From f21427d7fa309dcc6229cca79c9f73f60564a7b3 Mon Sep 17 00:00:00 2001
From: Daniel Hensby <dan@hens.by>
Date: Sat, 7 Mar 2015 10:32:17 +0000
Subject: [PATCH] DOCS Explaining test suite nesting

---
 dev/SapphireTest.php                          |  2 +-
 .../06_Testing/00_Unit_Testing.md             | 38 ++++++++++++++-----
 2 files changed, 29 insertions(+), 11 deletions(-)

diff --git a/dev/SapphireTest.php b/dev/SapphireTest.php
index c0de44d29..aacb86c18 100644
--- a/dev/SapphireTest.php
+++ b/dev/SapphireTest.php
@@ -347,7 +347,7 @@ class SapphireTest extends PHPUnit_Framework_TestCase {
 		Injector::unnest();
 		Config::unnest();
 
-		if($this->extensionsToReapply || $this->extensionsToRemove || $this->extraDataObjects) {
+		if(!empty($this->extensionsToReapply) || !empty($this->extensionsToRemove) || !empty($this->extraDataObjects)) {
 			$this->resetDBSchema();
 		}
 	}
diff --git a/docs/en/02_Developer_Guides/06_Testing/00_Unit_Testing.md b/docs/en/02_Developer_Guides/06_Testing/00_Unit_Testing.md
index 1771e640b..7afd1894c 100644
--- a/docs/en/02_Developer_Guides/06_Testing/00_Unit_Testing.md
+++ b/docs/en/02_Developer_Guides/06_Testing/00_Unit_Testing.md
@@ -182,18 +182,10 @@ end of each test.
 				$page->publish('Stage', 'Live');
 			}
 
-			// reset configuration for the test.
-			Config::nest();
+			// set custom configuration for the test.
 			Config::inst()->update('Foo', 'bar', 'Hello!');
 		}
 
-		public function tearDown() {
-			// restores the config variables
-			Config::unnest();
-
-			parent::tearDown();
-		}
-
 		public function testMyMethod() {
 			// ..
 		}
@@ -223,6 +215,32 @@ individual test case.
 			// ..
 		}
 	}
+	
+### Config and Injector Nesting
+
+A powerful feature of both [`Config`](/developer_guides/configuration/configuration/) and [`Injector`](/developer_guides/extending/injector/) is the ability to "nest" them so that you can make changes that can easily be discarded without having to manage previous values.
+
+The testing suite makes use of this to "sandbox" each of the unit tests as well as each suite to prevent leakage between tests.
+
+If you need to make changes to `Config` (or `Injector) for each test (or the whole suite) you can safely update `Config` (or `Injector`) settings in the `setUp` or `tearDown` functions.
+
+It's important to remember that the `parent::setUp();` functions will need to be called first to ensure the nesting feature works as expected.
+
+	:::php
+	function setUpOnce() {
+		parent::setUpOnce();
+		//this will remain for the whole suite and be removed for any other tests
+		Config::inst()->update('ClassName', 'var_name', 'var_value');
+	}
+	
+	function testFeatureDoesAsExpected() {
+		//this will be reset to 'var_value' at the end of this test function
+		Config::inst()->update('ClassName', 'var_name', 'new_var_value');
+	}
+	
+	function testAnotherFeatureDoesAsExpected() {
+		Config::inst()->get('ClassName', 'var_name'); // this will be 'var_value'
+	}
 
 ## Generating a Coverage Report
 
@@ -266,4 +284,4 @@ some `thirdparty/` directories add the following to the `phpunit.xml` configurat
 
 * [api:TestRunner]
 * [api:SapphireTest]
-* [api:FunctionalTest]
\ No newline at end of file
+* [api:FunctionalTest]