tests(@nestjs/core) fix failing unit tests

packages/core/test/middleware/utils.spec.ts

@@ -0,0 +1,66 @@
+import * as sinon from 'sinon';
+import { expect } from 'chai';
+import {
+  filterMiddleware,
+  mapToClass,
+  isClass,
+  assignToken,
+} from '../../middleware/utils';
+
+describe('middleware utils', () => {
+  class Test {}
+  function fnMiddleware(req, res, next) {}
+
+  describe('filterMiddleware', () => {
+    let middleware: any[];
+    beforeEach(() => {
+      middleware = [Test, fnMiddleware, undefined, null];
+    });
+    it('should returns filtered middleware', () => {
+      expect(filterMiddleware(middleware)).to.have.length(2);
+    });
+  });
+  describe('mapToClass', () => {
+    describe('when middleware is a class', () => {
+      it('should returns identity', () => {
+        const type = mapToClass(Test);
+        expect(type).to.eql(Test);
+      });
+    });
+    describe('when middleware is a function', () => {
+      it('should returns metatype', () => {
+        const metatype = mapToClass(fnMiddleware);
+        expect(metatype).to.not.eql(fnMiddleware);
+      });
+      it('should define `resolve` method', () => {
+        const metatype = mapToClass(fnMiddleware);
+        expect(new metatype().resolve).to.exist;
+      });
+      it('should encapsulate function', () => {
+        const spy = sinon.spy();
+        const metatype = mapToClass(spy);
+        new metatype().resolve()();
+        expect(spy.called).to.be.true;
+      });
+    });
+  });
+  describe('isClass', () => {
+    describe('when middleware is a class', () => {
+      it('should returns true', () => {
+        expect(isClass(Test)).to.be.true;
+      });
+    });
+    describe('when middleware is a function', () => {
+      it('should returns false', () => {
+        expect(isClass(fnMiddleware)).to.be.false;
+      });
+    });
+  });
+  describe('assignToken', () => {
+    describe('should define `name` property on metatype', () => {
+      const anonymousType = class {};
+      assignToken(anonymousType);
+      expect(anonymousType.name).to.exist;
+    });
+  });
+});