The uses of `t.plan`

`t.plan`

```
test(‘test it errors at some point’, (t) => {
  asyncEvent(‘data that will error’, (err, cb) => {
    if (err) {
      t.ok(err);
      t.end();
    }
    anotherAsyncEvent((err, cb) => {
      if (err) {
        t.ok(err);
        t.end();
      }
    });
  });
});
```
is not as nice as:

```
test(‘test it errors at some point’, (t) => {
  t.plan(1);
  
  asyncEvent(‘data that will error’, (err, cb) => {
    if (err) {
      t.ok(err);
    }
    anotherAsyncEvent((err, cb) => {
      if (err) {
        t.ok(err);
      }
    });
  });
});
```