load data from module before test executes

Question

(I asked this question recently and accepted an answer but it's still not what I need.) I really need to create dynamic tests from data loaded from a module. Each item from the array will have it's own describe statement with certain protractor actions. My previous post has an answer that says to use an it statement, but I can't do that because there's too much going on.

My main problem is that the data doesn't get loaded in time for the describe. I had another suggestion to use VCR.js or something similar but I don't think those will work because I'm using a module. Is there a way I can save the data to a separate file and load it in? Would that be a good way to go?

var data = require('get-data'); //custom module here

describe('Test', function() {
  var itemsArr;
  beforeAll(function(done) { 
    data.get(function(err, result) {
      itemsArr = result; //load data from module
      done();
    });
  })

  //error: Cannot read property 'forEach' of undefined
  describe('check each item', function() {
    itemsArr.forEach(function(item) {
      checkItem(item);
    });
  });

  function checkItem (item) {
    var itemName = item.name;
    describe(itemName, function() {
      console.log('describe');
      it('should work', function() {
        console.log('it');
        expect(true).toBeTruthy();
      });
    });
  }

});

UPDATE:

I used Eugene's answer and came up with this. I can't test each individual study how I want because the it statement doesn't fire. Is this problem even solvable??

describe('check each item', function () {
   it('should load data', function (done) {
      browser.wait(itemsPromise, 5000);
     itemsPromise.then(function(itemsArr) {
       expect(itemsArr).toBeTruthy();
       studyArr = itemsArr.filter(function (item) {
         return item.enabled && _.contains(item.tags, 'study');
       });
       studyCount = studyArr.length;
       expect(studies.count()).toEqual(studyCount);
       checkItems(studyArr);
       done();
     });
   });
   function checkItems (itemsArr) {
     itemsArr.forEach(function (item) {
       describe(item.id, function () {
        console.log('checkItems', item.id);
        // doesn't work
         it('should work', function (done) {
           expect(false).toBeTruthy();
           done();
         });
       });
     });
   }
 });

Answer 1

You're trying to do something that Jasmine does not allow: generating tests after the test suite has started. See this comment on an issue of Jasmine:

Jasmine doesn't support adding specs once the suite has started running. Usually, when I've needed to do this, I've been able to know the list of options ahead of time and just loop through them to make the it calls. [...]

("adding specs" === "adding tests")

The point is that you can generate tests dynamically but only before the test suite has started executing tests. One corollary of this is that the test generation cannot be asynchronous.

Your second attempt does not work because it is trying to add tests to a suite that is already running.

Your first attempt is closer to what you need but it does not work either because describe calls its callback immediately, so beforeAll has not run by the time your describe tries to generate the tests.

Solutions

It all boils down to computing the value of itemsArr before the test suite start executing tests.

You could create a .getSync method that would return results synchronously. Your code would then be something like:

var data = require('get-data'); //custom module here
var itemsArr = data.getSync();

describe('Test', function() {
  describe('check each item', function() {
    itemsArr.forEach(function(item) {
      checkItem(item);
    });
  });

[...]

If writing .getSync function is not possible, you could have an external process be responsible for producing a JSON output that you could then deserialize into itemsArr. You'd execute this external process with one of the ...Sync functions of child_process.

Here's an example of how the 2nd option could work. I've created a get-data.js file with the following code which uses setTimeout to simulate an asynchronous operation:

var Promise = require("bluebird"); // Bluebird is a promise library.

var get = exports.get = function () {
    return new Promise(function (resolve, reject) {
        var itemsArr = [
            {
                name: "one",
                param: "2"
            },
            {
                name: "two",
                param: "2"
            }
        ];
        setTimeout(function () {
            resolve(itemsArr);
        }, 1000);
    });
};

// This is what we run when were are running this module as a "script" instead
// of a "module".
function main() {
    get().then(function (itemsArr) {
        console.log(JSON.stringify(itemsArr));
    });
};

// Check whether we are a script or a module...
if (require.main === module) {
    main();
}

Then, inside the spec file:

var child_process = require('child_process');

var itemsArr = JSON.parse(child_process.execFileSync(
    "/usr/bin/node", ["get-data.js"]));

describe('Test', function() {
    itemsArr.forEach(function(item) {
        checkItem(item);
    });

    function checkItem (item) {
        var itemName = item.name;
        describe(itemName, function() {
            console.log('describe');
            it('should work', function() {
                console.log('it');
                expect(true).toBeTruthy();
            });
        });
    }
});

I've tested the code above using jasmine-node. And the following file structure:

.
├── data.js
├── get-data.js
└── test
    └── foo.spec.js

./node_modules has bluebird and jasmine-node in it. This is what I get:

$ ./node_modules/.bin/jasmine-node --verbose test 
describe
describe
it
it

Test - 5 ms

    one - 4 ms
        should work - 4 ms

    two - 1 ms
        should work - 1 ms

Finished in 0.007 seconds
2 tests, 2 assertions, 0 failures, 0 skipped

Answer 2

Is your get-data module doing some browser things with protractor? If so, you will need to set/get itemsArr within the context of the controlFlow. Otherwise it will read all the code in the get-data module, but defer its execution and not wait for it to finish before moving right along to those expect statements.

var data = require('get-data'); //custom module here
var itemsArr;

describe('Test', function() {
  beforeAll(function() {
    // hook into the controlFlow and set the value of the variable
    browser.controlFlow().execute(function() {
      data.get(function(err, result) {
        itemsArr = result; //load data from module
      });
    });
  });

  //error: Cannot read property 'forEach' of undefined
  describe('check each item', function() {
    // hook into the controlFlow and get the value of the variable (at that point in time)
    browser.controlFlow().execute(function() {
      itemsArr.forEach(function(item) {
        checkItem(item);
      });
    });
  });

  function checkItem (item) {
    var itemName = item.name;
    describe(itemName, function() {
      console.log('describe');
      it('should work', function() {
        console.log('it');
        expect(true).toBeTruthy();
      });
    });
  }

});

Answer 3

Try to use a promise, something like:

  var deferred = protractor.promise.defer();
  var itemsPromise = deferred.promise;
  beforeAll(function() { 
    data.get(function(err, result) {
      deferred.fulfill(result);
    });
  })

And then:

  describe('check each item', function() {
    itemsPromise.then(function(itemsArr) {
        itemsArr.forEach(function(item) {
          checkItem(item);
        });
    });
  });

Another solution I can think of is to use browser.wait to wait until itemsArr becomes not empty.