Testing Guide

Fundamentals of Tests

Writing tests are an essential part of any piece of code. Tests can be found in backend/test.

The difference between backend/tst.js and backend/test/*.test.js

tst.js is used as a scratch pad for testing classes. Use this in development to make sure your classes work as intended. This file is a normal js file can be run explicitly by typing node tst in the backend folder. In this file there is no notion of passing or failing. You can at all times delete any code in tst (leave the imports).

Running the test suite

cd backend cd to the backend.

npm run test run the test script.

Writing a test

each step outlined below is explained below the procedure below

1. Create a new file yourtestname.test.js.
2. Import the request verbs functions (Post, Delete, Get, Put)
3. Use one method and pass it the correct parameters (check signatures below)
4. All methods have a handler with parameter {expect, res}. The body of this handler is run and contains the tests for that request.
5. Within the body of the handler use the expect function to assert facts about the response object res.
6. You can expect a status in the response to be 0 (Ok) or expect that status to be 1 (Error), the test passes if the assertion is held true.

Import Post, Delete, Get

const {Post, Delete, Get} = require('../CreateTest')

Signatures

Get(APIroute:str ,description:str, handler:function)

Post(APIroute:str ,description:str data:json, handler:function)

Delete(APIroute:str ,description:str data:json, handler:function)

Note: The handler function is invoked once the backend returns a response (it's async).

Handler

res contains the response json data, expect is a function defined by the CreateTest module. Your actual tests are written within the handler body. ({expect, res})=> { // handler body }

Expect Function

These expect function calls occur with the hander body. These are the assertions made by your test. Examine the following examples of valid expect calls

eg1. expect(res.body.status).to.equal(1) test passes if status indicates error

eg2. expect(res.body.message).to.equal('Ok') test passes if message is equal to Ok

eg3. expect(true).to.equal(!false) test always passes

Example Code

Post('/login', 'message should say Welcome', {email: 'ced@gmail.com', password: 'ced'},({expect, res})=>{ 
      expect(res.body.message).to.equal('Welcome') // here the test will pass iff the message is Welcome
 })

Nested Requests

Nested Requests are possible and valuable for testing through the CRUD process.

1. Start by creating the record (Post), the response should contain some sort of id for the record.
2. Use that id to get the record (Get)
3. Update the record (Put)
4. Finally delete that record (Delete).

This will create an idempotent test, allowing it to be run again and again without changing the state of the database.

mockUser = { ... } 
Post('/createnewuser','Create User', mockUser,({expect, res})=>{
    expect(res.body.status).to.equal(0); // we expect to have no errors, ie status = 0
    expect(res.body.message).to.equal('Ok'); // we expect message to be Ok
    let insertId = res.body.user_id; // user_id is sent back in the response
    
    mockUser.firstName = "Jon"; // change names
    Put('updateuser', 'User should be updated', mockUser, (({expect, res})=>{
        expect(res.body.message).to.equal('User Updated.');
        expect(res.body.status).to.equal(0);
    })

    Delete('/deleteuser', 'User should be deleted.', {"user_id":insertId}, ({expect, res})=>{
        expect(res.body.message).to.equal('User Deleted.');
        expect(res.body.status).to.equal(0);
    })
})

Click here to see example of Nested Requests: lines 21 - 41