static random fields should not be used with graalvm as they are seeded at compile time and thus not random anymore

commafeed-server/src/test/java/com/commafeed/backend/feed/ImageProxyUrlTest.java

@@ -1,12 +1,18 @@
 package com.commafeed.backend.feed;
 
 import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.ValueSource;
 
 class ImageProxyUrlTest {
 
+	@BeforeAll
+	static void init() {
+		ImageProxyUrl.generateKey();
+	}
+
 	@ParameterizedTest
 	@ValueSource(
 			strings = {