Tests for twisted.logger._json.
| Function | savedJSONInvariants | Assert a few things about the result of eventAsJSON, then 
return it. | 
| Class | SaveLoadTests | Tests for loading and saving log events. | 
| Class | FileLogObserverTests | Tests for jsonFileLogObserver. | 
| Class | LogFileReaderTests | Tests for eventsFromJSONLogFile. | 
Assert a few things about the result of eventAsJSON, then 
return it.
| Parameters | testCase | The TestCasewith 
which to perform the assertions. (type:TestCase) | 
| savedJSON | The result of eventAsJSON. (type:unicode(we 
hope)) | |
| Returns | savedJSON(type:unicode) | |
| Raises | AssertionError | If any of the preconditions fail. |