Node.js testing summary

This article is a summary of recent learning on Node.js testing, including unit testing, integration testing, benchmark testing, code coverage testing and other aspects. For medium and large projects, complete test cases help ensure the project's continuous integration capabilities and the robustness of the code.

Unit Test

Unit test, also known as module test, tests the correctness of the smallest execution unit in the program. Common development models include TDD and BDD.

  TDD (Test-driven development, test-driven development), first write test cases, and then develop modules according to the test cases. When the test cases are insufficient, add test cases; when the module fails to pass the test, continue to update the module code. Until the test case is completely passed. The core of its development revolves around test cases, that is, the completeness of test cases determines the robustness and correctness of the development module. This can easily lead to insufficient unit test coverage due to boundary conditions. H BDD (Behavior-Driven Development, behavioral driver development), semantic programming language development test cases that are close to business needs, and then drive the development of related modules.

AVA is the latest testing framework in the JavaScript ecosystem. It has built-in Babel and can directly use ES6 syntax. It has the advantages of lightweight and efficient, concurrent execution, forced isolation, etc. Installation method:

npm install --save-dev ava
Set the scripts field in package.json:

{
"scripts": { "test": "ava", "test:watch": "ava --watch"Running:

}
}

npm test
# orHere is a basic test code:

npm test:watch

import test from 'ava';
const fibonacci = (n) => { If (n === 0 || n === 1) {

           return n;
}
Return fibonacci(n - 1) + fibonacci(n - 2);
}

test('Test Fibonacci(0)', t => {
t.is(fibonacci(0), 0);
});

test('Test Fibonacci(1)', t => {
t.is(fibonacci(1), 1);
});


//HOOK CALLS

test.before('Before', t => {
console.log('before'); });
test.after('After', t => {
console.log('after');
});

test.beforeEach('BeforeEach', t => {
console.log(' beforeEach');
});

test.afterEach('AfterEach', t => {
console.log(' afterEach');
});

In the above code, we first introduced the AVA module, then created the fibonacci function to be tested, followed by two test cases, and finally four hook methods: before() / after() / beforeEach() / afterEach().

AVA provides a few modification methods to specify the execution method of the test:

1. skip(), skip test cases with skip() added;

2. only(), only execute test cases with only() added;

3. todo(), Placeholder identifier, indicating test cases that need to be added in the future;

4. serial(), executes test cases serially. By default, AVA will execute test cases in parallel.

test('Test Fibonacci(0)', t => {
t.is(fibonacci(0), 0);
});

T in the callback function of the above code is called the assertion execution object, which contains the following methods:

·t.end(), ends the test, only valid in test.cb()

·t.plan(count), specifies the number of executions

·t.pass ([message]), the test passes

·t.fail([message]), the test fails

·t.ok(value, [message]), asserts that the value of value is true Value

·t.notOK(value, [message]), asserts that the value of value is false Value

·t.true(value, [message]), asserts that the value of value is true

·t.false(value, [message]), assert that value is false

·t.is(value, expected, [message]), assert value === expected

·t.not(value, expected, [message]), assert value !== expected

·t.same(value, expected, [message]), assert value and expected The depths are equal

·t.notSame(value, expected, [message]), asserting that value and expected are not equal in depth

·t.throws(function | promise, [error, [message] ]), assert that the function throws an exception or promisereject error

·t.notThrows(function | promise, [message]), assert that the function does not throw an exception or promise resolve

·t.regex( contents, regex, [message]), asserts that contents matches regex

·t.ifError(error, [message]), asserts that error is a false value

Integration testing

Relative to unit testing that focuses on micro-modules, integration testing discovers problems from a macro-overall perspective, so it is also called assembly testing and joint testing. Travis CI is an excellent continuous integration tool that can monitor updates to Github projects and facilitate integration testing of open source software. To use Travis CI, you need to create a .travis.yml configuration file in the root directory of the project (taking Node.js as an example):

language: node_js

node_js:
- "6"
- "5"

before_script:

script:
- npm test
- node benchmark/index.js

after_script:

By default, Travis CI will automatically install dependencies and execute the npm test command. You can customize the commands that need to be executed through the script field. Its complete life cycle includes:

·Install apt addons

·before_install

·install

·before_script

·script

·after_success or after_failure

·OPTIONAL before_deploy

·OPTIONAL deploy

·OPTIONAL after_deploy

·after_ script

Benchmark Test

Benchmark test uses rigorous test methods, test tools or test systems to evaluate the performance of the target module. It is often used to observe the performance after changes in the software and hardware environment, and the results are reproducible sex. The most commonly used benchmarking tool in the Node.js environment is Benchmark.js, installation method:

npm install --save-dev benchmark

Basic example:

const Benchmark = require('benchmark');
const suite = new Benchmark.Suite;

suite.add('RegExp#test', function() {
/o/.test('Hello World!');
})
.add('String#indexOf', function() {
'Hello World!'.indexOf('o') > -1;
})
.on('cycle', function(event) {
console.log(String(event.target));
})
.on('complete', function() {
console.log('Fastest is ' + this.filter('fastest').map('name'));
})
// run async
.run({ 'async': true });

Code Coverage

The code coverage tool judges the completeness of the module based on the number of lines of code and the number of branches covered by test cases. AVA recommends using nyc to test code coverage, install nyc:

npm install nyc --save-dev

Modify .gitignore to ignore related files:

node_modules
coverage
.nyc_output

Modify the test field in package.json:

{
"scripts": {
"test": "nyc ava"
}
}

Execute npm test and get:

➜ test-in-action (master) ✔ npm test

> test-in-action@1.0.0 test /Users/sean/Desktop/test-in-action
>nyc ava

2 passed
----------|----------|----------|----------|------ ----|----------------|
File | % Stmts | % Branch | % Funcs | % Lines |Uncovered Lines |
----------|----------|----------|----------|------ ----|----------------|
----------|----------|----------|----------|------ ----|----------------|
All files | 100 | 100 | 100 | 100 | 100 |
----------|----------|----------|----------|------ ----|----------------|

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