Shouldn't this (and the one below) actually be something more like:
```
assert not np.allclose(fk5_2.ra.to(u.deg), fk5_trans.ra.to(u.deg), rtol=0, atol=1e-10)
```
That is, `allclose` isn't quantity-aware and thus just does array comparison (at least often), so it might be a false negative just because the units don't match...?

Or sometimes I do something like
```
assert not np.allclose(fk5_2 - fk5_trans.ra, 0, atol=1e-15)
```