[Fixed Position] Add spec for LineHandle

Add tests for handles for positioning end point of lines
in fixed position view, WTD-882.

platform/features/layout/test/elements/LineHandleSpec.js

@@ -0,0 +1,53 @@
+/*global define,describe,it,expect,beforeEach,jasmine,xit*/
+
+define(
+    ['../../src/elements/LineHandle'],
+    function (LineHandle) {
+        "use strict";
+
+        describe("A fixed position drag handle", function () {
+            var testElement,
+                handle;
+
+            beforeEach(function () {
+                testElement = {
+                    x: 3,
+                    y: 42,
+                    x2: 8,
+                    y2: 11
+                };
+
+                handle = new LineHandle(testElement, 'x', 'y', 'x2', 'y2');
+            });
+
+            it("provides x/y grid coordinates for its corner", function () {
+                expect(handle.x()).toEqual(3);
+                expect(handle.y()).toEqual(42);
+            });
+
+            it("changes x and y positions", function () {
+                handle.x(30);
+                expect(testElement.x).toEqual(30);
+                handle.y(40);
+                expect(testElement.y).toEqual(40);
+            });
+
+            it("disallows values less than zero", function () {
+                handle.x(-1);
+                handle.y(-400);
+                expect(testElement.x).toEqual(0);
+                expect(testElement.y).toEqual(0);
+            });
+
+            it("ensures that end points remain different", function () {
+                handle.x(testElement.x2);
+                handle.y(testElement.y2);
+                // First change should have been fine, because y was different
+                expect(testElement.x).toEqual(testElement.x2);
+                // Second change should have been rejected
+                expect(testElement.y).not.toEqual(testElement.y2);
+            });
+
+        });
+    }
+);