I'm using the mv module to move files, an older module that still gets a lot of downloads and has been helpful in dealing with moving files between docker volumes and also outside of docker. I created a method to treat mv method as a promise.
When unit testing, I'm struggling to mock mv when used within a method.
import mv from 'mv';
export class CmdUtils {
/**
* Move a file to a new location. Using mv, this will attempt a mv command, however
* this could fail with docker volumes and will fallback to the mv module streaming
* data to the new location as needed.
* @param filePath - Full path to file
* @param destinationFilePath - Full path to file's new destination
*/
public static moveFile = (filePath: string, destinationFilePath: string): Promise<void> => {
return new Promise((resolve, reject) => {
mv(filePath, destinationFilePath, err => {
if (!err) {
resolve();
} else {
console.error('moveFile err', err);
reject(err);
}
});
});
}
}
Here's a starting test with gaps:
import mv from 'mv';
import { CmdUtils } from './cmd-utils';
describe("CmdUtils: moveFile", () => {
it("should successfully move a file using mv module", async () => {
const sandbox = sinon.createSandbox();
try {
const moveFromPath = '/full/path/to/file.jpg';
const moveToPath = '/full/path/to/destination/file.jpg';
// Starting attempt at a replacement callback
const mvCallback = (err: Error) => {
if (!err) {
Promise.resolve();
} else {
console.error('moveFile err', err.message);
Promise.reject(err);
}
}
// Stub mv
sandbox.stub(mv)
// What am I missing here?
// Move file
await CmdUtils.moveFile(moveFromPath, moveToPath);
// expect no errors... (will revisit this)
} finally {
sandbox.restore();
}
});
});
How do I mock a successful file move? I'm seeing similar questions, yet not finding an answer just yet.
class CmdUtil {
static moveFileCb(resolve, reject, err) {
if (!err) {
resolve('RESOLVED');
} else {
reject(err);
}
}
static moveFile() {
return new Promise((resolve, reject) => {
mv('test', 'test', CmdUtil.moveFileCb.bind(this, resolve, reject))
})
}
}
then the test could be something similar to what you have where you now stub moveFileCb
. With that stub, you can check/assert what the callback was called with, how many times it was called, etc.
Side Note: I didn't write a test using bind
. That might throw a wrench into the solution.