diff --git a/tests/runner/createTestServer.js b/tests/runner/createTestServer.js
index 67770c71d8..6f409bea2f 100644
--- a/tests/runner/createTestServer.js
+++ b/tests/runner/createTestServer.js
@@ -23,8 +23,9 @@ export async function createTestServer( report ) {
 
 	// Add a script tag to HTML pages to load the QUnit listeners
 	app.use( /\/tests\/unit\/([^/]+)\/\1\.html$/, async( req, res ) => {
+		const moduleEscaped = req.params[ 0 ].replace( /[^a-z0-9_-]/gi, "" );
 		const html = await readFile(
-			`tests/unit/${ req.params[ 0 ] }/${ req.params[ 0 ] }.html`,
+			`tests/unit/${ moduleEscaped }/${ moduleEscaped }.html`,
 			"utf8"
 		);
 		res.send(