Run Unit Tests against PHP 7.4

Bump PHPUnit version and fix unit test

  - Globals are handled differently and are persistent through tests
  - Tests without assertions are marked as risky: some of them are just
meant to check that no error is raised.

1 files changed, 2 insertions, 0 deletions

diff --git a/.travis.yml b/.travis.yml
index d1415423..f466c317 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -4,6 +4,8 @@ dist: trusty
 matrix:
   include:
     - language: php
+      php: 7.4
+    - language: php
       php: 7.3
     - language: php
       php: 7.2