You understand how to read tests, now it's time for how to run the tests. We've made it fairly easy. In the same terminal that you used to write nodejs tests.js or nodejs 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.
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/joe/Documents/Documents/flatiron/js-what-is-a-test-lab
> mocha -R mocha-multi --reporter-options nyan=-,json=.results.json
0 -_-__,------,
3 -_-__| /\_/\
0 -_-_~|_( x .x)
-_-_ "" ""
0 passing (612ms)
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.it (test/index-test.js:6:26)
2) what-is-a-test Height is greater 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.it (test/index-test.js:13:28)
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.it (test/index-test.js:19:29)
npm ERR! Test failed. See above for more details.
Let's break this down a bit. If you look at the line under the cat (I love programmers) you'll see a summary of how the tests went:
0 passing (612ms)
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.it (test/index-test.js:6:26)
2) what-is-a-test Height is greater 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.it (test/index-test.js:13:28)
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.it (test/index-test.js:19:29)
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.it (test/index-test.js:6:26)
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!
1 -_-__,------,
2 -_-__| /\_/\
0 -_-_~|_( x .x)
-_-_ "" ""
1 passing (953ms)
2 failing
1) what-is-a-test Height is greater 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.it (test/index-test.js:13:28)
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.it (test/index-test.js:19:29)
Woot! You passed one. Now you can go ahead and try and pass all of the other tests on your own.
While you are solving the other tests you may come across a few errors. Let's go over some common ones:
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. :)
/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 you code with a fine toothed comb...and you'll find the problem!