Js What Is A Test Lab

You understand how to read tests, now it's time to run the tests. We've made it fairly easy. In the same terminal that you used to write node tests.js or node index.js now, you just need to write learn. That's it! No matter what the lab, our Learn command will figure out where you are and run the appropriate tests and give you results.

Speaking of results... let's talk about how to read the results that tests give you.

Reading Results of Tests

If we run learn in our terminal right now, you'll get a bunch of failed tests. It will look something like this:

Output from running learn in Terminal

> js-functions-lab@0.1.0 test /Users/mbenton/Desktop/curriculum-team/js-what-is-a-test-lab
> mocha -R mocha-multi --reporter-options spec=-,json=.results.json

  what-is-a-test
    Name
      1) returns "Susan"
    Height
      2) is less than 40
    Message
      3) gives the name and height


  0 passing (293ms)
  3 failing

  1) what-is-a-test
       Name
         returns "Susan":

      Error: Expected 'Joe' to equal 'Susan'
      + expected - actual

      -Joe
      +Susan

      at assert (node_modules/expect/lib/assert.js:29:9)
      at Expectation.toEqual (node_modules/expect/lib/Expectation.js:81:30)
      at Context.<anonymous> (test/index-test.js:6:26)
      at processImmediate (internal/timers.js:456:21)

  2) what-is-a-test
       Height
         is less than 40:
     Error: Expected 74 to be less than 40
      at assert (node_modules/expect/lib/assert.js:29:9)
      at Expectation.toBeLessThan (node_modules/expect/lib/Expectation.js:156:28)
      at Context.<anonymous> (test/index-test.js:13:28)
      at processImmediate (internal/timers.js:456:21)

  3) what-is-a-test
       Message
         gives the name and height:
     Error: Expected ' is 74 inches tall' to include 'Joe'
      at assert (node_modules/expect/lib/assert.js:29:9)
      at Expectation.toInclude (node_modules/expect/lib/Expectation.js:215:28)
      at Context.<anonymous> (test/index-test.js:19:29)
      at processImmediate (internal/timers.js:456:21)



npm ERR! Test failed.  See above for more details.

Let's break this down a bit. If you look at about a third of the way down the output, you'll see a summary of how the tests went:

  0 passing (293ms)
  3 failing

That should be fairly obvious. You passed 0 tests and failed 3 tests. Not a great start, but plenty of room for improvement. Let's see how we failed the three tests.

1) what-is-a-test
       Name
         returns "Susan":

      Error: Expected 'Joe' to equal 'Susan'
      + expected - actual

      -Joe
      +Susan

      at assert (node_modules/expect/lib/assert.js:29:9)
      at Expectation.toEqual (node_modules/expect/lib/Expectation.js:81:30)
      at Context.<anonymous> (test/index-test.js:6:26)
      at processImmediate (internal/timers.js:456:21)

  2) what-is-a-test
       Height
         is less than 40:
     Error: Expected 74 to be less than 40
      at assert (node_modules/expect/lib/assert.js:29:9)
      at Expectation.toBeLessThan (node_modules/expect/lib/Expectation.js:156:28)
      at Context.<anonymous> (test/index-test.js:13:28)
      at processImmediate (internal/timers.js:456:21)

  3) what-is-a-test
       Message
         gives the name and height:
     Error: Expected ' is 74 inches tall' to include 'Joe'
      at assert (node_modules/expect/lib/assert.js:29:9)
      at Expectation.toInclude (node_modules/expect/lib/Expectation.js:215:28)
      at Context.<anonymous> (test/index-test.js:19:29)
      at processImmediate (internal/timers.js:456:21)

This is all three of the fails. If we break it down even further we can see just the test for name:

1) what-is-a-test
       Name
         returns "Susan":

      Error: Expected 'Joe' to equal 'Susan'
      + expected - actual

      -Joe
      +Susan

      at assert (node_modules/expect/lib/assert.js:29:9)
      at Expectation.toEqual (node_modules/expect/lib/Expectation.js:81:30)
      at Context.<anonymous> (test/index-test.js:6:26)
      at processImmediate (internal/timers.js:456:21)

The tests expects name to return "Susan". But if you look at the Error: Expected 'Joe' to equal 'Susan' line you can see that it received Joe and expected Susan. That makes sense! In our index.js file we have the name variable equal "Joe". If you change that line to be equal to "Susan" and then run the tests again by typing learn in the command line you should see progress!

what-is-a-test
    Name
      ✓ returns "Susan"
    Height
      1) is less than 40
    Message
      2) gives the name and height


  1 passing (544ms)
  2 failing

  1) what-is-a-test
       Height
         is less than 40:
     Error: Expected 74 to be less than 40
      at assert (node_modules/expect/lib/assert.js:29:9)
      at Expectation.toBeLessThan (node_modules/expect/lib/Expectation.js:156:28)
      at Context.<anonymous> (test/index-test.js:13:28)
      at processImmediate (internal/timers.js:456:21)

  2) what-is-a-test
       Message
         gives the name and height:
     Error: Expected ' is 74 inches tall' to include 'Susan'
      at assert (node_modules/expect/lib/assert.js:29:9)
      at Expectation.toInclude (node_modules/expect/lib/Expectation.js:215:28)
      at Context.<anonymous> (test/index-test.js:19:29)
      at processImmediate (internal/timers.js:456:21)

Woot! You passed one. Now you can go ahead and try and pass all of the other tests on your own.

Common Errors

While you are solving the other tests you may come across a few errors. Let's go over some common ones:

Expected Undefined

Error: Expected undefined to equal 'Susan'

That one says that it expected undefined to equal Susan. That makes no sense! You didn't set the name variable to undefined. Why does it think that name is equal to undefined? What that actually means is that the test couldn't find the variable name. This can happen if you by accident rename the variable. Taking a look at index.js I made this mistake: var nae = "Susan". Whoops! If I change that back to name everything works. :)

Unexpected Identifier

/Users/joe/Documents/Documents/flatiron/js-what-is-a-test-lab/index.js:2
vr name = "Susan"
   ^^^^
SyntaxError: Unexpected identifier
    at createScript (vm.js:56:10)
    at Object.runInThisContext (vm.js:97:10)
    at Module._compile (module.js:542:28)
    at Object.Module._extensions..js (module.js:579:10)
    at Module.load (module.js:487:32)
    at tryModuleLoad (module.js:446:12)
    at Function.Module._load (module.js:438:3)
    at Module.require (module.js:497:17)
    at require (internal/module.js:20:19)
    at Object.<anonymous> (/Users/joe/Documents/Documents/flatiron/js-what-is-a-test-lab/test/index-test.js:1:75)
    at Module._compile (module.js:570:32)
    at Object.Module._extensions..js (module.js:579:10)
    at Module.load (module.js:487:32)
    at tryModuleLoad (module.js:446:12)
    at Function.Module._load (module.js:438:3)
    at Module.require (module.js:497:17)
    at require (internal/module.js:20:19)
    at /Users/joe/Documents/Documents/flatiron/js-what-is-a-test-lab/node_modules/mocha/lib/mocha.js:220:27
    at Array.forEach (native)
    at Mocha.loadFiles (/Users/joe/Documents/Documents/flatiron/js-what-is-a-test-lab/node_modules/mocha/lib/mocha.js:217:14)
    at Mocha.run (/Users/joe/Documents/Documents/flatiron/js-what-is-a-test-lab/node_modules/mocha/lib/mocha.js:469:10)
    at Object.<anonymous> (/Users/joe/Documents/Documents/flatiron/js-what-is-a-test-lab/node_modules/mocha/bin/_mocha:404:18)
    at Module._compile (module.js:570:32)
    at Object.Module._extensions..js (module.js:579:10)
    at Module.load (module.js:487:32)
    at tryModuleLoad (module.js:446:12)
    at Function.Module._load (module.js:438:3)
    at Module.runMain (module.js:604:10)
    at run (bootstrap_node.js:393:7)
    at startup (bootstrap_node.js:150:9)
    at bootstrap_node.js:508:3

Woah! So many words that make no sense. Don't worry though. The most important line is the SyntaxError: Unexpected identifier line. What that means is you have some sort of typo or syntax mistake, It could be a HUGE variety of things but usually, JS will try and give you a hint. This time it's pointing to the vr name = "Susan" line of code. Take a look and read very carefully. I misspelled var. Whoops! If you fix that everything will work.

One note on this type of error is that it is sort of a catch-all. Tons and tons of problems end in that sort of error message. Whenever you see it, be sure to read over your code with a fine toothed comb...and you'll find the problem!

Type Errors

On the second test, there is a chance you might see the following error:

1) what-is-a-test
       Height
         is less than 40:
     Error: The "actual" argument in expect(actual).toBeLessThan() must be a number
      at assert (node_modules/expect/lib/assert.js:29:9)
      at Expectation.toBeLessThan (node_modules/expect/lib/Expectation.js:156:28)
      at Context.<anonymous> (test/index-test.js:13:28)
      at processImmediate (internal/timers.js:456:21)

This error is slightly different than the last two. In this case, the test is giving us a unique message because it recognizes a problem. If we look at this test in test/index-test.js, we see this:

  describe('Height', () => {
    it('is less than 40', () => {
      expect(index.height).toBeLessThan(40)
    })
  })

The word "actual" is no where to be found - index.height is what is being tested. The test expects index.height to be less than 40. The error message is telling us that index.height must be a number. If you're seeing this, make sure that you have set index.height to be equal to the number 40, not the string "40". Ruby will interpret the value as a string due to the quotation marks wrapping it.

Conclusion

Once you have all three tests passing, run learn submit to register completion. Congratulations, you've solved your first tests! On to many more!

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