[gjs] coverage: improve testSystem code coverage tests

[Philip Chimento <pchimento src gnome org>]

commit c1443c612579e1b8aa082a46fc280b1e3b5d315c
Author: Claudio André <claudioandre br gmail com>
Date:   Fri Feb 10 10:48:00 2017 -0500

    coverage: improve testSystem code coverage tests
    
    https://bugzilla.gnome.org/show_bug.cgi?id=777752

 installed-tests/js/testSystem.js |   17 ++++++++++++++++-
 1 files changed, 16 insertions(+), 1 deletions(-)
---
diff --git a/installed-tests/js/testSystem.js b/installed-tests/js/testSystem.js
index 66a868e..1211de4 100644
--- a/installed-tests/js/testSystem.js
+++ b/installed-tests/js/testSystem.js
@@ -1,4 +1,5 @@
 const System = imports.system;
+const GObject = imports.gi.GObject;
 
 describe('System.addressOf()', function () {
     it('gives different results for different objects', function () {
@@ -10,6 +11,20 @@ describe('System.addressOf()', function () {
 
 describe('System.version', function () {
     it('gives a plausible number', function () {
-        expect(System.version).not.toBeLessThan(13600);
+        expect(System.version).not.toBeLessThan(14700);
+        expect(System.version).toBeLessThan(20000);
+    });
+});
+
+describe('System.refcount()', function () {
+    it('gives the correct number', function () {
+        let o = new GObject.Object({});
+        expect(System.refcount(o)).toEqual(1);
+    });
+});
+
+describe('System.gc()', function () {
+    it('does not crash the application', function () {
+        expect(System.gc).not.toThrow();
     });
 });