fix message

Author: stefanseifert

tooling/conga-aem-maven-plugin/src/test/java/io/wcm/devops/conga/plugins/aem/maven/allpackage/FileTestUtil.java

@@ -116,7 +116,7 @@ public static void assertFiles(File dir, String runmodeSuffix, ExpectedFile... e
    * @param fileNames Expected file names in directory
    */
   public static void assertDirectories(File dir, String... fileNames) {
-    assertTrue(dir.exists(), "file exists: " + dir.getPath());
+    assertTrue(dir.exists(), "directory exists: " + dir.getPath());
     assertTrue(dir.isDirectory(), "is directory: " + dir.getPath());
     Set<String> expectedDirectoryNames = ImmutableSet.copyOf(fileNames);
     Set<String> actualDirectoryNames = Collections.emptySet();