diff --git a/packages/tools/lib/test-runner/test-runner.js b/packages/tools/lib/test-runner/test-runner.js
index c968a7149bef..136a08ac5969 100644
--- a/packages/tools/lib/test-runner/test-runner.js
+++ b/packages/tools/lib/test-runner/test-runner.js
@@ -3,69 +3,77 @@ const { readFileSync } = require("fs");
 const path = require("path");
 const fs = require("fs");
 
-// search for dev-server port 
+function testFn() {
+// search for dev-server port
 // start in current folder
 // traversing upwards in case of mono repo tests and dev-server running in root folder of repository
-let devServerFolder = process.cwd();
-let devServerPort;
-while (true) {
-    try {
-        devServerPort = readFileSync(path.join(devServerFolder, ".dev-server-port")).toString();
-        break; // found
-    } catch (e) {
-        // file not found
-        if (devServerFolder === path.dirname(devServerFolder)) {
-            break; // reached root folder "/"
-        }
-        devServerFolder = path.dirname(devServerFolder);
-    }
-}
+	let devServerFolder = process.cwd();
+	let devServerPort;
+	while (true) {
+		try {
+			devServerPort = readFileSync(path.join(devServerFolder, ".dev-server-port")).toString();
+			break; // found
+		} catch (e) {
+			// file not found
+			if (devServerFolder === path.dirname(devServerFolder)) {
+				break; // reached root folder "/"
+			}
+			devServerFolder = path.dirname(devServerFolder);
+		}
+	}
 
 // check if we are in a monorepo and extract path from package.json
-let packageRepositoryPath = "";
-const pkg = require(path.join(process.cwd(), "package.json"));
-packageRepositoryPath = pkg.repository ? pkg.repository.directory : "";
+	let packageRepositoryPath = "";
+	const pkg = require(path.join(process.cwd(), "package.json"));
+	packageRepositoryPath = pkg.repository ? pkg.repository.directory : "";
 
 // construct base url
 // use devServerPort if a dev server is running, otherwise let the baseUrl in the wdio config be used
 // if a dev server is running in the root of a mono repo, append tha package path like this
 // http://localhost:${devServerPort}/packages/main/
-let baseUrl = "";
-if (devServerPort) {
-    console.log(`Found port ${devServerPort} from '${path.join(devServerFolder, ".dev-server-port")}'`);
-    const devServerInRoot = !devServerFolder.includes(packageRepositoryPath);
-    if (devServerInRoot) {
-        baseUrl = `--base-url http://localhost:${devServerPort}/${packageRepositoryPath}/`;
-    } else {
-        baseUrl = `--base-url http://localhost:${devServerPort}/`;
-    }
-}
+	let baseUrl = "";
+	if (devServerPort) {
+		console.log(`Found port ${devServerPort} from '${path.join(devServerFolder, ".dev-server-port")}'`);
+		const devServerInRoot = !devServerFolder.includes(packageRepositoryPath);
+		if (devServerInRoot) {
+			baseUrl = `--base-url http://localhost:${devServerPort}/${packageRepositoryPath}/`;
+		} else {
+			baseUrl = `--base-url http://localhost:${devServerPort}/`;
+		}
+	}
 
-if (!baseUrl) {
-    console.log("No dev server running, running tests served from `dist`, make sure it is up to date");
-}
+	if (!baseUrl) {
+		console.log("No dev server running, running tests served from `dist`, make sure it is up to date");
+	}
 
 // add single spec parameter if passed
-let spec = "";
-if (process.argv.length === 3) {
-    const specFile = process.argv[2];
-    spec = `--spec ${specFile}`;
-}
+	let spec = "";
+	if (process.argv.length === 3) {
+		const specFile = process.argv[2];
+		spec = `--spec ${specFile}`;
+	}
 
 // more parameters - pass them to wdio
-let restParams = "";
-if (process.argv.length > 3) {
-    restParams = process.argv.slice(2).join(" ");
+	let restParams = "";
+	if (process.argv.length > 3) {
+		restParams = process.argv.slice(2).join(" ");
+	}
+
+	let wdioConfig = "";
+	if (fs.existsSync("config/wdio.conf.cjs")) {
+		wdioConfig = "config/wdio.conf.cjs";
+	} else if (fs.existsSync("config/wdio.conf.js")) {
+		wdioConfig = "config/wdio.conf.js";
+	}
+
+// run wdio with calculated parameters
+	const cmd = `yarn cross-env WDIO_LOG_LEVEL=error wdio ${wdioConfig} ${spec} ${baseUrl} ${restParams}`;
+	console.log(`executing: ${cmd}`);
+	child_process.execSync(cmd, {stdio: 'inherit'});
 }
 
-let wdioConfig = "";
-if (fs.existsSync("config/wdio.conf.cjs")) {
-    wdioConfig = "config/wdio.conf.cjs";
-} else if (fs.existsSync("config/wdio.conf.js")) {
-    wdioConfig = "config/wdio.conf.js";
+if (require.main === module) {
+	testFn(process.argv)
 }
 
-// run wdio with calculated parameters
-const cmd = `yarn cross-env WDIO_LOG_LEVEL=error wdio ${wdioConfig} ${spec} ${baseUrl} ${restParams}`;
-console.log(`executing: ${cmd}`);
-child_process.execSync(cmd, {stdio: 'inherit'});
+exports._ui5mainFn = testFn;