jasminum

v0.0.6

Published

2 years ago

A light, modular, promissory, isomorphic Jasmine test scaffold clone

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hthetiot

kriskowal

jasmine test testing bdd promise isomorphic

Jasminum

“Jasmine (taxonomic name Jasminum /ˈdʒæzmɨnəm/) is a genus of shrubs and vines in the olive family (Oleaceae)” — Wikipedia

Jasminum is a JavaScript testing scaffold. Jasminum is designed to accept Jasmine 1.3 “specs” with very little modification. However, it has a minimal but modular and extensible core, supports and uses promises for asynchronous tests, and has an “isomorphic” API, meaning Jasminum tests can be run without modification between Node.js and browsers using CommonJS module loaders including Browserify, Mr, or Mop.

Jasminum is built for debugging and isolation, not merely a regression trip-wire. Instead of trying to patch the universe so that all context gets funneled into pretty reports, Jasminum reports to the console. You do not need to isolate which test was running when that message got dumped to the console. Jasminum includes reporters for Node.js, PhantomJS, and browser based tests. The reporter only highlights lines of interest. It highlights the spec in stack traces. The test summary only shows green if all tests pass. The test summary only shows red if any tests fail. The test summary only highlights skipped tests if there were any.

First, write a test.

// test/my-test.js
describe("my library", function () {
    it("should work", function () {
        expect(10).toBeLessThan(20);
    });
});

You can install the jasminum command using npm. I recommend installing Jasminum in your project so the version gets saved in your package.json and so you can use different versions in your various projects.

❯ npm install jasminum --save-dev

Or, if necessary, install globally.

❯ [sudo] npm install jasminum -g

Use jasminum to run your test. jasminum will run all test files specified, or all *-test.js and *-spec.js files within each specified directory.

❯ jasminum test
1 tests passed
1 assertions passed
0 tests failed
0 assertions failed
0 errors
0 tests skipped

The results will be colored to draw your attention either to passed, failed, or skipped tests depending on the situation. You can use iit and ddescribe to focus on certain tests, skipping all others. You can use xit and xdescribe to skip certain tests.

You can use the -f command line flag to only show information about failed tests. Because the test runner does not know whether to show the name of the test until it fails, test names, and all of their parent suite names, will be logged after the test fails instead of before. Arrows draw your attention to this nuance.

With PhantomJS installed, Jasminum can run the same tests in the PhantomJS headless browser. The interface and reports are identical.

❯ jasminum-phantom test
1 tests passed
1 assertions passed
0 tests failed
0 assertions failed
0 errors
0 tests skipped

You can create an “isomorphic” test runner that you can use to run tests in Node.js directly, or using a browser module loader, or to measure test coverage.

// test/index.js
var Suite = require("jasminum");
new Suite("my tests").describe(function () {
    require("./my-test");
}).runAndReport().done();

Create a test script in your package.json:

{
    "scripts": {
        "test": "node test/index.js"
    }
}

Now, npm test will run your tests.

To run the same tests in a web browser, use npm install mr@~0.13.3 --save-dev and use the following HTML test scaffold.

<!-- test/index.html -->
<!DOCTYPE html>
<html>
    <head>
        <meta charset="utf-8">
        <link rel="stylesheet" type="text/css"
            href="../node_modules/jasminum/jasminum.css">
        <script
            src="../node_modules/mr/bootstrap.js" data-package=".."
            data-module="test/index"></script>
    </head>
    <body>
    </body>
</html>

The page under test will be blank. You can use this space as a stage for your tests. The test runner reports directly to your web inspector console. It will change the background color to grey while tests are running, red when the first test fails, or green if all tests complete without any failures.

To get test coverage measurements, use npm install istanbul@~0.2.4 --save-dev and npm install opener --save-dev and add a script to your package.json. This will cause npm run cover to run coverage and display the results.

{
    "devDependencies": {
        "jasminum": "~1.0",
        "mr": "~0.13.3",
        "istanbul": "~0.2.4",
        "opener": "*"
    },
    "scripts": {
        "test": "jasminum test",
        "test:phantom": "jasminum-phantom test",
        "cover": "istanbul cover test/index.js && istanbul report html && opener coverage/index.html"
    }
}

Promissory

Jasminum supports asynchronous tests that either use a done callback or return a promise.

describe("an asynchronous task", function () {
    it("waits for one second using done", function (done) {
        setTimeout(done, 1000);
    });
    it("waits for one second using a promise", function () {
        return Q().delay(1000);
    });
});

If a test returns a promise, it is expected to be fulfilled with undefined.

Jasminum does not support runs or waitsFor.

Modular

At time of writing, Jasminum weighs less than a KLOC. This is largely because it delegates large responsibilities to Montage Collections and the Q promise library.

Jasminum is loosely coupled to Q. You can substitute any promise library that supports a Promise constructor and a Promise.resolve method, per ECMAScript 6. Create a constructor that inherits from Jasminum’s Suite and override its Promise property, or just pass Promise as an option to suite.runAndReport(options).

The Collections library establishes foundations that Jasminum employs for comparing values, particularly polymorphic Object.equals, Object.compare, and Object.has operators, as well as the non-polymorphic Object.is operator. These do not behave exactly the same way as Jasmine, but are designed with extensibility in mind both within and beyond testing. Partcularly, “any” objects simply override their “equals” method to recognize any object of the same type as equivalent.

“Isomorphic”

“The scare quotes will come off when I say they come off.” — Math

Jasminum supports an “isomorphic” test runner. The following test can be run in Node.js with node test/index.js

// test/index.js
var Suite = require("jasminum");
var suite = new Suite("Q").describe(function () {
    require("./q");
    require("./eta");
    require("./traces");
    require("./never-again");
    require("./node");
    require("./queue");
});
suite.runAndReport().done();

It can also be run with Mr with no modification.

<!-- test/index.html -->
<!DOCTYPE html>
<html>
    <head>
        <meta charset="utf-8">
        <link rel="stylesheet" type="text/css"
            href="../node_modules/jasminum/jasminum.css">
        <script
            src="../node_modules/mr/boot.js" data-package=".."
            data-module="test/index"></script>
    </head>
    <body>
    </body>
</html>

Debuggable

The default test reporter for Node.js and for browsers are designed with debugging in mind. Either way, all results are reported to the console as they are executed. The scaffold logs messages between tests to assist in isolating problems. Jasminum does not use clever techniques to capture or interfere with standard output and console messages. In the browser, the inspected window is left as a stage for the application under test and the test runner will only fiddle with the testing, pass, and fail classes of the body element.

In addition to describe and it, Jasmine and Jasminum both support xdescribe and xit to quickly or temporarily disable a test. In addition, Jasminum supports ddescribe and iit that will cause the test runner to focus on the annotated suites or tests.

Light

Jasminum only runs in CommonJS module loaders.

Jasminum will not include a mock clock. Please seek refuge in npm.

Jasminum does not attempt to capture errors in the “domain” of a test. Promises will usually funnel exceptions into the test scaffold, but if you throw an error from a timeout event, or any other kind of event, Jasminum will stop exactly where the problem occurred.

Jasminum does not redirect standard IO or console messages to the test reporter. Jasminum instead elects to direct its reports to the console and standard IO so that it interleaves the chronology of your program.

Jasminum only provides reporters for Node.js and console browsing.

Jasminum does not automatically run tests whenever tests or their dependencies change, but such a contraption is easy to imagine based on the dependency graph that Mr can produce.

Jasminum provides Jasmine 1.3 spies to ease migration. However, please migrate to an external spy package like Sinon for spies. Jasmine spies will be removed in a future release.

Extensible

Jasminum compensates for its minimalism with extensibility.

By way of background, the DSL provides a few extra methods. getCurrentSuite returns the suite instance for the containing describe block, both at declaration time and at test time. getCurrentTest returns the current test instances at test time, and getCurrentReport returns the current report at test time. There is no current test or report at declaration time.

Jasminum also supports corresponding set methods, but these are intended only for the use of the test runner.

Expectations

Jasminum expectations can be extended in a variety of ways.

The current suite will always have an Expectation property, that the suite will use to construct expectation instances when the test calls expect. Each nested suite, in a describe block, will have a prototypically inherited child of the parent Expectation constructor to isolate any extensions to the expectation.

The simplest is to provide overrides for existing expectation methods. Any object can implement equals or compare, which will affect the behavior of toEqual, toBeLessThan, toBeGreaterThan, toBeNear and toBeCloseTo. Look into Montage Collections for details about these generic methods.

You can create custom expectation constructors. The Jasminum Expecatation constructor provides an assert method that makes most expectations implementable with a single call to this utility method. It handles the case where the expectation has been negated and gives the reporter great flexibility in rendering the involved objects and negating the messages.

function FunnyExpectation(value, report, test) {
    Expectation.call(this, value, report, test);
    // Also sets up the .not.isNot = true, .not.not = this stuff
};

FunnyExpectation.prototype = Object.create(Expectation.prototype);
FunnyExpectation.prototype.constructor = FunnyExpectation;

FunnyExpectation.prototype.toBeFunny = function () {
    var isFunny = this.value.isFunny();
    this.assert(isFunny, ["expected", "[not] to be funny"], [this.value]);
};

Any value can implement expect(report) and return a custom expectation for that object. expect(value) will delegate to value.expect(getCurrentReport()) and return your custom expectation object. This is best illustrated by the spy and spy-expectation modules which use this facility to provide special methods for spies.

function Clown(funny, scary) {
    this.funny = funny;
    this.scary = scary;
}

Clown.prototype.expect = function (report) {
    return new FunnyExpectation(this, report);
};

Also, every suite has a specialized copy of the Expectation type from its parent suite. Methods can be added to the Expectation.prototype or the Expectation constructor can be replaced outright and the change will only apply in the current scope.

var Expectation = require("jasminum/expectation");
describe("funny objects", function () {

    getCurrentSuite().Expectation = FunnyExpecation;

    it("are funny", function () {
        expect(new ClownShoes()).toBeFunny();
        expect(new Clown()).not.toBeFunny();
    });

});

Reporter

Jasminum provides a console reporter that is suitable for tests run by Node.js, or tests run through PhantomJS and forwarded to the Node.js console. It also provides a reporter suitable for running tests in an arbitrary browser, reporting results to the browser console.

However, tests can be run with an arbitrary reporter. The Suite runAndReport and runAndReportSync methods both accept an options object which may include either a report or Reporter constructor. If neither are provided, it falls back to calling the Reporter on its prototype chain, so Suites can be extended to have an alternate default reporter. The Suite shares the run-and-report options with the reporter constructor.

The Reporter must implement:

start(test) -> reporter: returns a nested reporter instance for the given test.
end(test): concludes a test. This is a good point to check whether any assertions have failed and to calculate and propagate the test’s statistics.
skip(test): notes that the test has been skipped. end will still be called.
error(error, test): notes that an error was thrown while running the test, albeit in a promise handler. end will still be called.
assert(guard, isNot, messages, objects): reports on an assertion.

The guard may be a truthy or falsy value, but will be either exactly true or false. isNot indicates that the assertion is negative, so the guard has the opposite meaning, and if any of the messages contain the phrase " [not]", these must be replaced with " not". Otherwise, these phrases must be replaced with an empty string. The objects are intended to be interleaved after the corresponding message and there may be more messages than objects, or more objects than messages.

The Reporter may implement:

enter()
exit(exiting)

The suite runner will call enter once before running tests, and exit once after running all tests. If the tests are exiting prematurely, the exiting flag will be true, in which case, it would be innapropriate to call process.exit because doing so would prevent Node.js from printing an uncaught exception to the console.

Suite, Test

The Suite constructor can be extended. The Suite is not hard-coded to use the basic Test, Expectation, and Reporter constructors. Specialized expectations and tests can be overridden on the Suite.prototype.

Jasminum provides a reporter module with an alternate browser-reporter implementation that will be used in place of reporter automatically if it is loaded by Browserify, Mr, or Mop.

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