unit testing

Unit testing JSON files in assets folder of Android App

So here is the scenario, your android app has a lot of json files in the assets folder that are used to load some data when in first runs.
You are writing some unit tests, and want to make sure the integrity of the data in the assets/*.json are preserved.

You’d assume, that reading JSON files should not involve using the Android Runtime in any way, and we should be able to read JSON files in local JVM as well. But you’re wrong. The JSONObject and JSONArray classes of Android are part of android.jar, and hence

 
JSONObject myJson = new JSONObject(someString);

The above code will not work when running unit tests on local JVM.

Fortunately, our codebase already using Google’s GSoN library to parse JSON, and that works on local JVM too (because GSoN is a core Java library, not specifically an Android library).

Now the second problem that comes is that when running unit tests on local JVM we do not have the getResources() or getAssets() functions.
So how do we retrieve a file from the assets folder ?

So what I found out (after a bit of trial and error and poking around with various dir paths), is that the tests are run from the app folder (app being the Android application module – it is named app by default by Android Studio, though you might have had named it differently)

So in the tests file you can define at the beginning

    public static final String  ASSET_BASE_PATH = "../app/src/main/assets/";

And also create the following helper function

    public String readJsonFile (String filename) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(new FileInputStream(ASSET_BASE_PATH + filename)));
        StringBuilder sb = new StringBuilder();
        String line = br.readLine();
        while (line != null) {
            sb.append(line);
            line = br.readLine();
        }

        return sb.toString();
    }

Now wherever you need this JSON data you can just do the following 

        Gson gson = new GsonBuilder().create();
        events = gson.fromJson(readJsonFile("events.json"),
                Event.EventList.class);
        eventDatesList = gson.fromJson(readJsonFile("eventDates.json"), EventDates.EventDatesList.class);
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Unit testing nodejs with Mocha and Chai

There are a lot of unit testing frameworks available for Javascript, Jasmine and Karma being some of the older and more popular ones.

Jasmine and Karma, though are, originally designed for browser-side JS, and hence, frameworks like NodeUnit and Mocha have become more popular with server-size JS.
We needed code coverage reports to work after the unit tests, and the Jasmine-Node reports were not sufficient, so we just moved to using Mocha.

When using Mocha, we can use some assert library (which is not necessary, but makes life a hell lot easier). We are using chai at the open-event-webapp..

First of all install mocha globally –

npm install -g mocha

And write your tests in the test/ folder that mocha by default considers as the folder containing your test specs. For example we have our tests here – https://github.com/fossasia/open-event-webapp/tree/master/test

Writing a simple mocha test is as easy as this –

var assert = require('chai').assert;
describe('Array', function() {
  describe('#indexOf()', function() {
    it('should return -1 when the value is not present', function() {
      assert.equal(-1, [1,2,3].indexOf(5));
      assert.equal(-1, [1,2,3].indexOf(0));
    });
  });
});

The first parameter inside describe() is just to show the tests in a aesthetic way in the console.

You can see our tests described in this file  – https://github.com/fossasia/open-event-webapp/blob/master/test/serverTest.js

And attached below is an screenshot of the terminal after I have run the command mocha in the root of my project

Screenshot from 2016-07-10 04-42-26

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