Add migration tests.

Author: tom-andersen

packages/firestore/test/unit/local/indexeddb_persistence.test.ts

@@ -75,6 +75,9 @@ import {
   V12_STORES,
   V13_STORES,
   V14_STORES,
+  V15_STORES,
+  V16_STORES,
+  V17_STORES,
   V1_STORES,
   V3_STORES,
   V4_STORES,
@@ -1229,6 +1232,30 @@ describe('IndexedDbSchema: createOrUpgradeDb', () => {
     });
   });
 
+  it('can upgrade from version 14 to 15', async () => {
+    await withDb(14, async () => {});
+    await withDb(15, async (db, version, objectStores) => {
+      expect(version).to.have.equal(14);
+      expect(objectStores).to.have.members(V15_STORES);
+    });
+  });
+
+  it('can upgrade from version 15 to 16', async () => {
+    await withDb(15, async () => {});
+    await withDb(16, async (db, version, objectStores) => {
+      expect(version).to.have.equal(15);
+      expect(objectStores).to.have.members(V16_STORES);
+    });
+  });
+
+  it('can upgrade from version 16 to 17', async () => {
+    await withDb(16, async () => {});
+    await withDb(17, async (db, version, objectStores) => {
+      expect(version).to.have.equal(16);
+      expect(objectStores).to.have.members(V17_STORES);
+    });
+  });
+
   it('downgrading throws a custom error', async function (this: Context) {
     // Upgrade to latest version
     await withDb(SCHEMA_VERSION, async (db, version) => {