Adding test for invalid precision value

Author: avoidwork

test/filesize_test.js

@@ -197,9 +197,10 @@ exports.filesize = {
 		test.done();
 	},
 	precision: function (test) {
-		test.expect(4);
+		test.expect(5);
 		test.equal(filesize(1024 * 1, {precision: 3}), "1.00 KB", "Should be '1.00 KB'");
-		test.equal(filesize(1024 * 1024 * 10.25, {precision: 3}), "10.3 MB", "Should be '21.0 KB'");
+		test.equal(filesize(1024 * 1024 * 10.25, {precision: 3}), "10.3 MB", "Should be '10.3 MB'");
+		test.equal(filesize(1024 * 1024 * 10.25, {precision: "x"}), "10.25 MB", "Should be '10.25 MB'");
 		test.equal(filesize(1024 * 1024 * 1024, {precision: 3}), "1.00 GB", "Should be '1.00 GB'");
 		test.equal(filesize(Math.pow(1024, 10), {precision: 3}), "1e+6 YB", "Should be '1e+6 YB'");
 		test.done();