Add unit-tests for list-processing. Fix edge-cases.

Author: josteink

src/gmail.js

@@ -147,15 +147,21 @@ var Gmail_ = function(localJQuery) {
             localePrefix.toUpperCase() === localePrefix;
     };
 
-    var arrayStartsWith = function(list, item) {
-        return (list && list.length > 0 && list[0] === item);
+    api.helper.array_starts_with = function(list, item) {
+        if (list && list.length > 0 && list[0] === item) {
+            return true;
+        } else {
+            return false;
+        }
     };
 
-    var findArraySubList = function(nestedArray, itemKey) {
-        for(var i=0; i<nestedArray.length; i++) {
-            var list = nestedArray[i];
-            if (arrayStartsWith(list, itemKey)) {
-                return list;
+    api.helper.get.array_sublist = function(nestedArray, itemKey) {
+        if (nestedArray) {
+            for(var i=0; i<nestedArray.length; i++) {
+                var list = nestedArray[i];
+                if (api.helper.array_starts_with(list, itemKey)) {
+                    return list;
+                }
             }
         }
 
@@ -200,7 +206,7 @@ var Gmail_ = function(localJQuery) {
 
         // candidate is globals[17]-subarray which starts with "ui"
         // has historically been observed as [7], [8] and [9]!
-        var localeList = findArraySubList(globals[17], "ui");
+        var localeList = api.helper.get.array_sublist(globals[17], "ui");
         if (localeList !== null && localeList.length > 8) {
             var locale = getLocaleFromGlobalsItem(localeList);
             if (api.helper.get.is_locale(locale)) {

test/test.parsing.js

@@ -130,3 +130,51 @@ describe("Name-parsing", () => {
         testName("Senõr Alapenõ on a stick");
     });
 });
+
+describe("List-prefix checking", () => {
+    const gmail = new Gmail();
+
+    const testCase = function(list, searchee, expected) {
+        const result = gmail.helper.array_starts_with(list, searchee);
+        assert.equal(expected, result);
+    };
+
+    it("returns false for null or empty list", () => {
+        testCase(null, "key", false);
+        testCase([], "key", false);
+    });
+
+    it("returns false for miss", () => {
+        testCase(["ui", "yes"], "uiv", false);
+    });
+
+    it("returns true for exact hit", () => {
+        testCase(["ui", "yes"], "ui", true);
+    });
+});
+
+describe("Sub-list extraction", () => {
+    const gmail = new Gmail();
+
+    const testCase = function(listlist, prefix, expected) {
+        const result = gmail.helper.get.array_sublist(listlist, prefix);
+        assert.deepEqual(expected, result);
+    };
+
+    it("returns null for null or empty list", () => {
+        testCase(null, "ui", null);
+        testCase([], "ui", null);
+    });
+
+    it("returns null for no match", () => {
+        testCase([["uiv", "a"]], "ui", null);
+    });
+
+    it("returns the full matching list on match", () => {
+        testCase([
+            ["a", "b", "c"],
+            ["ui", "yeah"],
+            ["d", "e", "f"]
+        ], "ui", ["ui", "yeah"]);
+    });
+});