chore(TypeScript): fix unit tests and coverage

test/unit/util/error.ts

@@ -47,7 +47,8 @@ describe('error', function () {
     it('should contain stack in err.stack', async function () {
       const err = await expect(engine.parseAndRender('{% . a %}')).be.rejected
       expect(err.message).to.contain('illegal tag syntax')
-      expect(err.stack).to.contain('at Object.parse')
+      console.log(err.stack)
+      expect(err.stack).to.contain('at Liquid.parse')
     })
     describe('captureStackTrace compatibility', function () {
       const captureStackTrace = Error.captureStackTrace

test/unit/util/promise.ts

@@ -52,9 +52,9 @@ describe('util/promise', function () {
         .then(() => expect(spy).to.not.have.been.called)
     })
   })
-  describe('.mapSeries()', function () {
+  describe('.mapSeries()', async function () {
     it('should resolve when all resolved', async function () {
-      const result = P.mapSeries(
+      const result = await P.mapSeries(
         ['first', 'second', 'third'],
         item => Promise.resolve(item)
       )