Breaking a loop after resolving a promise

Question

I am writing a program to check the health endpoint of one of our APIs. So, before starting execution, I try to hit the health endpoint 5 times. If I get the desired response code during the 5 attempts, I break the loop and start test execution else give a message saying API is not healthy and stop the execution.

When below function is executed, it results in an error saying unsyntactic break Can someone suggest a better way to address this? I am using cypress.

  const maxRetry = Cypress.env('maxWarmUpRetries');
  const sleepTimeMs = 200;
  console.log(chalk.yellow('Checking API health before test execution...'));
  let healthCheckResponse;
  let healthStatusCode;
  for (let i = 0; i < maxRetry; i++) {
    console.log('Value of i is: ',i)
    apiHelper.requestHealth.then(response=>{
      healthCheckResponse=response;
      console.log('healthCheckStatusCode: ',healthCheckResponse.status)
      if (healthCheckResponse) {
        healthStatusCode = healthCheckResponse.status;
        if (healthStatusCode === 200) {
          console.log(chalk.green('API is healthy, moving forward with execution >>'));
          break;
        } else {
          console.log(chalk.yellow('Warm up - Checking API /health before test execution...'));
          if (i === maxRetry - 1) {
            console.log(chalk.red('Warm up - API /health is down!!! Suspending test execution.'));
            break;
          }
        }
      } else {
        console.log(chalk.yellow('Warm up - Checking API /health before test execution...'));
        if (i === maxRetry - 1) {
          console.log(chalk.red('Warm up - API /health is down!!! Suspending test execution.'));
          break;
        }
      }
    })
    
  }
});

Answer 1

For loops are problematic in Cypress because they run run faster than the Cypress command queue.

You don't show the Cypress commands above, but I assume they are following the warmup loop and are only called when healthStatusCode === 200.

You might find Test Retries will work better for you.

Individual Test(s)

If you want to configure retry attempts on a specific test, you can set this by using the test’s configuration.

There is good logging out of the box, so you could drop your additional logs.

const maxRetry = Cypress.env('maxWarmUpRetries');

it('allows user to login', {
  retries: { runMode: maxRetry, openMode: maxRetry }
}, () => {

  apiHelper.requestHealth.then(response=>{

    // force test retry by throwing an error
    if (!response || response.status !== 200) {
      throw new Error("test fails here")
    }

    // All good
    // run tests here

  })
})
})

Answer 2

Break should be inside a loop, you are calling break inside a callback function , this is why you are getting unsyntactic break

if you want to break from call back replace break with return but this won't break the outside for loop.

you should use await :

  for (let i = 0; i < maxRetry; i++) {
    console.log('Value of i is: ',i)
    healthCheckResponse= await apiHelper.requestHealth()
    healthStatusCode = healthCheckResponse.code 
          if (healthCheckResponse) {
        healthStatusCode = healthCheckResponse.status;
        if (healthStatusCode === 200) {
          console.log(chalk.green('API is healthy, moving forward with execution >>'));
          break;
        } else {
          console.log(chalk.yellow('Warm up - Checking API /health before test execution...'));
          if (i === maxRetry - 1) {
            console.log(chalk.red('Warm up - API /health is down!!! Suspending test execution.'));
            break;
          }
        }
      } else {
        console.log(chalk.yellow('Warm up - Checking API /health before test execution...'));
        if (i === maxRetry - 1) {
          console.log(chalk.red('Warm up - API /health is down!!! Suspending test execution.'));
          break;
        }
      }

Note: To use await the IT block or function inside which you are calloing this code should be declared as asyn

eg:

it('should edit a new item', async () => {
        for (let i = 0; i < maxRetry; i++) {
        console.log('Value of i is: ',i)
        healthCheckResponse= await apiHelper.requestHealth
        healthStatusCode = healthCheckResponse.code 
              if (healthCheckResponse) {
            healthStatusCode = healthCheckResponse.status;
            if (healthStatusCode === 200) {
              console.log(chalk.green('API is healthy, moving forward with execution >>'));
              break;
            } else {
              console.log(chalk.yellow('Warm up - Checking API /health before test execution...'));
              if (i === maxRetry - 1) {
                console.log(chalk.red('Warm up - API /health is down!!! Suspending test execution.'));
                break;
              }
            }
          } else {
            console.log(chalk.yellow('Warm up - Checking API /health before test execution...'));
            if (i === maxRetry - 1) {
              console.log(chalk.red('Warm up - API /health is down!!! Suspending test execution.'));
              break;
            }
          }
}

Answer 3

Well, here is how this was finally fixed. Using await was one step closer to the solution. However, it was cypress-promise that helped in fixing the issue. Click here to read more about cypress-promise. Now the code looks like this:

const sleepTimeMs = 500;
console.log(chalk.yellow('Checking API health before test execution...'));
let healthCheckResponse;
let healthStatusCode;
for (let i = 0; i < maxRetry; i++) {
  healthCheckResponse = await promisify(apiHelper.requestApiHealth());
  if (healthCheckResponse) {
    healthStatusCode = healthCheckResponse.status;
    if (healthStatusCode === 200) {
      console.log(chalk.green('API is healthy, moving forward with execution >>'));
      break;
    } else {
      console.log(chalk.yellow('Warm up - Checking API /health before test execution...'));
      if (i === maxRetry - 1) {
        console.log(chalk.red('Warm up - API /health is down!!! Suspending test execution.'));
        break;
      }
      cy.wait(sleepTimeMs);
    }
  } else {
    console.log(chalk.yellow('Warm up - Checking API /health before test execution...'));
    if (i === maxRetry - 1) {
      console.log(chalk.red('Warm up - API /health is down!!! Suspending test execution.'));
      break;
    }
    cy.wait(sleepTimeMs);
  }
}