[TESTS] Make PHPUnit exit on first fail and some other tweaks

.gitignore

@@ -59,4 +59,5 @@ config.php
 notes
 
 
-.test_coverage_report
+.test_coverage_report
+.phpunit_cache

phpunit.xml.dist

@@ -1,6 +1,14 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!-- https://phpunit.readthedocs.io/en/latest/configuration.html -->
-<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/9.3/phpunit.xsd" backupGlobals="false" colors="true" bootstrap="tests/bootstrap.php">
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/9.3/phpunit.xsd"
+         backupGlobals="false"
+         colors="true"
+         bootstrap="tests/bootstrap.php"
+         stopOnFailure="true"
+         stopOnError="true"
+         cacheResult="true"
+         cacheResultFile=".phpunit_cache">
   <coverage processUncoveredFiles="true">
     <include>
       <directory suffix=".php">src</directory>