Prepare all test setup requirement, then define the main test scenario and it's children with using describe and it.

logger.mocha.js

// Located inside __tests__ folder

require('dotenv').config()

// Call the mocked modules
const {
  loggerModule: logger
} = require('./mocks/logger.mockedModules')

// Act as the assertion library
const chai = require('chai')

// For test setup (spies, mock, stub)
const sinon = require('sinon')

// Sinon lib assertion in Chai
const sinonChai = require('sinon-chai')

// To match array / object
const deepEqualInAnyOrder = require('deep-equal-in-any-order')

// Define method expect from Chai library
const { expect } = chai

// Optional - Define multiple test cases using each
const forEach = require('mocha-each')

// For controller scope
// Define method `mockReq` (mocking the request) & `mockRes` (mocking the response)
const { mockReq, mockRes } = require('sinon-express-mock')

// Implementing sinonChai & deepEqualInAnyOrder into Chai library
chai.use(sinonChai)
chai.use(deepEqualInAnyOrder)

// Describe the name of the file
// Expected format -> `{file name [Controller/Model/Helper]} [Controller/Model/Helper] test`
describe('Logger Controller test', function() {
  // Describe the method you want to test
  // Expected format -> `{method name} test`
  describe('Create test', function() {
    // Inside this tested method, define the general cases with describe
    // In this case, there are two main cases (validation failed & passed)
    describe('Joi validation failed', function() {
      // Define several test cases using it
      // For better writing in specs, we can use forEach
      forEach([
        [
          'not sending logType attr in request params',
          { body: {} },
          `"logType" is required`
        ],
        [
          'not sending message attr in request params',
          { body: { logType: 'info' } },
          `"message" is required`
        ],
        [
          'sending invalid logType attr in request params',
          { body: { logType: 'aaaa' } },
          `"logType" must be one of [info, error, warning]`
        ]
      ]).it('throws error if `%s`', async (_, params, msg) => {
        // Remember the concept of AAA
        
        // Arrange
        let req = mockReq(params)
        let res = mockRes()
        let next = sinon.stub()
  
        // Act
        await logger.Create(req, res, next)
        
        // Assert
        expect(next.lastCall.args[0].details[0].message).eql(msg)
      })
    })
    
    describe('Joi validation passed', function() {
      // CODE
    })
  })
})