I have this function and I want to test it. I want to test stream.on('error', err => reject(err)); line, but don't know how to reach it. What could I input in this function to trigger the error throw? Thank you!
function streamToString(stream) {
const chunks = [];
return new Promise((resolve, reject) => {
stream.on('data', chunk => chunks.push(Buffer.from(chunk)));
stream.on('error', err => reject(err));
stream.on('end', () => resolve(Buffer.concat(chunks).toString('utf8')));
});
}
If you are in nodejs and using jest you could Emit the error by your self like:
function streamToString(stream) {
const chunks = [];
return new Promise((resolve, reject) => {
stream.on("data", (chunk) => chunks.push(Buffer.from(chunk)));
stream.on("error", (err) => reject(err));
stream.on("end", () => resolve(Buffer.concat(chunks).toString("utf8")));
});
}
test("broken stream", () => {
let fs = require("fs");
let stream = fs.createReadStream("file.txt");
let res = streamToString(stream);
stream.emit("error", "OH NO!");
return expect(res).rejects.toMatch("OH NO!");
});
//or
test("broken stream", () => {
let fs = require("fs");
let stream = fs.createReadStream("file.txt");
let res = streamToString(stream);
stream.destroy("OH NO!");
return expect(res).rejects.toMatch("OH NO!");
});