add test coverage for #83

src/collections/cursor.ts

@@ -35,8 +35,8 @@ export class FindCursor {
         this.options = options ?? {};
 
         const isOverPageSizeLimit = this.options.sort &&
-      this.options.sort.$vector == null &&
-      (this.options.limit == null || this.options.limit > 20);
+            this.options.sort.$vector == null &&
+            (this.options.limit == null || this.options.limit > 20);
         if (isOverPageSizeLimit) {
             throw new Error('Cannot set sort option without limit <= 20, JSON API can currently only return 20 documents with sort');
         }

tests/collections/cursor.test.ts

@@ -183,6 +183,24 @@ describe(`StargateMongoose - ${testClient} Connection - collections.cursor`, asy
             });
             assert.strictEqual(docCount, sampleUsers.length);
         });
+        it('should only store at most `pageSize` documents at a time', async () => {
+            const docs = [];
+            for (let i = 0; i < 35; ++i) {
+                docs.push({ name: `doc ${i}` });
+            }
+            while (docs.length > 0) {
+                const toInsert = docs.splice(0, 20);
+                await collection.insertMany(toInsert);
+            }
+
+            const cursor = new FindCursor(collection, {});
+            let docCount = 0;
+            await cursor.forEach(() => {
+                assert.equal(cursor.page.length, docCount < 20 ? 20 : 15);
+                docCount++;
+            });
+            assert.strictEqual(docCount, 35);
+        });
     });
 
     describe('Cursor noops', () => {