throwing UnhandledPromiseRejection even the code wrapped in try catch

const express = require('express');
const app = express();
const port = 3003;

function testPromise(n) {
    return new Promise(async (res, rej) => {
        console.log(n);
        if (n > 10) {
            res(true);
        } else {
            setTimeout(() => {
                rej(n);;
            }, 1000)

        }
    });
}

function test2(n) {
    return new Promise(async (res, rej) => {
        console.log(n);
        if (n > 10) {
            res(true);
        } else {
            setTimeout(() => {
                rej(n);;
            }, 10000)

        }
    });
}
async function allCall(p) {
    await Promise.all(p);
}
app.get('/', async (req, res) => {
    try {
        let a = [];
        let b = [];

        a.push(testPromise(1));
        await test2(1);
        a.push(testPromise(12));
        // await Promise.all(a.map(m => m.then(() => { }).catch(err => { })));
        await Promise.all(a);
        res.send('Hello World!');
    } catch (err) {
        console.log('err');
        console.log(err);
        res.status(400).send('xxxxxxxxxx!')
    }

})

app.listen(port, () => {
    console.log(`Example app listening on port ${port}`)
})