Added snapshot & restore functions to make test cleanup easier

lib/index.js

@@ -60,6 +60,30 @@ function Config(parent, defaultEnvVar, customizer) {
     return settings.hasOwnProperty(setting) || (!!parent && parent.has(setting));
   };
 
+  config.snapshot = function () {
+    var snapshot = [{}, {}];
+    Object.keys(settings).forEach(function (key) {
+      snapshot[0][key] = settings[key];
+    });
+
+    Object.keys(environments).forEach(function (key) {
+      snapshot[1][key] = environments[key].snapshot();
+    });
+
+    return snapshot;
+  };
+
+  config.restore = function (snapshot) {
+    var self = this;
+    settings = snapshot[0];
+
+    environments = {};
+    Object.keys(snapshot[1]).forEach(function (key) {
+      environments[key] = new Config(self, defaultEnvVar, customizer);
+      environments[key].restore(snapshot[1][key]);
+    });
+  };
+
   Object.defineProperties(config, {
     default: {
       get: function () {

test/config-test.js

@@ -280,3 +280,49 @@ describe('Config customization', function () {
     spy.callCount.should.equal(2);
   });
 });
+
+describe('Snapshot and restore', function () {
+  it('should save and restore configuration state', function () {
+    var c = envconf.createConfig();
+    c.configure(function () {
+      c.set('first', 'one');
+      c.set('second', 'two');
+    });
+
+    var ss = c.snapshot();
+    c.set('first', 'changed');
+    c.set('added', 'new value');
+
+    c.restore(ss);
+
+    c.get('first').should.equal('one');
+    c.get('second').should.equal('two');
+    should.not.exist(c.get('added'));
+  });
+
+  it('should save and restore child environments', function () {
+    var c = envconf.createConfig();
+    c.configure('dev', function (dev) {
+      dev.set('devFirst', 'one');
+      dev.configure('devsub', function (devsub) {
+        devsub.set('subsubFirst', 'a sub sub value');
+      });
+    });
+
+    c.configure('prod', function (prod) {
+      prod.set('prodvalue', 'a value');
+    });
+
+    var snapshot = c.snapshot();
+
+    c('dev').set('devFirst', 'changed value');
+    c('prod').configure('addedEnvironment', function (added) {
+      added.set('newEnvValue', 1234);
+    });
+
+    c.restore(snapshot);
+
+    c('dev').get('devFirst').should.equal('one');
+    c('prod').environments.should.not.include('addedEnvironment');
+  });
+});