pydata/pandas — pull request #4295 by jreback (2013-07-19 18:06:43+00:00)
Title: TST: raise an error json serialization of floats that cannot be accurate represented

related to #4042

```
In [1]: DataFrame([[1e-16,'foo',1e-8]],columns=list('ABC')).to_json()

ValueError: ujson currently cannot accurately format float data less
than 1e-15. A work-around is to multiply the data by
a large positive factor and divide on deseriliazation
```