Run tests on PHP 7.4 and simplify test matrix

Author: SimonFrings

.travis.yml

@@ -1,13 +1,4 @@
 language: php
-php:
-# - 5.3 # requires old distro, see below
-  - 5.4
-  - 5.5
-  - 5.6
-  - 7.0
-  - 7.1
-  - 7.2
-  - hhvm # ignore errors, see below
 
 # lock distro so future defaults will not break the build
 dist: trusty
@@ -16,8 +7,17 @@ matrix:
   include:
     - php: 5.3
       dist: precise
+    - php: 5.4
+    - php: 5.5
+    - php: 5.6
+    - php: 7.0
+    - php: 7.1
+    - php: 7.2
+    - php: 7.3
+    - php: 7.4
+    - php: hhvm-3.18
   allow_failures:
-    - php: hhvm
+    - php: hhvm-3.18
 
 sudo: false
 

composer.json

@@ -20,6 +20,6 @@
         "react/promise": "^2.0 || ^1.0"
     },
     "require-dev": {
-        "phpunit/phpunit": "^6.0 || ^5.7 || ^4.8.35"
+        "phpunit/phpunit": "^7.0 ||^6.0 || ^5.7 || ^4.8.35"
     }
 }