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
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
|
import { backOff } from "./backoff";
import { BackoffOptions } from "./options";
describe("BackOff", () => {
const mockSuccessResponse = { success: true };
const mockFailResponse = { success: false };
let backOffRequest: () => Promise<any>;
let backOffOptions: BackoffOptions;
function initBackOff() {
return backOff(backOffRequest, backOffOptions);
}
function promiseThatIsResolved() {
return () => Promise.resolve(mockSuccessResponse);
}
function promiseThatIsRejected() {
return () => Promise.reject(mockFailResponse);
}
function promiseThatFailsOnceThenSucceeds() {
return (() => {
let firstAttempt = true;
const request = () => {
if (firstAttempt) {
firstAttempt = false;
return Promise.reject(mockFailResponse);
}
return Promise.resolve(mockSuccessResponse);
};
return request;
})();
}
beforeEach(() => {
backOffOptions = { startingDelay: 0 };
backOffRequest = jest.fn(promiseThatIsResolved());
});
describe("when request function is a promise that resolves", () => {
it("returns the resolved value", () => {
const request = initBackOff();
return request.then(response =>
expect(response).toBe(mockSuccessResponse)
);
});
it("calls the request function only once", () => {
const request = initBackOff();
return request.then(() =>
expect(backOffRequest).toHaveBeenCalledTimes(1)
);
});
it(`when the #backOffOptions.numOfAttempts is 0,
it overrides the value and calls the method only once`, () => {
backOffOptions.numOfAttempts = 0;
const request = initBackOff();
return request.then(() =>
expect(backOffRequest).toHaveBeenCalledTimes(1)
);
});
});
describe(`when the #backOffOptions.startingDelay is 100ms`, () => {
const startingDelay = 100;
beforeEach(() => (backOffOptions.startingDelay = startingDelay));
it(`does not delay the first attempt`, () => {
const startTime = Date.now();
const request = initBackOff();
return request.then(() => {
const endTime = Date.now();
const duration = endTime - startTime;
const roundedDuration = Math.round(duration / 100) * 100;
expect(roundedDuration).toBe(0);
});
});
it(`when #backOffOptions.delayFirstAttempt is 'true',
it delays the first attempt`, () => {
backOffOptions.delayFirstAttempt = true;
const startTime = Date.now();
const request = initBackOff();
return request.then(() => {
const endTime = Date.now();
const duration = endTime - startTime;
const roundedDuration = Math.round(duration / 100) * 100;
expect(roundedDuration).toBe(startingDelay);
});
});
});
describe("when request function is a promise that is rejected", () => {
beforeEach(() => (backOffRequest = promiseThatIsRejected()));
it("returns the rejected value", () => {
const request = initBackOff();
return request.catch(err => expect(err).toBe(mockFailResponse));
});
it("retries the request as many times as specified in #BackOffOptions.numOfAttempts", async () => {
const numOfAttemps = 2;
backOffOptions.numOfAttempts = numOfAttemps;
backOffRequest = jest.fn(() => Promise.reject(mockFailResponse));
try {
await initBackOff();
} catch {
expect(backOffRequest).toHaveBeenCalledTimes(numOfAttemps);
}
});
it(`when the #BackOffOptions.retry function is set to always return false,
it only calls request function one time`, async () => {
backOffOptions.retry = () => false;
backOffOptions.numOfAttempts = 2;
backOffRequest = jest.fn(() => Promise.reject(mockFailResponse));
try {
await initBackOff();
} catch {
expect(backOffRequest).toHaveBeenCalledTimes(1);
}
});
});
it("when the #BackOffOptions.retry function returns a promise, it awaits it", async () => {
const retryDuration = 100;
backOffOptions.retry = () =>
new Promise(resolve => setTimeout(() => resolve(true), retryDuration));
backOffRequest = promiseThatFailsOnceThenSucceeds();
const start = Date.now();
await initBackOff();
const end = Date.now();
const duration = end - start;
const roundedDuration =
Math.round(duration / retryDuration) * retryDuration;
expect(roundedDuration).toBe(retryDuration);
});
describe(`when calling #backOff with a function that throws an error the first time, and succeeds the second time`, () => {
beforeEach(
() => (backOffRequest = jest.fn(promiseThatFailsOnceThenSucceeds()))
);
it(`returns a successful response`, () => {
const request = initBackOff();
return request.then(response =>
expect(response).toBe(mockSuccessResponse)
);
});
it("calls the request function two times", async () => {
await initBackOff();
expect(backOffRequest).toHaveBeenCalledTimes(2);
});
it(`when setting the #BackOffOption.timeMultiple to a value,
when setting the #BackOffOption.delayFirstAttempt to true,
it applies a delay between the first and the second call`, async () => {
const startingDelay = 100;
const timeMultiple = 3;
const totalExpectedDelay = startingDelay + timeMultiple * startingDelay;
backOffOptions.startingDelay = startingDelay;
backOffOptions.timeMultiple = timeMultiple;
backOffOptions.delayFirstAttempt = true;
const start = Date.now();
await initBackOff();
const end = Date.now();
const duration = end - start;
const roundedDuration =
Math.round(duration / startingDelay) * startingDelay;
expect(roundedDuration).toBe(totalExpectedDelay);
});
});
});
|
