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
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
|
---
stage: none
group: Development
info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/product/ux/technical-writing/#assignments
---
# Writing consumer tests
This tutorial guides you through writing a consumer test from scratch. To start, the consumer tests are written using [`jest-pact`](https://github.com/pact-foundation/jest-pact) that builds on top of [`pact-js`](https://github.com/pact-foundation/pact-js). This tutorial shows you how to write a consumer test for the `/discussions.json` REST API endpoint, which is `/:namespace_name/:project_name/-/merge_requests/:id/discussions.json`, that is called in the `MergeRequests#show` page. For an example of a GraphQL consumer test, see [`spec/contracts/consumer/specs/project/pipelines/show.spec.js`](https://gitlab.com/gitlab-org/gitlab/-/tree/master/spec/contracts/consumer/specs/project/pipelines/show.spec.js).
## Create the skeleton
Start by creating the skeleton of a consumer test. Since this is for a request in the `MergeRequests#show` page, under `spec/contracts/consumer/specs/project/merge_requests`, create a file called `show.spec.js`.
Then, populate it with the following function and parameters:
- [`pactWith`](#the-pactwith-function)
- [`PactOptions`](#the-pactoptions-parameter)
- [`PactFn`](#the-pactfn-parameter)
For more information about how the contract test directory is structured, see [Test suite folder structure](index.md#test-suite-folder-structure).
### The `pactWith` function
The Pact consumer test is defined through the `pactWith` function that takes `PactOptions` and the `PactFn`.
```javascript
import { pactWith } from 'jest-pact';
pactWith(PactOptions, PactFn);
```
### The `PactOptions` parameter
`PactOptions` with `jest-pact` introduces [additional options](https://github.com/pact-foundation/jest-pact/blob/dce370c1ab4b7cb5dff12c4b62246dc229c53d0e/README.md#defaults) that build on top of the ones [provided in `pact-js`](https://github.com/pact-foundation/pact-js#constructor). In most cases, you define the `consumer`, `provider`, `log`, and `dir` options for these tests.
```javascript
import { pactWith } from 'jest-pact';
pactWith(
{
consumer: 'MergeRequests#show',
provider: 'GET discussions',
log: '../logs/consumer.log',
dir: '../contracts/project/merge_requests/show',
},
PactFn
);
```
For more information about how to name consumers and providers, see [Naming conventions](index.md#naming-conventions).
### The `PactFn` parameter
The `PactFn` is where your tests are defined. This is where you set up the mock provider and where you can use the standard Jest methods like [`Jest.describe`](https://jestjs.io/docs/api#describename-fn), [`Jest.beforeEach`](https://jestjs.io/docs/api#beforeeachfn-timeout), and [`Jest.it`](https://jestjs.io/docs/api#testname-fn-timeout). For more information, see [https://jestjs.io/docs/api](https://jestjs.io/docs/api).
```javascript
import { pactWith } from 'jest-pact';
pactWith(
{
consumer: 'MergeRequests#show',
provider: 'GET discussions',
log: '../logs/consumer.log',
dir: '../contracts/project/merge_requests/show',
},
(provider) => {
describe('GET discussions', () => {
beforeEach(() => {
});
it('return a successful body', async () => {
});
});
},
);
```
## Set up the mock provider
Before you run your test, set up the mock provider that handles the specified requests and returns a specified response. To do that, define the state and the expected request and response in an [`Interaction`](https://github.com/pact-foundation/pact-js/blob/master/src/dsl/interaction.ts).
For this tutorial, define four attributes for the `Interaction`:
1. `state`: A description of what the prerequisite state is before the request is made.
1. `uponReceiving`: A description of what kind of request this `Interaction` is handling.
1. `withRequest`: Where you define the request specifications. It contains the request `method`, `path`, and any `headers`, `body`, or `query`.
1. `willRespondWith`: Where you define the expected response. It contains the response `status`, `headers`, and `body`.
After you define the `Interaction`, add that interaction to the mock provider by calling `addInteraction`.
```javascript
import { pactWith } from 'jest-pact';
import { Matchers } from '@pact-foundation/pact';
pactWith(
{
consumer: 'MergeRequests#show',
provider: 'GET discussions',
log: '../logs/consumer.log',
dir: '../contracts/project/merge_requests/show',
},
(provider) => {
describe('GET discussions', () => {
beforeEach(() => {
const interaction = {
state: 'a merge request with discussions exists',
uponReceiving: 'a request for discussions',
withRequest: {
method: 'GET',
path: '/gitlab-org/gitlab-qa/-/merge_requests/1/discussions.json',
headers: {
Accept: '*/*',
},
},
willRespondWith: {
status: 200,
headers: {
'Content-Type': 'application/json; charset=utf-8',
},
body: Matchers.eachLike({
id: Matchers.string('fd73763cbcbf7b29eb8765d969a38f7d735e222a'),
project_id: Matchers.integer(6954442),
...
resolved: Matchers.boolean(true)
}),
},
};
provider.addInteraction(interaction);
});
it('return a successful body', async () => {
});
});
},
);
```
### Response body `Matchers`
Notice how we use `Matchers` in the `body` of the expected response. This allows us to be flexible enough to accept different values but still be strict enough to distinguish between valid and invalid values. We must ensure that we have a tight definition that is neither too strict nor too lax. Read more about the [different types of `Matchers`](https://github.com/pact-foundation/pact-js/blob/master/docs/matching.md). We are currently using the V2 matching rules.
## Write the test
After the mock provider is set up, you can write the test. For this test, you make a request and expect a particular response.
First, set up the client that makes the API request. To do that, create `spec/contracts/consumer/resources/api/project/merge_requests.js` and add the following API request. If the endpoint is a GraphQL, then we create it under `spec/contracts/consumer/resources/graphql` instead.
```javascript
import axios from 'axios';
export async function getDiscussions(endpoint) {
const { url } = endpoint;
return axios({
method: 'GET',
baseURL: url,
url: '/gitlab-org/gitlab-qa/-/merge_requests/1/discussions.json',
headers: { Accept: '*/*' },
})
}
```
After that's set up, import it to the test file and call it to make the request. Then, you can make the request and define your expectations.
```javascript
import { pactWith } from 'jest-pact';
import { Matchers } from '@pact-foundation/pact';
import { getDiscussions } from '../../../resources/api/project/merge_requests';
pactWith(
{
consumer: 'MergeRequests#show',
provider: 'GET discussions',
log: '../logs/consumer.log',
dir: '../contracts/project/merge_requests/show',
},
(provider) => {
describe('GET discussions', () => {
beforeEach(() => {
const interaction = {
state: 'a merge request with discussions exists',
uponReceiving: 'a request for discussions',
withRequest: {
method: 'GET',
path: '/gitlab-org/gitlab-qa/-/merge_requests/1/discussions.json',
headers: {
Accept: '*/*',
},
},
willRespondWith: {
status: 200,
headers: {
'Content-Type': 'application/json; charset=utf-8',
},
body: Matchers.eachLike({
id: Matchers.string('fd73763cbcbf7b29eb8765d969a38f7d735e222a'),
project_id: Matchers.integer(6954442),
...
resolved: Matchers.boolean(true)
}),
},
};
});
it('return a successful body', async () => {
const discussions = await getDiscussions({
url: provider.mockService.baseUrl,
});
expect(discussions).toEqual(Matchers.eachLike({
id: 'fd73763cbcbf7b29eb8765d969a38f7d735e222a',
project_id: 6954442,
...
resolved: true
}));
});
});
},
);
```
There we have it! The consumer test is now set up. You can now try [running this test](index.md#run-the-consumer-tests).
## Improve test readability
As you may have noticed, the request and response definitions can get large. This results in the test being difficult to read, with a lot of scrolling to find what you want. You can make the test easier to read by extracting these out to a `fixture`.
Create a file under `spec/contracts/consumer/fixtures/project/merge_requests` called `discussions.fixture.js` where you will place the `request` and `response` definitions.
```javascript
import { Matchers } from '@pact-foundation/pact';
const body = Matchers.eachLike({
id: Matchers.string('fd73763cbcbf7b29eb8765d969a38f7d735e222a'),
project_id: Matchers.integer(6954442),
...
resolved: Matchers.boolean(true)
});
const Discussions = {
body: Matchers.extractPayload(body),
success: {
status: 200,
headers: {
'Content-Type': 'application/json; charset=utf-8',
},
body,
},
scenario: {
state: 'a merge request with discussions exists',
uponReceiving: 'a request for discussions',
},
request: {
withRequest: {
method: 'GET',
path: '/gitlab-org/gitlab-qa/-/merge_requests/1/discussions.json',
headers: {
Accept: '*/*',
},
},
},
};
exports.Discussions = Discussions;
```
With all of that moved to the `fixture`, you can simplify the test to the following:
```javascript
import { pactWith } from 'jest-pact';
import { Discussions } from '../../../fixtures/project/merge_requests/discussions.fixture';
import { getDiscussions } from '../../../resources/api/project/merge_requests';
const CONSUMER_NAME = 'MergeRequests#show';
const PROVIDER_NAME = 'GET discussions';
const CONSUMER_LOG = '../logs/consumer.log';
const CONTRACT_DIR = '../contracts/project/merge_requests/show';
pactWith(
{
consumer: CONSUMER_NAME,
provider: PROVIDER_NAME,
log: CONSUMER_LOG,
dir: CONTRACT_DIR,
},
(provider) => {
describe(PROVIDER_NAME, () => {
beforeEach(() => {
const interaction = {
...Discussions.scenario,
...Discussions.request,
willRespondWith: Discussions.success,
};
provider.addInteraction(interaction);
});
it('return a successful body', async () => {
const discussions = await getDiscussions({
url: provider.mockService.baseUrl,
});
expect(discussions).toEqual(Discussions.body);
});
});
},
);
```
|