Create test and fix for issue 427

[marcpaterno]

This closes issue #427

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 98.2%. Comparing base (a0ee415) to head (dbd5c09).
Report is 11 commits behind head on master.

Additional details and impacted files

@@          Coverage Diff           @@
##           master    #428   +/-   ##
======================================
  Coverage    98.2%   98.2%           
======================================
  Files          46      46           
  Lines        3224    3224           
======================================
  Hits         3168    3168           
  Misses         56      56           

Files with missing lines	Coverage Δ
firecrown/likelihood/two_point.py	97.5% <100.0%> (ø)