anchor.diff:  			printerr("    expect: '\(expect)'\n");
   		}
   	}
  -	tryPathStem("/foo/baz/baz.txt", expect: "baz");
  -	tryPathStem("/foo/baz/baz", expect: "baz");
  -	tryPathStem("/foo/baz//.config", expect: "");
  -	tryPathStem("/foo/baz/", expect: "");
  -	tryPathStem("/foo/", expect: "");
  -	tryPathStem("/", expect: "");
  -	tryPathStem("", expect: "");
  +	try_path_stem("/foo/baz/baz.txt", expect: "baz");
  +	try_path_stem("/foo/baz/baz", expect: "baz");
  +	try_path_stem("/foo/baz//.config", expect: "");
  +	try_path_stem("/foo/baz/", expect: "");
  +	try_path_stem("/foo/", expect: "");
  +	try_path_stem("/", expect: "");
  +	try_path_stem("", expect: "");
   }
   
   unittest std.io.path.normalize {
  -	var tryPathNormalize = func (cref path: string, cref expect: string) {
  +	var try_path_normalize = func (cref path: string, cref expect: string) {
   		var got = std.io.path.normalize(path);
   		if got != expect then {
   			printerr("error: fail '\(path)'\n");
  
positive.code: 			printerr("    expect: '\(expect)'\n");
  		}
  	}
  	tryPathFilename("/foo/baz/baz.txt", expect: "baz.txt");
  	tryPathFilename("/foo/baz/baz", expect: "baz");
  	tryPathFilename("/foo/baz//.config", expect: ".config");
  	tryPathFilename("/foo/baz/", expect: "");
  	tryPathFilename("/foo/", expect: "");
  	tryPathFilename("/", expect: "");
  	tryPathFilename("", expect: "");
  }
  
  unittest std.io.path.folder {
  	var tryPathFolder = func (cref path: string, cref expect: string) {
  		ref got = std.io.path.folder(path);
  		if got != expect then {
  			printerr("error: fail '\(path)'\n");
  
negative.code: 			printerr("    expect: '\(expect)'\n");
  		}
  	}
  	try_path_folder("/foo/baz/baz.txt", expect: "/foo/baz");
  	try_path_folder("/foo/baz/baz", expect: "/foo/baz");
  	try_path_folder("/foo/baz//.config", expect: "/foo/baz/");
  	try_path_folder("/foo/baz/", expect: "/foo/baz");
  	try_path_folder("/foo/", expect: "/foo");
  	try_path_folder("/", expect: "");
  	try_path_folder("", expect: "");
  }
  
  unittest std.io.path.parent {
  	var try_path_parent_folder = func (cref path: string, cref expect: string) {
  		ref got = std.io.path.parent(path);
  		if got != expect then {
  			printerr("error: fail '\(path)'\n");
  