test(@nestjs/common) cover multer, FileInterceptor unit tests

Author: kamilmysliwiec

src/common/test/interceptors/file.interceptor.spec.ts

@@ -26,5 +26,17 @@ describe('FileInterceptor', () => {
       expect(singleSpy.called).to.be.true;
       expect(singleSpy.calledWith(fieldName)).to.be.true;
     });
+    it('should transform exception', async () => {
+      const fieldName = 'file';
+      const target = new (FileInterceptor(fieldName));
+      const err = {};
+      const callback = (req, res, next) => next(err);
+
+      (target as any).upload = {
+        single: () => callback,
+      };
+      const req = {};
+      expect(target.intercept(req, null, stream$)).to.eventually.throw();
+    });
   });
 });

src/common/test/interceptors/multer/multer.utils.spec.ts

@@ -0,0 +1,43 @@
+import * as sinon from 'sinon';
+import { expect } from 'chai';
+import { transformException } from './../../../interceptors/multer/multer.utils';
+import { HttpException } from '../../../../../lib/common/exceptions/http.exception';
+import { multerExceptions } from '../../../interceptors/multer/multer.constants';
+import { PayloadTooLargeException, BadRequestException } from '../../../exceptions';
+
+describe('transformException', () => {
+  describe('if error does not exist', () => {
+    it('behave as identity', () => {
+      const err = undefined;
+      expect(
+        transformException(err)
+      ).to.be.eq(err);
+    });
+  });
+  describe('if error is instance of HttpException', () => {
+    it('behave as identity', () => {
+      const err = new HttpException('response', 500);
+      expect(
+        transformException(err)
+      ).to.be.eq(err);
+    });
+  });
+  describe('if error exists and is not instance of HttpException', () => {
+    describe('and is LIMIT_FILE_SIZE exception', () => {
+      it('should return "PayloadTooLargeException"', () => {
+        const err = { message: multerExceptions.LIMIT_FILE_SIZE };
+        expect(
+          transformException(err as any)
+        ).to.be.instanceof(PayloadTooLargeException);
+      });
+    });
+    describe('and is multer exception but not a LIMIT_FILE_SIZE', () => {
+      it('should return "BadRequestException"', () => {
+        const err = { message: multerExceptions.LIMIT_FIELD_KEY };
+        expect(
+          transformException(err as any)
+        ).to.be.instanceof(BadRequestException);
+      });
+    });
+  });
+});