* source files.
             */
            if (Files.isDirectory(file)) {
                Map<Path, String> names = new HashMap<>();
                try (Stream<Path> subdirs = Files.list(file)) {
                    subdirs.filter(Files::isDirectory).forEach((subdir) -> {
                        Path mf = subdir.resolve(MODULE_INFO);

                if (isModuleHierarchy) {
                    // If module hierarchy is used, the directory names shall be the module names.
                    Path path = test.resolve(moduleName);
                    if (!Files.isDirectory(path)) {
                        // Main module without tests. It is okay.
                        continue;
                    }
                    subdir = path;
                }