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
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
|
import createEventHub from '~/helpers/event_hub_factory';
const TEST_EVENT = 'foobar';
describe('event bus factory', () => {
let eventBus;
let handler;
beforeEach(() => {
eventBus = createEventHub();
handler = jest.fn();
});
afterEach(() => {
eventBus = null;
});
describe('instance', () => {
it.each`
method
${'$on'}
${'$once'}
${'$off'}
${'$emit'}
`('has $method method', ({ method }) => {
expect(eventBus[method]).toEqual(expect.any(Function));
});
});
describe('$on', () => {
beforeEach(() => {
eventBus.$on(TEST_EVENT, handler);
});
it('calls handler when event is emitted', () => {
eventBus.$emit(TEST_EVENT);
expect(handler).toHaveBeenCalledWith();
});
it('calls handler with multiple args', () => {
eventBus.$emit(TEST_EVENT, 'arg1', 'arg2', 'arg3');
expect(handler).toHaveBeenCalledWith('arg1', 'arg2', 'arg3');
});
it('calls handler multiple times', () => {
eventBus.$emit(TEST_EVENT, 'arg1', 'arg2', 'arg3');
eventBus.$emit(TEST_EVENT, 'arg1', 'arg2', 'arg3');
expect(handler).toHaveBeenCalledTimes(2);
});
it('does not call handler after $off with handler', () => {
eventBus.$off(TEST_EVENT, handler);
eventBus.$emit(TEST_EVENT);
expect(handler).not.toHaveBeenCalled();
});
it('does not call handler after $off', () => {
eventBus.$off(TEST_EVENT);
eventBus.$emit(TEST_EVENT);
expect(handler).not.toHaveBeenCalled();
});
});
describe('$once', () => {
beforeEach(() => {
eventBus.$once(TEST_EVENT, handler);
});
it('calls handler when event is emitted', () => {
eventBus.$emit(TEST_EVENT);
expect(handler).toHaveBeenCalled();
});
it('calls the handler only once when event is emitted multiple times', () => {
eventBus.$emit(TEST_EVENT);
eventBus.$emit(TEST_EVENT);
expect(handler).toHaveBeenCalledTimes(1);
});
describe('when the handler thows an error', () => {
beforeEach(() => {
handler = jest.fn().mockImplementation(() => {
throw new Error();
});
eventBus.$once(TEST_EVENT, handler);
});
it('calls off when event is emitted', () => {
expect(() => {
eventBus.$emit(TEST_EVENT);
}).toThrow();
expect(() => {
eventBus.$emit(TEST_EVENT);
}).not.toThrow();
expect(handler).toHaveBeenCalledTimes(1);
});
});
});
});
|
