => {
+            const css = `main {
+                            p:first-of-type, span {
+                                margin-top: 0;
+                            }
+                        }`;
+            const ast = parse(css);
+
+            const mainRule = ast.children.head.data;
+            assert.strictEqual(mainRule.type, 'Rule', 'Should parse main rule');
+
+            const nestedContent = mainRule.block.children.head.data;
+            assert.strictEqual(nestedContent.type, 'Rule', 'Should parse as nested rule, not declaration');
+
+            // Verify the selector list structure
+            // The prelude IS the SelectorList
+            const selectorList = nestedContent.prelude;
+            assert.strictEqual(selectorList.type, 'SelectorList', 'Should have SelectorList');
+
+            // Collect all selectors in the list
+            const selectors = [];
+            let current = selectorList.children.head;
+            while (current) {
+                selectors.push(current.data);
+                current = current.next;
+            }
+
+            assert.strictEqual(selectors.length, 2, 'Should have 2 selectors in the list');
+
+            // Verify first selector: p:first-of-type
+            const firstSelectorChildren = [];
+            current = selectors[0].children.head;
+            while (current) {
+                firstSelectorChildren.push(current.data);
+                current = current.next;
+            }
+            assert.strictEqual(firstSelectorChildren[0].type, 'TypeSelector');
+            assert.strictEqual(firstSelectorChildren[0].name, 'p');
+            assert.strictEqual(firstSelectorChildren[1].type, 'PseudoClassSelector');
+            assert.strictEqual(firstSelectorChildren[1].name, 'first-of-type');
+
+            // Verify second selector: span
+            const secondSelectorChildren = [];
+            current = selectors[1].children.head;
+            while (current) {
+                secondSelectorChildren.push(current.data);
+                current = current.next;
+            }
+            assert.strictEqual(secondSelectorChildren[0].type, 'TypeSelector');
+            assert.strictEqual(secondSelectorChildren[0].name, 'span');
+
+            // Verify the nested declaration
+            const declaration = nestedContent.block.children.head.data;
+            assert.strictEqual(declaration.type, 'Declaration');
+            assert.strictEqual(declaration.property, 'margin-top');
+        });
     });
 
     describe('Regression tests for the original issue', () => {