I use the simple-git package. I have the following function:
import simpleGit from 'simple-git';
/**
* The function returns the ticket Id, is presents, in the branch name
* @returns ticket Id
*/
export const getTicketIdFromBranchName = async (ticketRegex: RegExp) => {
const git = simpleGit();
try {
const localBranches = await git.branchLocal();
const currentBranch = localBranches.current;
const currentBranchTicketMatches = currentBranch.match(ticketRegex);
if (currentBranchTicketMatches) {
return currentBranchTicketMatches[0];
}
return null;
} catch {
return null;
}
};
I try to create a unit-test for this function:
import { getTicketIdFromBranchName } from '@/utils/git-info';
const TICKET_ID_REGEX = /((?<!([A-Z]{1,10})-?)[A-Z]+-\d+)/.source;
describe('[utils/git-info]', () => {
it('getTicketIdFromBranchName | Function should proper ticket Id when there is one', async () => {
const ticketId = 'CLO-1234';
jest.mock('simple-git', () => {
const mGit = {
branchLocal: jest.fn(() => Promise.resolve({ current: `${ticketId} DUMMY TEST` })),
};
return jest.fn(() => mGit);
});
const result = await getTicketIdFromBranchName(new RegExp(TICKET_ID_REGEX));
expect(result === ticketId).toEqual(true);
});
});
But the unit-test fails. I says I expected to get true but it got false in the final line.
I guess I use jest.mock in the wrong way.
The official documentation has a key description of the use of jest.mock.
Note: In order to mock properly, Jest needs
jest.mock('moduleName')to be in the same scope as therequire/importstatement.
You call the jest.mock('moduleName') inside test case function scope, but import the git-info module in module scope. That's why mock doesn't work.
Use require('moduleName') or await import('moduleName') in test case function. The order of the require/import and jest.mock() statements does not matter.
git-info.js:
import simpleGit from 'simple-git';
/**
* The function returns the ticket Id, is presents, in the branch name
* @returns ticket Id
*/
export const getTicketIdFromBranchName = async (ticketRegex) => {
const git = simpleGit();
try {
const localBranches = await git.branchLocal();
const currentBranch = localBranches.current;
const currentBranchTicketMatches = currentBranch.match(ticketRegex);
if (currentBranchTicketMatches) {
return currentBranchTicketMatches[0];
}
return null;
} catch {
return null;
}
};
git-info.test.js:
const TICKET_ID_REGEX = /((?<!([A-Z]{1,10})-?)[A-Z]+-\d+)/.source;
describe('[utils/git-info]', () => {
it('getTicketIdFromBranchName | Function should proper ticket Id when there is one', async () => {
const { getTicketIdFromBranchName } = await import('./git-info');
const ticketId = 'CLO-1234';
jest.mock(
'simple-git',
() => {
const mGit = {
branchLocal: jest.fn(() => Promise.resolve({ current: `${ticketId} DUMMY TEST` })),
};
return jest.fn(() => mGit);
},
{ virtual: true }
);
const result = await getTicketIdFromBranchName(new RegExp(TICKET_ID_REGEX));
expect(result === ticketId).toEqual(true);
});
});
Test result:
PASS stackoverflow/71808909/git-info.test.js (7.439 s)
[utils/git-info]
✓ getTicketIdFromBranchName | Function should proper ticket Id when there is one (6892 ms)
-------------|---------|----------|---------|---------|-------------------
File | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s
-------------|---------|----------|---------|---------|-------------------
All files | 84.62 | 50 | 100 | 81.82 |
git-info.js | 84.62 | 50 | 100 | 81.82 | 19-21
-------------|---------|----------|---------|---------|-------------------
Test Suites: 1 passed, 1 total
Tests: 1 passed, 1 total
Snapshots: 0 total
Time: 8.215 s, estimated 9 s
package version: "jest": "^26.6.3"