Update test suite to support PHPUnit 9

.gitattributes

@@ -3,4 +3,5 @@
 /.gitignore export-ignore
 /bin/build.php export-ignore
 /phpunit.xml.dist export-ignore
+/phpunit.xml.legacy export-ignore
 /tests/ export-ignore

.github/workflows/ci.yml

@@ -28,6 +28,9 @@ jobs:
           coverage: xdebug
       - run: composer install
       - run: vendor/bin/phpunit --coverage-text
+        if: ${{ matrix.php >= 7.3 }}
+      - run: vendor/bin/phpunit --coverage-text -c phpunit.xml.legacy
+        if: ${{ matrix.php < 7.3 }}
       - run: composer build
 
   PHPUnit-hhvm:

composer.json

@@ -13,7 +13,7 @@
     },
     "require-dev": {
         "clue/phar-composer": "^1.3",
-        "phpunit/phpunit": "^7.5 || ^5.7 || ^4.8.36"
+        "phpunit/phpunit": "^9.5 || ^5.7 || ^4.8.36"
     },
     "autoload": {
         "psr-0": { "Clue\\GraphComposer": "src/" }

phpunit.xml.dist

@@ -1,14 +1,20 @@
 <?xml version="1.0" encoding="UTF-8"?>
 
-<phpunit colors="true" bootstrap="vendor/autoload.php">
+<!-- PHPUnit configuration file with new format for PHPUnit 9.5+ -->
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
+         xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/9.5/phpunit.xsd"
+         bootstrap="vendor/autoload.php"
+         cacheResult="false"
+         colors="true"
+         convertDeprecationsToExceptions="true">
     <testsuites>
         <testsuite name="GraphComposer Test Suite">
             <directory>./tests/</directory>
         </testsuite>
     </testsuites>
-    <filter>
-        <whitelist>
-            <directory>./src</directory>
-        </whitelist>
-    </filter>
-</phpunit>
+    <coverage>
+        <include>
+            <directory>./src/</directory>
+        </include>
+    </coverage>
+</phpunit>

phpunit.xml.legacy

@@ -0,0 +1,18 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<!-- PHPUnit configuration file with old format before PHPUnit 9 -->
+<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="GraphComposer Test Suite">
+            <directory>./tests/</directory>
+        </testsuite>
+    </testsuites>
+    <filter>
+        <whitelist>
+            <directory>./src/</directory>
+        </whitelist>
+    </filter>
+</phpunit>