I've written a lot of django applications and become accustomed to extending unittest.TestCase and running python manage.py test app_name. Is there a similarly simple way to unit test Kanso apps? Please provide a minimal example.
Thanks.
How to Write Unit Tests for Kanso
Asked Answered
Make sure you check out the answers from JasonSmith, Caolan, and Ryan Ramage. They are all correct and useful. I accepted the answer from JasonSmith because it stands on its own best. –
Devilry
Thanks. But Caolan's point is very insightful. My technique might be "unit tests" strictly speaking. But ultimately you want functional or integration tests to confirm how the browsers will behave. –
Vernice
Kanso apps are CouchDB apps. However the best bang-for-buck is to ignore CouchDB for now. The important thing is this: Kanso apps are Node.js apps. Test them the same way you would test a Node.js app. Test that they adhere to the documented CouchDB API and you will be fine.
Ideally, we might want to run tests actually in CouchDB. The JavaScript engines are different (V8 vs. SpiderMonkey); the environments are different. However in practice, it is so much easier to test Node.js code. (Also, a whole class of JavaScript bugs are absent on both platforms: third-party code setting global variables, changing built-in types, changing prototypes—those are all browser issues. Node.js and CouchDB are both pristine and predictable.)
Example
Let's make a simple Couch app that outputs "Hello world" in a _show function.
The kanso.json file:
{ "name" : "hello_world"
, "version": "0.1.0"
, "description": "A simple hello-world Couch app"
, "dependencies": { "node-couchapp": "~0.8.3" }
, "app": "app"
}
Next run kanso install which will pull in the "node-couchapp" dependency. (Notice how using the kanso command is similar to using the npm command.)
Let's make a very simple Couch app, in ./app.js:
// A Couch app that just says hello in a _show function.
module.exports = {
'shows': {
'hello': function(doc, req) {
var who = req.query.who || "world"
return "Hello, " + who
}
}
}
I ran kanso push http://example.iriscouch.com/so_hello and I can see my app here:
- http://example.iriscouch.com/so_hello/_design/hello_world/_show/hello
- http://example.iriscouch.com/so_hello/_design/hello_world/_show/hello?who=Stack+Overflow
Adding Tests
I like node-tap so let's use that. But the main point is, this is just some Node.js code. Test it using whatever method your prefer.
First, a quick package.json file:
{ "name" : "hello_world"
, "description": "A simple hello-world Couch app"
, "version": "0.1.0"
, "private": true
, "devDependencies": { "tap": "~0.2.3" }
}
Run npm install to get the node-tap package. (And I always have ./node_modules/.bin in my $PATH when I work on Node.js. Rather than a global install, I like to have everything I need right there in the project.
Next, perhaps a test/show_function.js file:
var tap = require('tap')
tap.test('The Couch app loads', function(t) {
t.doesNotThrow(load_app, 'No problem loading the app.js file')
t.end()
function load_app() {
var app = require('../app')
}
})
tap.test('The show function', function(t) {
var app = require('../app')
, hello = app.shows.hello
t.type(hello, 'function', 'Show function "hello" in the couch app')
var doc = {}
, null_req = {'query':{}}
, john_req = {'query':{'who':'John Doe'}}
t.equal(hello(doc, null_req), 'Hello, world', '"Hello world" by default')
t.equal(hello(doc, john_req), 'Hello, John Doe', 'Supports ?who query string')
t.end()
})
Test it by running tap test:
$ tap test
ok test/show_function.js ................................ 5/5
total ................................................... 5/5
ok
I'll change the code to return "Hello, world" hard-coded (i.e., ignore the req.query.who parameter). Notice the failing test:
$ tap test
not ok test/show_function.js ............................ 4/5
Command: "node" "show_function.js"
ok 1 No problem loading the app.js file
ok 2 Show function "hello" in the couch app
ok 3 "Hello world" by default
not ok 4 Supports ?who query string
---
file: /private/tmp/j/test/show_function.js
line: 23
column: 5
stack:
- getCaller (/private/tmp/j/node_modules/tap/lib/tap-assert.js:403:17)
- assert (/private/tmp/j/node_modules/tap/lib/tap-assert.js:19:16)
- Function.equal (/private/tmp/j/node_modules/tap/lib/tap-assert.js:160:10)
- Test._testAssert [as equal] (/private/tmp/j/node_modules/tap/lib/tap-test.js:86:16)
- Test.<anonymous> (/private/tmp/j/test/show_function.js:23:5)
- Test.<anonymous> (native)
- Test.<anonymous> (events.js:88:20)
- Test.emit (/private/tmp/j/node_modules/tap/lib/tap-test.js:103:8)
- GlobalHarness.<anonymous> (/private/tmp/j/node_modules/tap/lib/tap-harness.js:86:13)
- Array.0 (native)
found: Hello, world
wanted: Hello, John Doe
diff: |
FOUND: Hello, world
WANTED: Hello, John Doe
^ (at position = 7)
...
ok 5 test/show_function.js
1..5
# tests 5
# pass 4
# fail 1
total ................................................... 4/5
not ok
Incidentally, I have converted all my work to Kanso specifically because it is so much easier to unit test. –
Vernice
I have some projects that may help showcase testing kanso apps:
Dashboard Core Project
https://github.com/ryanramage/dashboard-core
Features:
- Travis Support.
- PhantomJS headless testing using NodeUnit
- Since this is a module, we have a test folder, that is a seperate kanso app that uses the module. Note in the packages folder there is a symlink back to the root of the project.
Node-Couchapp Project
https://github.com/kanso/node-couchapp
- Travis support
- This time multiple test kanso projects in the kanso folder. Again using the symlink trick in the package directory
You also might want to have a peek at: github.com/kanso/couch-fakerequest for help testing shows, lists, and update functions. –
Imhoff
Like JasonSmith, I also recommend you test using Node.js where possible. However, due to the nature of CouchApps you often end up having to write unit tests to run in the browser, either because they interact with browser APIs you don't want to mock or because you need to test it works in a range of browsers.
When doing browser-based unit tests I use a few little Kanso packages I hacked together to automatically present an interface for running nodeunit test suites. It's a bit rough around the edges at the moment but gets the job done.
kanso.json
Add nodeunit and nodeunit-testrunner packages to your kanso.json file and run kanso install to fetch them from the repositories.
{
"name": "example",
"version": "0.0.1",
"description": "example app with unit tests",
"modules": ["lib", "tests"],
"load": "lib/app",
"dependencies": {
"modules": null,
"properties": null,
"nodeunit": null,
"nodeunit-testrunner": null
}
}
Notice that I've included the 'tests' directory as a module path. Any modules dropped into that directory will be used as nodeunit test suites and displayed by the nodeunit-testrunner UI.
Rewrites
You need to manually add the nodeunit-testrunner package's rewrites to your app, in my example that means editing lib/app.js to look like the following:
exports.rewrites = [
require('nodeunit-testrunner/rewrites')
];
Add some tests
Assuming we have a module lib/foo.js that looks like this:
exports.hello = function (name) {
return 'hello ' + name;
};
We could add a test by adding a module at tests/test-foo.js (this can be named anything so long as it's inside the tests directory).
var foo = require('lib/foo');
exports['test for foo.hello'] = function (test) {
test.equal(foo.hello('bar'), 'hello bar');
test.done();
};
If you then push your app and visit http://localhost:5984/example/_design/example/_rewrite/test in the browser you will be presented with a basic interface for running the test suites in the tests directory, either individually or all of them one after another.
Hope that helps.
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