Add PHPCompatibility to the test suite

[villfa]

Closes #315

[codecov]

Codecov Report

Merging #326 (bff645a) into master (99b6259) will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##             master     #326   +/-   ##
=========================================
  Coverage     99.06%   99.06%           
  Complexity        2        2           
=========================================
  Files            55       55           
  Lines           859      859           
=========================================
  Hits            851      851           
  Misses            8        8           

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