add missing test

code coverage bug uncovered?

Author: yaacovCR

src/execution/__tests__/defer-test.ts

@@ -587,6 +587,56 @@ describe('Execute: defer directive', () => {
     ]);
   });
 
+  it('Separately emits defer fragments with different labels with varying subfields that return promises', async () => {
+    const document = parse(`
+      query HeroNameQuery {
+        ... @defer(label: "DeferID") {
+          hero {
+            id
+          }
+        }
+        ... @defer(label: "DeferName") {
+          hero {
+            name
+          }
+        }
+      }
+    `);
+    const result = await complete(document, {
+      hero: {
+        id: () => Promise.resolve('1'),
+        name: () => Promise.resolve('Luke'),
+      },
+    });
+    expectJSON(result).toDeepEqual([
+      {
+        data: {},
+        hasNext: true,
+      },
+      {
+        incremental: [
+          {
+            data: { hero: {} },
+            path: [],
+          },
+          {
+            data: { id: '1' },
+            path: ['hero'],
+          },
+          {
+            data: { name: 'Luke' },
+            path: ['hero'],
+          },
+        ],
+        completed: [
+          { path: [], label: 'DeferID' },
+          { path: [], label: 'DeferName' },
+        ],
+        hasNext: false,
+      },
+    ]);
+  });
+
   it('Separately emits defer fragments with varying subfields of same priorities but different level of defers', async () => {
     const document = parse(`
       query HeroNameQuery {