-
Notifications
You must be signed in to change notification settings - Fork 406
/
17-unit-testing.html
85 lines (66 loc) · 2.74 KB
/
17-unit-testing.html
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
<!DOCTYPE html>
<title>17 Unit Testing - React From Zero</title>
<script src="https://unpkg.com/[email protected]/umd/react.development.js"></script>
<script src="https://unpkg.com/@babel/standalone/babel.min.js"></script>
<script src="https://unpkg.com/[email protected]/mocha.js">
// The basic test tool for React is Jest, but it doesn't run in the
// browser. That's why we only use parts of Jest (expect and
// jest-mock) here to illustrate basic testing setup. Mocha is used as
// an alternative test runner.
</script>
<link href="https://unpkg.com/[email protected]/mocha.css" rel="stylesheet" />
<script src="https://unpkg.com/[email protected]/umd/react-test-renderer-shallow.development.js">
// The shallow renderer is needed to render components without the
// need of ReactDOM or a DOM in general
</script>
<!-- these two libraries are parts of the Jest tooling -->
<script src="https://unpkg.com/expect@%3C21/umd/expect.min.js"></script>
<script src="https://unpkg.com/[email protected]/build-es5/index.js"></script>
<!-- the render target of the Mocha test results -->
<div id="mocha"></div>
<script type="text/babel">
// if you use Jest later, ignore Mocha specific code
mocha.setup("bdd");
// a simple component. It would normally be imported from another file
function MyComponent() {
return <div><span className="heading">Title</span></div>;
}
// the first test, Jest and Mocha both using describe() and it()
describe("Component", function() {
it("should render", function() {
// a new renderer is created and used to render the component
var renderer = new ReactShallowRenderer();
renderer.render(<MyComponent />);
// result here should look quiet familiar from lesson 00
var result = renderer.getRenderOutput();
// now you can traverse the result and check it for correctness
expect(result.type).toBe("div");
expect(result.props.children).toEqual(
<span className="heading">Title</span>
);
// Jest can also create snapshot files
// they will be used to check for changes in the next test-runs
// expect(result).toMatchSnapshot();
});
});
// it is also possible to mock parts of target code with Jest
// here we use the mock part of Jest stand-alone
// normally this is part of the global "jest" object
var jest = window["jest-mock"];
// mocking a function to test callback behaviour
var mockCallback = jest.fn();
describe("Callback", function() {
it("should be called two times", function() {
// a test function that calls a callback two times
function callCallback(c) {
c();
c();
}
callCallback(mockCallback);
// the mocked function has some properties to check its usage
expect(mockCallback.mock.calls.length).toBe(2);
});
});
mocha.checkLeaks();
mocha.run();
</script>