Running tests within a transaction

A common pattern for testing code in the Ruby world (using RSpec) is to run each of your app’s tests within a transaction, and then rollback the transaction once the test is done. That way each test is run in an isolated environment and isn’t filling up a db with junk.

Is there a way to do this with Knex? I’ve spent a few hours trying to make it work with mocha. The following don’t seem to work:

beforeEach(function (done) {
  knex.raw("start transaction").then(function () {
    done();
  });
});

afterEach(function (done) {
  knex.raw("rollback").then(function () {
    done();
  });
});

or

var trx;
beforeEach(function (done) {
  knex.transaction(function (newTrx) {
    trx = newTrx;
    done();
  });
});

afterEach(function (done) {
  trx.rollback().then(function () {
    done();
  });
});

I apologize if this question is naïve but I’m new to knex.

[JonAbrams]

Of course, the instant after I post this I figure it out. The first example I gave above worked, but I needed to set the connection’s pool to { min: 1, max: 1 } since, I assume, the transaction is only valid on one connection and therefore all queries need to go over that single connection.

[StephanHoyer]

@JonAbrams you have to take care that all queries that are executed during the test are run within this transaction.

describe('stuff', () => {
  var trx = knex;
  beforeEach(function (done) {
    knex.transaction(function (newTrx) {
      trx = newTrx;
      done();
    });
  });

  it('should work', function () {
    return trx('table_name').insert(data);
  });
});