So I'm trying to teach myself Jasmine (for node) by working through a tutorial for a Mongoose project, TDD style, writing tests for what each step is supposed to accomplish, then following the actual tutorial, etc.
Of course, my first test is failing.
app.js at this point is two lines:
var mongoose = require('mongoose');
console.log(mongoose.version);
This runs fine. My test however, still fails:
var app = require('../src/app.js');
describe('App startup', function() {
it('loads mongoose', function() {
expect(app.mongoose.version).toBeDefined();
});
it('loads jasmine-jquery', function() {
expect($).toBeDefined();
});
});
Results in
Failures:
1) App startup loads mongoose
Message:
TypeError: Cannot read property 'version' of undefined
Stacktrace:
TypeError: Cannot read property 'version' of undefined
at null.<anonymous> (/home/jbhelfrich/mongooseBlog/spec/init.spec.js:5:36)
(The jquery test is, of course, expected to fail still at this point.) I've tried it with and without the 'app.' in the expect clause, but I get the same error--the test suite doesn't see the internals of app.js. But I know it's loading the app.js file correctly, because it's running it--the console.log output appears ahead of the test results.
So I suspect I've misunderstood something fundamental about scope, or some other rookie mistake, but I'm not sure what that is.
Node.js is structured into modules. If you want a a module's properties to be accessible, that module's properties must be defined in the module.exports variable. This is what an export might look like (note that exports references module.exports):
var mongoose = require('mongoose');
console.log(mongoose.version);
exports.mongoose = mongoose;
Then when you've used require() on a file with the code shown above, the variables will be set, where app is equivalent to module.exports in the module that is being loaded:
var app = require('../src/app.js');
console.log(app.mongoose.version);
Related
I am trying out Stitch, a serverless/hosted JavaScript environment from MongoDB. My main purpose is to help me learn modern JavaScript, but I am trying to write a useful app as well.
I have written the following function, and saved it in my Stitch app. I believe this follows the documented way to write functions in Stitch, and I have tested it from the Stitch administration console:
exports = function(query){
const http = context.services.get("HTTP");
const urlBase = context.values.get("stackOverflowApiUrl");
const options = [
'order=desc',
'sort=activity',
'site=stackoverflow',
'q=' + encodeURIComponent(query),
'user=472495',
'filter=!--uPQ.wqQ0zW'
];
return http
.get({ url: urlBase + '?' + options.join('&') })
.then(response => {
// The response body is encoded as raw BSON.Binary. Parse it to JSON.
const ejson_body = EJSON.parse(response.body.text());
return ejson_body.total;
});
};
This code is pretty simple - it obtains an http object for making external API fetches, and obtains a configuration value for a URL urlBase to contact (resolving to https://api.stackexchange.com/2.2/search/excerpts) and then makes a call to the Stack Overflow Data API. This runs a search query against my user and returns the number of results.
So far so good. Now, I want to call this function locally, in Jest. To do this, I have installed Node and Jest in a local Docker container, and have written the following test function:
const callApi = require('./source');
test('Simple fetch with no user', () => {
expect(callApi('hello')).toBe(123);
});
This fails, with the following error:
~ # jest
FAIL functions/callApi/source.test.js
✕ Simple fetch with no user (3ms)
● Simple fetch with no user
TypeError: callApi is not a function
2 |
3 | test('Simple fetch with no user', () => {
> 4 | expect(callApi('hello')).toBe(123);
| ^
5 | });
6 |
at Object.<anonymous>.test (functions/callApi/source.test.js:4:12)
Test Suites: 1 failed, 1 total
Tests: 1 failed, 1 total
Snapshots: 0 total
Time: 1.418s
Ran all test suites.
(In fact I was expecting it to fail, since it contains a global object context that Jest does not have access to. I will work out how to mock that later, but for now Jest cannot even see the function at all).
I suspect I can see the reason - in the Jest introduction docs, one has to do this for the SUT:
module.exports = function() { ... }
However the Stitch docs seem to require functions to be defined as:
exports = function() { ... }
I do not have a background in JavaScript to understand the difference. I could try module.exports in Stitch, but I would rather not, since this would either not work now, or cause a breakage in the future. Can Jest be instructed to "see" bare exports without the module prefix?
Incidentally, I have picked Jest because it is popular, and because some of my JavaScript colleagues vouch for it. However, I am not wedded to it, and would be happy to use something else if it is known to be better for Stitch development.
Update
Following the useful answer from jperl below, I find that the following construction is not possible in Stitch:
module.exports = exports = function() {}
I also cannot do this:
exports = function() {}
module.exports = exports
If I try either, I get the following error:
runtime error during function validation
So it looks like I have to get Jest to work without module.exports, or create a glue file that imports the exports version into module.exports, with the main file being used by Stitch, and the glue importer being used by Jest.
I suggest you to read this thread. And you're right in thinking it has to do with modules.exports vs exports. The thing is that module.exports and exports first point to the same thing. So something like this works:
//modify the same object that modules.exports is pointing to
exports.a = {}
exports.b = {}
but this won't:
exports = {}
Why? Because now exports points to something else than module.exports so what you're doing has no effect at all.
Update
Following some updates in the comments, we came to the view that Stitch does not seem to support the export format that Jest requires.
This is an addendum to jperl's answer, to show how I got Jest working while respecting Stitch's limitations.
Firstly, it is worth noting how a Stitch application is laid out. This is determined by the import/export format.
auth_providers/
functions/
function_name_1/
config.json
source.js
function_name_2/
config.json
source.js
...
services/
values/
The config.json file is created by Stitch remotely, and is obtained through a export. This contains ID information to uniquely identify the function in the same folder.
I believe it is common JavaScript practice to mix tests with source code, so I am following that style (I am new to modern JS, and I confess I find this style untidy, but I am running with it nevertheless). Thus I add a source.test.js file in each function folder.
Finally, since there is a discrepancy between what Stitch requires and what Jest requires, I have written a script to create a source code file under _source.js in each function folder.
So, each folder will contain these files (the underscore files will probably be ignored by Git, as they will always be generated):
_source.js
config.json
source.js
source.test.js
In order to create the underscored copies, I am using this shell script:
#!/bin/bash
# Copy all source.js files as _source.js
for f in $(find functions/ -name source.js); do cp -- "$f" "$(dirname $f)/_$(basename $f)"; done
# Search and replace in all _source.js files
for f in $(find functions/ -name _source.js); do sed -i -e 's/exports =/module.exports =/g' $f; done
A bit hacky perhaps, but it works!
I have the following Node.js project (which is a Minimal Working Example of my problem):
module1.js:
module.exports = function() {
return "this is module1!";
};
module2.js:
var module1 = require('./module1');
module.exports = function() {
return module1()+" and this is module2!";
};
server.js:
var module2 = require('./module2');
console.log(module2()); // prints: "this is module1! and this is module2!"
Now I want to create a client.html file that will also use module2.js. Here is what I tried (and failed):
naive version:
<script src='module2.js'></script>
<script>alert(module2());</script> // should alert: "this is module1! and this is module2!"
This obviously doesn't work - it produces two errors:
ReferenceError: require is not defined.
ReferenceError: module2 is not defined.
Using Node-Browserify: After running:
browserify module2.js > module2.browserified.js
I changed client.html to:
<script src='require.js'></script>
<script>
var module2 = require('module2');
alert(module2());
</script>
This doesn't work - it produces one error:
ReferenceError: module2 is not defined.
Using Smoothie.js by #Torben :
<script src='require.js'></script>
<script>
var module2 = require('module2');
alert(module2());
</script>
This doesn't work - it produces three errors:
syntax error on module2.js line 1.
SmoothieError: unable to load module2 (0 )
TypeError: module2 is not a function
I looked at require.js but it looks too complicated to combine with Node.js - I didn't find a simple example that just takes an existing Node.js module and loads it into a web page (like in the example).
I looked at head.js and lab.js but found no mention of Node.js's require.
So, what should I do in order to use my existing Node.js module, module2.js, from an HTML page?
The problem is that you're using CJS modules, but still try to play old way with inline scripts. That won't work, it's either this or that.
To take full advantage of CJS style, organize your client-side code exactly same way as you would for server-side, so:
Create client.js:
var module2 = require('./module2');
console.log(module2()); // prints: "this is module1! and this is module2!"
Create bundle with Browserify (or other CJS bundler of your choice):
browserify client.js > client.bundle.js
Include generated bundle in HTML:
<script src="client.bundle.js"></script>
After page is loaded you should see "this is module1! and this is module2!" in browser console
You can also try simq with which I can help you.
Your problems with Smoothie Require, were caused by a bug (https://github.com/letorbi/smoothie/issues/3). My latest commit fixed this bug, so your example should work without any changes now.
I am having a hard time trying to run tests with Mocha and RequireJS in the browser.
My attempt is based on https://gist.github.com/michaelcox/3800736
I had to diverge from that example, because my main issue is that require('mocha') always errors with "Module name "lib/mocha" has not been loaded yet for context".
But somehow magically I see that global Mocha is instantiated. I invoke it as a constructor, but the run of new Mocha() does not prepare the interface (describe, etc.)
I see that the problem is that an inner call to
this._ui = this._ui(this.suite);
leaves this._ui undefined, apparently because array this.suite.tests is empty, which is explainable as I still have to read the test suite file.
Here are the details. If anyone can shed some light, I'll be very grateful.
I start from a single HTML tag loading require.js with a data-main.
<script data-main="./js_modular/spec-runner" src="./js_modular/lib/require.js"></script>
My data-main file (not working!) is the following:
require.config({
'paths': {
'mocha': './lib/mocha',
'chai': './lib/chai',
'sinon': './lib/sinon-1.11.1'
}
});
define(['require', 'exports', 'mocha'], (function(require, exports, mocha) {
// mocha is undefined, but Mocha is not
var mocha = new Mocha({ ui: 'bdd' }); // mocha misses the characteristic methods of the bdd interface, though...
require([
'./geiesadts_test', // load of test file fails because describe is undefined
], function(require) {
mocha.run(); // never got till here :-(
});
}));
Thank you for your attention.
I cannot seem to access a global variable in Ext.application after I do a production or test build with Cmd 4. This happens during the first application launch. I have read other similar threads but there is nothing new in there that can solve my problem for whatever reason.
Before I started using Cmd, I would run my application from a server against the application directory, and things ran just fine. I had no problems with my other files picking up the global variables.
Now that I have moved to Cmd 4 / ST2.3.1, the test and production builds get built into one big app.js file. So it seems that when code that is earlier in the js file calls a global variable, it cannot find it, with the console exception:
Uncaught TypeError: Cannot read property 'targetServer' of undefined
This happens during the first application launch, and the app just hangs. The loading indicators are not even removed. I noticed that the Ext.application code is at the end of the app.js. Could it be some code is launching before the application is fully loaded?
In my app.js, I have the following. This is last in my app.js at line 76623. The global variable not being read is "targetServer":
Ext.application({
name: 'qxtapp',
targetServer: 'http://192.168.1.70:8080'
...
});
One of my stores looks like this. This is where I get the exception. The below code is earlier in my app.js, at line 70742:
Ext.define('qxtapp.store.AccountsListStore', {
extend : Ext.data.Store ,
xtype : 'accountsListStore',
config: {
model: 'qxtapp.model.AccountsList',
data: [
{ accountName: qxtapp.app.targetServer+'/account_one' },
// ^ Causes exception- cannot read property "targetServer"
// of undefined
{ accountName: qxtapp.app.targetServer+'/account_two' },
...
]
}
})
Any idea what I'm missing here? Any help is greatly appreciated.
Thanks!
This is an order-of-operations error.
In development, your Ext.application() code (in app.js) is run first because any other classes (e.g. qxtapp.store.AccountsListStore) are loaded dynamically after the browser physically reads app.js.
But when you use Cmd to bundle your classes together, the resulting single JS file is read entirely at once by the browser. What happens is that the Ext.define() methods all run BEFORE Ext.application()... so qxtapp.app isn't yet assigned.
The easiest way to circumvent this problem is to use a true global variable, not just a property assigned to the global "app" object (in app.js):
var TARGET_SERVER = 'http://192.168.1.70:8080';
Ext.application({
//...
})
And in your other classes...
Ext.define('qxtapp.store.AccountsListStore', {
extend : Ext.data.Store ,
xtype : 'accountsListStore',
config: {
model: 'qxtapp.model.AccountsList',
data: [
{ accountName: TARGET_SERVER + '/account_one' }
//...
]
}
});
I'm making my first attempt at Javascript testing, with Buster.js
I've followed the instructions at the Buster site to run "states the obvious" test. However, I haven't been able to import any of my existing .js files into the tests.
For instance, I have a file js/testLibrary.js, containing:
function addTwo(inp) {
return inp+2;
}
and a file test/first-test.js, containing:
// Node.js tests
var buster = require("buster");
var testLibrary = require("../js/testLibrary.js");
var assert = buster.referee.assert;
buster.testCase("A module", {
"Test The Library": function() {
result = addTwo(3);
console.log(result);
assert(true, 'a message for you');
}
});
Running buster-test gives:
Error: A module Test The Library
ReferenceError: addTwo is not defined
[...]
Replacing result = addTwo(3); with result = testLibrary.addTwo(3); gives:
Error: A module Test The Library
TypeError: Object #<Object> has no method 'addTwo'
[...]
I'm probably missing something really basic, but at present, I'm completely stumped. Can someone point me in the right direction?
That is because you are not exporting this function from the module.
Take a look at that:
http://nodejs.org/api/modules.html#modules_module_exports