Run tests on PHPUnit 9, on PHP 7.4 and add .gitattributes to exclude dev files from exports

.gitattributes

@@ -0,0 +1,7 @@
+/.gitattributes export-ignore
+/.gitignore export-ignore
+/.travis.yml export-ignore
+/examples export-ignore
+/phpunit.xml export-ignore
+/phpunit-legacy.xml export-ignore
+/tests export-ignore

.travis.yml

@@ -1,34 +1,32 @@
 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
 
-matrix:
+jobs:
   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
-
-sudo: false
+    - php: hhvm-3.18
 
 addons:
   apt:
     packages:
       - graphviz
 
 install:
-  - composer install --no-interaction
+  - composer install
 
 script:
-  - vendor/bin/phpunit --coverage-text
+  - if [[ "$TRAVIS_PHP_VERSION" > "7.2" ]]; then vendor/bin/phpunit --coverage-text; fi
+  - if [[ "$TRAVIS_PHP_VERSION" < "7.3" ]]; then vendor/bin/phpunit --coverage-text -c phpunit-legacy.xml; fi

composer.json

@@ -13,6 +13,6 @@
         "graphp/graph": "dev-master#81eef65 as 1.0.0"
     },
     "require-dev": {
-        "phpunit/phpunit": "^6.4 || ^5.7 || ^4.8.35"
+        "phpunit/phpunit": "^9.3 || ^5.7 || ^4.8.35"
     }
 }

phpunit-legacy.xml

@@ -0,0 +1,18 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<!-- PHPUnit configuration file with old format for PHPUnit 9.2 or older-->
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/4.8/phpunit.xsd"
+         bootstrap="vendor/autoload.php" 
+         colors="true">
+    <testsuites>
+        <testsuite name="GraphViz Test Suite">
+            <directory>./tests/</directory>
+        </testsuite>
+    </testsuites>
+    <filter>
+        <whitelist>
+            <directory>./src</directory>
+        </whitelist>
+    </filter>
+</phpunit>

phpunit.xml

@@ -0,0 +1,19 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<!-- PHPUnit configuration file with new format for PHPUnit 9.3+ -->
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
+         xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/9.3/phpunit.xsd"
+         bootstrap="vendor/autoload.php" 
+         colors="true" 
+         cacheResult="false">
+    <testsuites>
+        <testsuite name="GraphViz Test Suite">
+            <directory>./tests/</directory>
+        </testsuite>
+    </testsuites>
+    <coverage>
+        <include>
+            <directory>./src</directory>
+        </include>
+    </coverage>
+</phpunit>

tests/GraphVizTest.php

@@ -8,7 +8,10 @@ class GraphVizTest extends TestCase
 {
     private $graphViz;
 
-    public function setUp()
+    /**
+     * @before
+     */
+    public function setUpGraphViz()
     {
         $this->graphViz = new GraphViz();
     }