diff --git a/tests/php-unit-tests/src/Service/UnitTestRunTimeEnvironment.php b/tests/php-unit-tests/src/Service/UnitTestRunTimeEnvironment.php
index 9c4f50c4b8..60ab99547c 100644
--- a/tests/php-unit-tests/src/Service/UnitTestRunTimeEnvironment.php
+++ b/tests/php-unit-tests/src/Service/UnitTestRunTimeEnvironment.php
@@ -13,6 +13,7 @@ use RecursiveDirectoryIterator;
 use RecursiveIteratorIterator;
 use ReflectionClass;
 use RunTimeEnvironment;
+use SetupUtils;
 use utils;
 
 
@@ -47,55 +48,38 @@ class UnitTestRunTimeEnvironment extends RunTimeEnvironment
 		return $this->sFinalEnv;
 	}
 
+	public function CompileFrom($sSourceEnv, $bUseSymLinks = null)
+	{
+		$sDestModulesDir = APPROOT.'data/'.$this->sTargetEnv.'-modules/';
+		if (is_dir($sDestModulesDir)) {
+			SetupUtils::rrmdir($sDestModulesDir);
+		}
+
+		SetupUtils::copydir(APPROOT.'/data/'.$sSourceEnv.'-modules', $sDestModulesDir, $bUseSymLinks);
+
+		parent::CompileFrom($sSourceEnv, $bUseSymLinks);
+	}
+
     public function IsUpToDate()
     {
         clearstatcache();
-	    $aCustomDatamodelFiles = $this->GetCustomDatamodelFiles();
-	    $sDestDir = APPROOT.'env-'.$this->sFinalEnv;
-	    if (! is_dir($sDestDir) && count($aCustomDatamodelFiles) > 0){
-		    $this->PrintFiles($aCustomDatamodelFiles);
-		    return false;
-		}
-
-	    $fLastCompilationTime = filemtime($sDestDir);
-		if (false === $fLastCompilationTime){
-			echo "Issue when calling filemtime($sDestDir) \n";
-			return true;
-		}
-
-		echo "files in $sDestDir: ". var_export(glob("$sDestDir/*"), true) . "\n" ;
-
-	    $sLastCompilationDate = date("Y-m-d H:i:s", $fLastCompilationTime);
-	    echo "filemtime($sDestDir): $fLastCompilationTime " .$sLastCompilationDate." \n";
-
+        $fLastCompilationTime = filemtime(APPROOT.'env-'.$this->sFinalEnv);
 	    $aModifiedFiles = [];
-
-		foreach ($aCustomDatamodelFiles as $sCustomDatamodelFile) {
-			$iFilemtime = filemtime($sCustomDatamodelFile);
-			if ($iFilemtime > $fLastCompilationTime) {
+        $this->FindFilesModifiedAfter($fLastCompilationTime, APPROOT.'datamodels/2.x', $aModifiedFiles);
+        $this->FindFilesModifiedAfter($fLastCompilationTime, APPROOT.'extensions', $aModifiedFiles);
+        $this->FindFilesModifiedAfter($fLastCompilationTime, APPROOT.'data/production-modules', $aModifiedFiles);
+        foreach ($this->GetCustomDatamodelFiles() as $sCustomDatamodelFile) {
+            if (filemtime($sCustomDatamodelFile) > $fLastCompilationTime) {
                 $aModifiedFiles[] = $sCustomDatamodelFile;
-            } else {
-				//nervous breakdown troubleshooting!
-	            echo sprintf("%s:\nlast compilation: %s vs (mtime of current file) %s \n",
-		            $sCustomDatamodelFile, $sLastCompilationDate, date("Y-m-d H:i:s", $iFilemtime));
             }
         }
-
         if (count($aModifiedFiles) > 0) {
-	        $this->PrintFiles($aModifiedFiles);
-			return false;
-        }
-
-		return false;
-    }
-
-	private function PrintFiles(array $aFiles, string $sMsg = "The following files have been modified after the last compilation") : void
-	{
-		echo "$sMsg:\n";
-		foreach ($aFiles as $sFile) {
+            echo "The following files have been modified after the last compilation:\n";
+            foreach ($aModifiedFiles as $sFile) {
 			echo " - $sFile\n";
 		}
-		echo "\n";
+        }
+        return (count($aModifiedFiles) === 0);
 	}
 
     /**
@@ -159,14 +143,12 @@ class UnitTestRunTimeEnvironment extends RunTimeEnvironment
 				if ($sClass === '') {
 					continue;
 				}
-
 				if (in_array($sClass, $aLoadedTestClasses)) {
+					echo "class $sClass already loaded somehow \n";
 					continue;
 				}
-
 				$aLoadedTestClasses[]=$sClass;
                 require_once $sFile;
-
 				$oReflectionClass = new ReflectionClass($sClass);
 				if ($oReflectionClass->isAbstract()) {
 					continue;
@@ -190,7 +172,6 @@ class UnitTestRunTimeEnvironment extends RunTimeEnvironment
 			}
 		}
 
-		$this->PrintFiles($this->aCustomDatamodelFiles, "Found XML delta files");
 		return $this->aCustomDatamodelFiles;
 	}