[Plot] Fill in specs

Fill in specs for elements used by the PlotController
in order to improve coverage of the plot bundle.
WTD-533.

platform/features/plot/test/elements/PlotFormatterSpec.js

@@ -9,6 +9,21 @@ define(
         "use strict";
 
         describe("The plot formatter", function () {
+            var formatter;
+
+            beforeEach(function () {
+                formatter = new PlotFormatter();
+            });
+
+            it("formats domains using YYYY-DDD style", function () {
+                expect(formatter.formatDomainValue(402513731000)).toEqual(
+                    "1982-276 17:22:11"
+                );
+            });
+
+            it("formats ranges as values", function () {
+                expect(formatter.formatRangeValue(10)).toEqual("10.0");
+            });
         });
     }
 );