Merge pull request #1

* pr-1:
  Refactor unit tests.
  Refactor to be compatible with PHPUnit 8
  Add .phpunit.result.cache to .gitignore
  Update dependencies.
  remove deprecated classes

Author: TiSiE

.gitignore

@@ -7,6 +7,9 @@ vendor
 # ignore test/coverage reports
 test/coverage
 
+# ignore phpunit cache
+.phpunit.result.cache
+
 # Ignore IDEs
 .idea
 .atom

composer.json

@@ -14,8 +14,8 @@
     "optimize-autoloader": false
   },
   "require": {
-    "php": ">=7.1",
-    "phpunit/phpunit": "^5.7"
+    "php": ">=7.2",
+    "phpunit/phpunit": "^8.0"
   },
   "autoload": {
     "psr-4": {