Add support for ordering tags by the 'list-before' and 'list-after' fields

See the discussion here:

https://groups.google.com/d/topic/tiddlywikidev/AXDJEjcAphs/discussion

editions/test/tiddlers/tests/test-tags.js

@@ -0,0 +1,91 @@
+/*\
+title: test-tags.js
+type: application/javascript
+tags: [[$:/tags/test-spec]]
+
+Tests the tagging mechanism.
+
+\*/
+(function(){
+
+/*jslint node: true, browser: true */
+/*global $tw: false */
+"use strict";
+
+describe("Tag tests", function() {
+
+	// Create a wiki
+	var wiki = new $tw.Wiki();
+
+	// Add a few  tiddlers
+	wiki.addTiddler({
+		title: "TiddlerOne",
+		text: "The quick brown fox in $:/TiddlerTwo",
+		tags: ["one","TiddlerSeventh"],
+		modifier: "JoeBloggs",
+		modified: "201304152222"});
+	wiki.addTiddler({
+		title: "$:/TiddlerTwo",
+		text: "The rain in Spain\nfalls mainly on the plain and [[a fourth tiddler]]",
+		tags: ["two"],
+		modifier: "JohnDoe",
+		modified: "201304152211"});
+	wiki.addTiddler({
+		title: "Tiddler Three",
+		text: "The speed of sound in light\n\nThere is no TiddlerZero but TiddlerSix",
+		tags: ["one","two","TiddlerSeventh"],
+		modifier: "JohnDoe",
+		modified: "201304162202"});
+	wiki.addTiddler({
+		title: "a fourth tiddler",
+		text: "The quality of mercy is not drained by [[Tiddler Three]]",
+		tags: ["TiddlerSeventh"],
+		modifier: "JohnDoe"});
+	wiki.addTiddler({
+		title: "one",
+		text: "This is the text of tiddler [[one]]",
+		list: "[[Tiddler Three]] [[TiddlerOne]]",
+		modifier: "JohnDoe"});
+	wiki.addTiddler({
+		title: "$:/TiddlerFive",
+		text: "Everything in federation",
+		tags: ["two"]});
+	wiki.addTiddler({
+		title: "TiddlerSix",
+		text: "Missing inaction from TiddlerOne",
+		tags: []});
+	wiki.addTiddler({
+		title: "TiddlerSeventh",
+		text: "",
+		list: "TiddlerOne [[Tiddler Three]] [[a fourth tiddler]] MissingTiddler",
+		tags: []});
+	wiki.addTiddler({
+		title: "Tiddler8",
+		text: "Tidd",
+		tags: [],
+		"test-field": "JoeBloggs"});
+	wiki.addTiddler({
+		title: "Tiddler9",
+		text: "Another tiddler",
+		tags: ["TiddlerSeventh"],
+		"list-before": "a fourth tiddler"});
+	wiki.addTiddler({
+		title: "Tiddler10",
+		text: "Another tiddler",
+		tags: ["TiddlerSeventh"],
+		"list-before": ""});
+	wiki.addTiddler({
+		title: "Tiddler11",
+		text: "Another tiddler",
+		tags: ["TiddlerSeventh"],
+		"list-after": "Tiddler Three"});
+
+	// Our tests
+
+	it("should handle custom tag ordering", function() {
+		expect(wiki.filterTiddlers("[tag[TiddlerSeventh]]").join(",")).toBe("Tiddler10,TiddlerOne,Tiddler11,Tiddler Three,Tiddler9,a fourth tiddler");
+	});
+
+});
+
+})();