Allow lithium\Environment::reset() to remove a specific env only fo…

…r testing purpose.

core/Environment.php

@@ -117,9 +117,13 @@ class Environment {
 	 * environment, removing any environment-specific configurations, and removing the custom
 	 * environment detector, if any has been specified.
 	 *
-	 * @return void
+	 * @param $env If set, delete the defined environment only.
 	 */
-	public static function reset() {
+	public static function reset($env = null) {
+		if ($env) {
+			unset(static::$_configurations[$env]);
+			return;
+		}
 		static::$_current = '';
 		static::$_detector = null;
 		static::$_configurations = array(

tests/cases/core/EnvironmentTest.php

@@ -166,7 +166,7 @@ public function testDetectionWithArrayMap() {
 	/**
 	 * Tests resetting the `Environment` class to its default state.
 	 */
-	public function testReset() {
+	public function testResetAll() {
 		Environment::set('test', array('foo' => 'bar'));
 		Environment::set('test');
 		$this->assertEqual('test', Environment::get());
@@ -177,6 +177,22 @@ public function testReset() {
 		$this->assertNull(Environment::get('foo'));
 	}
 
+	public function testResetASpecificEnv() {
+		Environment::set('test', array('foo' => 'bar'));
+		Environment::set('development', array('hello' => 'world'));
+
+		Environment::set('test');
+		$this->assertEqual('test', Environment::get());
+		$this->assertEqual('bar', Environment::get('foo'));
+
+		Environment::reset('test');
+		$this->assertEqual('test', Environment::get());
+		$this->assertNull(Environment::get('foo'));
+
+		Environment::set('development');
+		$this->assertEqual('world', Environment::get('hello'));
+	}
+
 	/**
 	 * Tests using a custom detector to get the current environment.
 	 */