MAINT: Extra test for annotations

[larsoner]

It occurred to me that it might be nice to have a specific regression test for #5908.

@massich might be good to have while working on #5857

[codecov]

Codecov Report

Merging #6313 into master will increase coverage by 0.2%.
The diff coverage is 100%.

@@            Coverage Diff            @@
##           master    #6313     +/-   ##
=========================================
+ Coverage   89.18%   89.39%   +0.2%     
=========================================
  Files         417      417             
  Lines       75158    75960    +802     
  Branches    12375    12727    +352     
=========================================
+ Hits        67033    67906    +873     
+ Misses       5240     5192     -48     
+ Partials     2885     2862     -23

[massich]

This already works with v0.16, so I don't really understand what was not working with #5908

Python 3.6.8 |Anaconda, Inc.| (default, Dec 30 2018, 01:22:34) 
Type 'copyright', 'credits' or 'license' for more information
IPython 7.4.0 -- An enhanced Interactive Python. Type '?' for help.

In [1]: import mne                                                                               

In [2]: mne.__version__                                                                          
Out[2]: '0.16.0'

In [3]: import os.path as op 
   ...:  
   ...: import numpy as np 
   ...:  
   ...: from mne import create_info 
   ...: from mne.io import read_raw_fif, RawArray 
   ...:  
   ...:  
   ...: tmpdir = '/tmp/' 
   ...:  
   ...: # def test_date_none(tmpdir): 
   ...: """Test that DATE_NONE is used properly.""" 
   ...: # Regression test for gh-5908 
   ...: n_chans = 139 
   ...: n_samps = 20 
   ...: data = np.random.random_sample((n_chans, n_samps)) 
   ...: ch_names = ['E{}'.format(x) for x in range(n_chans)] 
   ...: ch_types = ['eeg'] * n_chans 
   ...: info = create_info(ch_names=ch_names, ch_types=ch_types, sfreq=2048) 
   ...: assert info['meas_date'] is None 
   ...: raw = RawArray(data=data, info=info) 
   ...: fname = op.join(str(tmpdir), 'test-raw.fif') 
   ...: raw.save(fname) 
   ...: raw_read = read_raw_fif(fname, preload=True) 
   ...: assert raw_read.info['meas_date'] is None 
   ...:                                                                                          

In [4]:                                                                                          

But I'm +1 to add it