In my React component I have some no-op functions, which basically is just placeholders for a functions. I have Istanbul test coverage, and it's complain on no-op function coverage:
Is there any ways to cover it?
To make Instanbul ignore noop functions we can use /* istanbul ignore next */ mentioned here.
For you example coverage, you could do something like
const defaultContext = {
activeInput: null,
removeFocus: /* istanbul ignore next */ () => {},
focusInput: /* istanbul ignore next */ () => {},
}
Or you could define an isolated noop function and reuse whenever needs
/* istanbul ignore next */
function noop() {}
const defaultContext = {
activeInput: null,
removeFocus: noop,
focusInput: noop,
}
Related
How can we do callback on success and failue cases for below lines of code for test coverage using jest
const handleService = () => {
window.domain.service("1321",'',onSuccess, onFailure)
}
const onSuccess = () => {
....update state values
}
const onFailure = () => {
....update state values
}
Something like this:
Spy on window.domain.service to gain access to the calls it receives. This will allow you to access the parameters of those calls which will be "1321",'',onSuccess, onFailure
Assign the function you wish to test to a variable
Invoke the function to execute the code in it (this will get you the coverage)
(Optional) assert that the callback functions behave correctly
Here is a snippet to help demonstrate
it('should run', () => {
// Some setup to create the function on the window, may not be needed if done elsewhere.
// Could be good to do this in a beforeEach and clean up in afterEach to avoid contaminating the window object
window.domain = {
service: () => {},
}
// Spy on the window.domain.service method.
// Provide a mock implementation if you don't want the real one to be called
const serviceSpy = jest.spyOn(window.domain, 'service');
executeYourCode();
// capture the arguments to the call
const [_arg1, _arg2, onSuccess, onFailure] = serviceSpy.mock.calls[0];
// execute the callbacks
onSuccess();
onFailure();
});
I try to call a lot of async functions in my mocha JS before hook but they are executed at last. Basically I am trying to execute repeated tests with different params from the constructor initialization.
I tried with only one function but it also execute at last.Tried to pass done() function to inner async function but it doesnt help either.
a.test.js and base.tests.js files :
describe('Test block', () => {
before((done) => {
const baseClass = new baseClass()
baseTests.applyTests(done)
});
describe('test',()=>{
....first which should be executed;
})
}
----------------------------------------------------------------
class baseClass {
constructor() {
init smth....
}
async applyTests(done) {
await Promise.All(
[
a(),
b(),
c()
]
done();
)
}
async a() {
return describe('TEST', () => {
it('TEST', (done) => {
chai.request(server)
.get(url)
.end((err, res) => {
asserts...
done();
});
});
}}
I expect to run first the async operations in the before hook and after that all other tests.
Keep in mind that describe and it blocks do not execute any tests; they add tests to the test list that Mocha will execute. Putting a describe block inside a function called from a before hook like this won't ever end up executing code like chai.request(... etc. (And even if it did, it would be totally broken: a before hook is run before each test, you don't want to do asserts there because it won't be linked to any particular unit test.)
I can't give more concrete advice because I'm not sure what you were trying to accomplish, but in general, your describe and it blocks should be top-level constructs and not put inside other code like this.
EDIT: Just to make the execution path here clear: your before hook runs, which calls applyTests, which calls a(), which executes a describe block and adds your unit test TEST to the test list, then it returns. It then begins running tests, including test and TEST.
EDIT: Ah, makes sense, let me suggest two patterns that are often used in unit tests.
Pattern 1: "Test Loop"
This pattern creates many similar-looking tests, using an array of input params to produce appropriate test descriptions and test bodies.
[
{ foo: "milk", bar: "smoothie" },
{ foo: "yogurt", bar: "fridge" },
{ foo: "whatever", bar: "container" }
].forEach(test => {
it("puts the " + test.foo + " in the " + test.bar, function () {
assert(subject.someMethod(foo) === bar);
});
});
Pattern 2: "Test Helper"
This pattern creates individual tests, but puts a common test body in a helper method so it can be reused.
function testSomeMethod(foo, bar) {
assert(subject(foo) == "bar");
}
it("puts the milk in the fridge", function () {
testSomeMethod("milk", "fridge");
});
it("puts the cereal in the pantry", function () {
testSomeMethod("cereal", "pantry");
});
Examples above are very simple, but either the test loop or the test helper pattern can be used to encapsulate a much more complicated series of steps (set up a request, look at some response headers / bodies, etc.).
I'm having some issues using sinon stubs and it may stem from how I'm implementing namespacing on the module that I'm looking to stub. Methods directly defined on the prototype are stubbed as I would expect.
...my module.js
const Constructor = require('./constructor') //...just exports a singleton
/* Need to namespace some of my functions and retain the `this` context */
Object.defineProperty(Constructor.prototype, 'es', {
get: function() {
return {
method: require('./implementations/doesSomething.js').bind(this)
}
}
});
module.exports = Constructor;
/* ...testFile.js */
const Constructor = require('./constructor');
const instance = new Constructor();
const sinon = require('sinon');
sinon.stub(instance.es, 'method', function() {
return 'hijacked original method'
});
As mentioned on the Sinon issue tracker, the problem here is that using a plain Object.defineProperty(obj, 'prop') call does something else than plainly creating it using assignment (obj['prop'] = ...).
Generally, if you try defining your property without Object.defineProperty it will be stubbable, but using defineProperty (without creating a special configuration) will make it impossible to stub the property. The reason is simply that the default values for writeable and configurable are false! You cannot delete them or change them. And if you can't do that, then Sinon won't help you. So, generally, you need to add writeable: true, configurable: true in your property definition.
Now there was one more thing I forgot to answer originally:
You are not trying to wrap a function on Constructor.prototype.es.method - what you are trying to wrap is the function on the object returned by the getter on the property for es. That will never work. Why? Simply because the returned object is never the same. You are creating a new object around method each time. If you really need to replace/stub the method property, you actually need to replace the entire Constructor.prototype.es property instead. If you need this namespacing, you can vastly simplify this, and also enable stubbing, like this:
Constructor.prototype.es = {};
Object.defineProperty(Constructor.prototype.es, 'method', {
get: function() {
return someFunction.bind(this);
},
writeable: true,
configurable:true
}
An expanded, fully working example (Gist for download):
// constructor.js
const someFunction = function(){
return this.value;
}
function Constructor(){ };
Constructor.prototype.es = { value : 100 };
Object.defineProperty(Constructor.prototype.es, 'method', {
get: function() {
return someFunction.bind(this);
},
writeable: true,
configurable:true
});
// test.js
const instance = new Constructor();
console.log(instance.es.method()) // => 100
// using this won't work:
// sinon.stub(instance.__proto__.es, 'method').returns(42);
// because the getter is returning a _new_ function each time
// therefore you need to attack the actual getter function:
const stub = sinon.stub(instance.__proto__.es, 'method').value(()=>42);
console.log(instance.es.method()) // => 42
stub.get(()=>()=>84);
console.log(instance.es.method()) // => 84
stub.restore();
console.log(instance.es.method()) // => 100
// the above is working on the prototype, can't we do this on the instance?
// yes, we can, but remember that the `es` object is shared, so we
// can avoid modifying it by shadowing it further down the prototype
instance.es = { method: sinon.stub().returns(256) };
console.log(instance.es.method()) // => 256
delete instance.es
console.log(instance.es.method()) // => 100
<script src="https://unpkg.com/sinon#2.3.5/pkg/sinon.js"></script>
I'm trying to create mocha tests for my controllers using a config that has to be loaded async. Below is my code. However, when the mocha test is run, it doesn't run any tests, displaying 0 passing. The console.logs are never even called. I tried doing before(next => config.build().then(next)) inside of the describe, but even though the tests run, before is never called. Is there a way to have the config be loaded one time before any tests are run?
'use strict';
const common = require('./common');
const config = require('../config');
config
.build()
.then(test);
function test() {
console.log(1);
describe('Unit Testing', () => {
console.log(2);
require('./auth');
});
}
You should run Mocha with the --delay option, and then use run() once you are done building your test suite. Here is an example derived from the code you show in the question:
'use strict';
function test() {
console.log(1);
describe('Unit Testing', () => {
console.log(2);
it("test", () => {
console.log(3);
});
});
// You must use --delay for `run()` to be available to you.
run();
}
setTimeout(test, 1000);
I'm using setTimeout to simulate an asynchronous operation. Using --delay and run() allows you to build a suite that is the result of an asynchronous computation. Note, however, that the suite must be built in one shot. (You cannot have an asynchronous process inside describe that will make calls to it. This won't work.)
One thing you should definitely not do is what rob3c suggests: calling describe or it (or both) from inside a hook. This is a mistake that every now and then people make so it is worth addressing in details. The problem is that it is just not supported by Mocha, and therefore there are no established semantics associated with calling describe or it from inside a hook. Oh, it is possible to write simple examples that work as one might expect but:
When the suite becomes more complex, the suite's behavior no longer corresponds to anything sensible.
Since there are no semantics associated with this approach, newer Mocha releases may handle the erroneous usage differently and break your suite.
Consider this simple example:
const assert = require("assert");
const p = Promise.resolve(["foo", "bar", "baz"]);
describe("top", () => {
let flag;
before(() => {
flag = true;
return p.then((names) => {
describe("embedded", () => {
for (const name of names) {
it(name, () => {
assert(flag);
});
}
});
});
});
after(() => {
flag = false;
});
it("regular test", () => {
assert(flag);
});
});
When we run it, we get:
top
✓ regular test
embedded
1) foo
2) bar
3) baz
1 passing (32ms)
3 failing
// [stack traces omitted for brevity]
What's going on here? Shouldn't all the tests pass? We set flag to true in the before hook for the top describe. All tests we create in it should see flag as true, no? The clue is in the output above: when we create tests inside a hook, Mocha will put the tests somewhere but it may not be in a location that reflects the structure of the describe blocks in the code. What happens in this case is that Mocha just appends the tests created in the hook the the very end of the suite, outside the top describe, so the after hook runs before the dynamically created tests, and we get a counter-intuitive result.
Using --delay and run(), we can write a suite that behaves in a way concordant with intuition:
const assert = require("assert");
const p = Promise.resolve(["foo", "bar", "baz"]).then((names) => {
describe("top", () => {
let flag;
before(() => {
flag = true;
});
after(() => {
flag = false;
});
describe("embedded", () => {
for (const name of names) {
it(name, () => {
assert(flag);
});
}
});
it("regular test", () => {
assert(flag);
});
});
run();
});
Output:
top
✓ regular test
embedded
✓ foo
✓ bar
✓ baz
4 passing (19ms)
In modern environments, you can use top-level await to fetch your data up front. This is a documented approach for mocha: https://mochajs.org/#dynamically-generating-tests
Slightly adapting the example from the mocha docs to show the general idea:
function fetchData() {
return new Promise((resolve) => setTimeout(resolve, 5000, [1, 2, 3]));
}
// top-level await: Node >= v14.8.0 with ESM test file
const data = await fetchData();
describe("dynamic tests", function () {
data.forEach((value) => {
it(`can use async data: ${value}`, function () {
// do something with data here
});
});
});
This is nice as it is on a per-file basis, and doesn't involve you taking on management responsibility of the test runner as you do with --delay.
The problem with using the --delay command line flag and run() callback that #Louis mentioned in his accepted answer, is that run() is a single global hook that delays the root test suite. Therefore, you have to build them all at once (as he mentioned), which can make organizing tests a hassle (to say the least).
However, I prefer to avoid magic flags whenever possible, and I certainly don't want to have to manage my entire test suite in a single global run() callback. Fortunately, there's a way to dynamically create the tests on a per-file basis, and it doesn't require any special flags, either :-)
To dynamically create It() tests in any test source file using data obtained asynchronously, you can (ab)use the before() hook with a placeholder It() test to ensure mocha waits until before() is run. Here's the example from my answer to a related question, for convenience:
before(function () {
console.log('Let the abuse begin...');
return promiseFn().
then(function (testSuite) {
describe('here are some dynamic It() tests', function () {
testSuite.specs.forEach(function (spec) {
it(spec.description, function () {
var actualResult = runMyTest(spec);
assert.equal(actualResult, spec.expectedResult);
});
});
});
});
});
it('This is a required placeholder to allow before() to work', function () {
console.log('Mocha should not require this hack IMHO');
});
Preparation
Hi i am using CasperJS in combination with grunt-casper (github.com/iamchrismiller/grunt-casper) for running automated functional and regression tests in our GUI Development process for verification.
We use it like this, casper runner in gruntfile.js:
casper: {
componentTests: {
options: {
args: ['--ssl-protocol=any', '--ignore-ssl-errors=true', '--web-security=no'],
test: true,
includes: ['tests/testutils/testutils.js']
},
files: {
'tests/testruns/logfiles/<%= grunt.template.today("yyyy-mm-dd-hhMMss") %>/componenttests/concat-testresults.xml': [
'tests/functionaltests/componenttests/componentTestController.js']
}
},
so as it can be seen here we just normally run casper tests with SSL params and calling only ONE Controllerclass here instead of listing the single tests (this is one of the roots of my problem). grunt-casper delivers the object which is in charge for testing and inside every single Controllerclass the tests are included and concatenated....
...now the componentTestController.js looks like the following:
var config = require('../../../testconfiguration');
var urls = config.test_styleguide_components.urls;
var viewportSizes = config.test_styleguide_components.viewportSizes;
var testfiles = config.test_styleguide_components.testfiles;
var tempCaptureFolder = 'tests/testruns/temprun/';
var testutils = new testutils();
var x = require('casper').selectXPath;
casper.test.begin('COMPONENT TEST CONTROLLER', function(test) {
casper.start();
/* Run tests for all given URLs */
casper.each(urls, function(self, url, i) {
casper.thenOpen(url, function() {
/* Test different viewport resolutions for every URL */
casper.each(viewportSizes, function(self, actViewport, j) {
/* Reset the viewport */
casper.then(function() {
casper.viewport(actViewport[0], actViewport[1]);
});
/* Run the respective tests */
casper.then(function() {
/* Single tests for every resolution and link */
casper.each(testfiles, function(self, actTest, k) {
casper.then(function() {
require('.'+actTest);
});
});
});
});
});
});
casper.run(function() {
test.done();
});
});
Here you can see that we running a 3 level loop for testing
ALL URLs given in a JSON config file which are contained in an ARRAY of String ["url1.com","url2.com"....."urln.com"]
ALL VIEWPORT SIZES so that every URL is tested in our desired Viewport resolutions to test the correct Responsibility behaviour of the components
ALL TESTFILES, all testfiles only include a TEST STUB what means, no start, begin or something else, its all in a large Testsourrounding.
MAYBE this is already mocky and can be done in a bette way, so if this is the case i would glad if someone has proposals here, but don't forget that grunt-casper is involved as runner.
Question
So far, so good, the tool in general works fine and the construction we built works as we desired. But the problem is, because all testfiles are ran in a large single context, one failing component fails the whole suite.
In normal cases this is a behaviour i would support, but in our circumstances i do not see any proper solution than log the error / fail the single testcomponent and run on.
Example:
I run a test, which is setUp like described above and in this part:
/* Single tests for every resolution and link */
casper.each(testfiles, function(self, actTest, k) {
casper.then(function() {
require('.'+actTest);
});
});
we include 2 testfiles looking like the following:
Included testfile1.js
casper.then(function () {
casper.waitForSelector(x("//a[normalize-space(text())='Atoms']"),
function success() {
casper.test.assertExists(x("//a[normalize-space(text())='Atoms']"));
casper.click(x("//a[normalize-space(text())='Atoms']"));
},
function fail() {
casper.test.assertExists(x("//a[normalize-space(text())='Atoms']"));
});
});
Included testfile2.js
casper.then(function () {
casper.waitForSelector(x("//a[normalize-space(text())='Buttons']"),
function success() {
casper.test.assertExists(x("//a[normalize-space(text())='Buttons']"));
casper.click(x("//a[normalize-space(text())='Buttons']"));
},
function fail() {
testutils.createErrorScreenshot('#menu > li.active > ul > li:nth-child(7)', tempCaptureFolder, casper, 'BUTTONGROUPS#2-buttons-menu-does-not-exist.png');
casper.test.assertExists(x("//a[normalize-space(text())='Buttons']"));
});
});
So if the assert in testfile1.js fails, everthing failes. So how can i move on to testfile2.js, even if the first fails? Is this possible to configure? Can it be encapsulated somehow?
FYI, this did not work:
https://groups.google.com/d/msg/casperjs/3jlBIx96Tb8/RRPA9X8v6w4J
Almost similar problems
My problem is almost the same like this here:
https://stackoverflow.com/a/27755205/4353553
And this guy here has almost another approach i tried but got his problems too because multiple testsuites ran in a loop occuring problems:
groups.google.com/forum/#!topic/casperjs/VrtkdGQl3FA
MUCH THANKS IN ADVICE
Hopefully I understood what you ware asking - is there a way to suppress the failed assertion's exception throwing behavior?
The Tester's assert method actually allows for overriding the default behavior of throwing an exception on a failed assertion:
var message = "This test will always fail, but never throw an exception and fail the whole suite.";
test.assert(false, message, { doThrow: false });
Not all assert helpers have this option though and the only other solution I can think of is catching the exception:
var message = "This test will always fail, but never throw an exception and fail the whole suite.";
try {
test.assertEquals(true, false, message);
} catch (e) { /* Ignore thrown exception. */ }
Both of these approaches are far from ideal since the requirement in our cases is to not throw for all assertions.
Another short term solution that requires overriding the Tester instance's core assert method is (but is still quite hacky):
// Override the default assert method. Hopefully the test
// casper property doesn't change between running suites.
casper.test.assert =
casper.test.assertTrue = (function () {
// Save original assert.
var __assert = casper.test.assert;
return function (subject, message, context) {
casper.log('Custom assert called!', 'debug');
try {
return __assert.apply(casper.test, arguments);
}
catch (error) {
casper.test.processAssertionResult(error.result);
return false;
}
};
})();
That said, I'm currently looking for a non-intrusive solution to this "issue" (not being able to set a default value for doThrow) as well. The above is relative to Casper JS 1.1-beta3 which I'm currently using.