diff --git a/phpunit.xml b/phpunit.xml
index 03fcbf718f..b083450096 100644
--- a/phpunit.xml
+++ b/phpunit.xml
@@ -4,8 +4,10 @@
 	bootstrap="tests/bootstrap.php"
 	cacheResult="false"
 	colors="true"
+	executionOrder="random"
 	failOnRisky="true"
 	failOnWarning="true"
+	failOnEmptyTestSuite="true"
 	beStrictAboutChangesToGlobalState="true"
 	beStrictAboutCoversAnnotation="true"
 	beStrictAboutOutputDuringTests="true"
diff --git a/tests/PHPStan/Command/ErrorFormatter/TableErrorFormatterTest.php b/tests/PHPStan/Command/ErrorFormatter/TableErrorFormatterTest.php
index 5232f164ff..5863760fef 100644
--- a/tests/PHPStan/Command/ErrorFormatter/TableErrorFormatterTest.php
+++ b/tests/PHPStan/Command/ErrorFormatter/TableErrorFormatterTest.php
@@ -24,6 +24,7 @@ protected function setUp(): void
 	protected function tearDown(): void
 	{
 		putenv('COLUMNS');
+		putenv('TERM_PROGRAM');
 	}
 
 	public function dataFormatterOutputProvider(): iterable
@@ -195,6 +196,7 @@ public function testFormatErrors(
 		}
 		$formatter = $this->createErrorFormatter(null);
 
+		// NOTE: extra env vars need to be cleared in tearDown()
 		foreach ($extraEnvVars as $envVar) {
 			putenv($envVar);
 		}