Fix settings emptied out on save.

test/test_utils.js

 /*
 This file is part of the Juju GUI, which lets users view and manage Juju
 environments within a graphical interface (https://launchpad.net/juju-gui).
 Copyright (C) 2012-2013 Canonical Ltd.
 
 This program is free software: you can redistribute it and/or modify it under
 the terms of the GNU Affero General Public License version 3, as published by
 the Free Software Foundation.
 
 This program is distributed in the hope that it will be useful, but WITHOUT
@@ skipping 267 matching lines @@
       assert.strictEqual('mysql', result.near.service, 'near service');
       assert.strictEqual('provider', result.near.role, 'near role');
       assert.strictEqual('mydb', result.near.name, 'near name');
       assert.strictEqual('mediawiki', result.far.service, 'far service');
       assert.strictEqual('requirer', result.far.role, 'far role');
       assert.strictEqual('db', result.far.name, 'far name');
     });
 
   });
 
+  describe('getChangedConfigOptions', function() {
+    var getChangedConfigOptions;
+
+    before(function() {
+      getChangedConfigOptions = utils.getChangedConfigOptions;
+    });
+
+    it('returns undefined if no config options are provided', function() {
+      assert.isUndefined(getChangedConfigOptions(null, {}));
+    });
+
+    it('returns an empty object if an empty config is provided', function() {
+      var newValues = getChangedConfigOptions({}, {foo: 'bar'});
+      assert.deepEqual(newValues, {});
+    });
+
+    it('returns an empty object if no service changes are found', function() {
+      var newValues = getChangedConfigOptions({foo: 'bar'}, {foo: 'bar'});
+      assert.deepEqual(newValues, {});
+    });
+
+    it('returns an empty object if no charm changes are found', function() {
+      var charmConfig = {foo: {default: 'bar'}};
+      var newValues = getChangedConfigOptions({foo: 'bar'}, charmConfig);
+      assert.deepEqual(newValues, {});
+    });
+
+    it('returns changes if they are found on the service', function() {
+      var serviceConfig = {
+        key1: 'value1',
+        key2: 'value2',
+        key3: true,
+        key4: false,
+        key5: 5,
+        key6: 6
+      };
+      var newConfig = {
+        key1: 'value1',
+        key2: 'CHANGED!',
+        key3: true,
+        key4: true,
+        key5: 5,
+        key6: 42
+      };
+      var newValues = getChangedConfigOptions(newConfig, serviceConfig);
+      assert.deepEqual(newValues, {key2: 'CHANGED!', key4: true, key6: 42});
+    });
+
+    it('returns changes if they are found on the charm', function() {
+      var charmConfig = {
+        key1: {default: 'value1'},
+        key2: {default: 'value2'},
+        key3: {default: true},
+        key4: {default: false},
+        key5: {default: 5},
+        key6: {default: 6}
+      };
+      var newConfig = {
+        key1: 'value1',
+        key2: 'CHANGED!',
+        key3: true,
+        key4: true,
+        key5: 5,
+        key6: 42
+      };
+      var newValues = getChangedConfigOptions(newConfig, charmConfig);
+      assert.deepEqual(newValues, {key2: 'CHANGED!', key4: true, key6: 42});
+    });
+
+    it('returns all the changes if the existing config is empty', function() {
+      var newValues = getChangedConfigOptions({key1: 'value', key2: 42}, {});
+      assert.deepEqual(newValues, {key1: 'value', key2: 42});
+    });
+
+    it('does not modify in place the passed new config object', function() {
+      var newConfig = {key1: 'CHANGED!', key2: 42};
+      getChangedConfigOptions(newConfig, {key1: 'value', key2: 42});
+      assert.deepEqual(newConfig, {key1: 'CHANGED!', key2: 42});
+    });
+
+    it('does not modify in place the passed existing config', function() {
+      var serviceConfig = {key1: 'value', key2: 42};
+      getChangedConfigOptions({key1: 'CHANGED!', key2: 42}, serviceConfig);
+      assert.deepEqual(serviceConfig, {key1: 'value', key2: 42});
+    });
+
+  });
+
 });
 
 (function() {
   describe('form validation', function() {
 
     var utils, Y;
 
     before(function(done) {
       Y = YUI(GlobalConfig).use('juju-views',
 
@@ skipping 856 matching lines @@
       var url = utils.getLandscapeURL(environment, unit, 'security');
       var expected = makeURL(
           '+unit:django-42/+alert:security-upgrades/packages/list' +
           '?filter=security');
       assert.strictEqual(url, expected);
     });
 
   });
 
 })();