diff --git a/NEWS b/NEWS
index 2d52c284..5481ccfc 100644
--- a/NEWS
+++ b/NEWS
@@ -43,6 +43,7 @@ NEWS ( CHANGELOG and HISTORY )                                     HTMLPurifier
 - Fix bug with trusted script handling in libxml versions later than 2.6.28.
 - Fix bug in ExtractStyleBlocks with comments in style tags
 - Fix bug in comment parsing for DirectLex
+- Flush output now displayed when in command line mode for unit tester
 . Plugins now get their own changelogs according to project conventions.
 . Convert tokens to use instanceof, reducing memory footprint and
   improving comparison speed.
diff --git a/library/HTMLPurifier.includes.php b/library/HTMLPurifier.includes.php
index 27094120..a18e2384 100644
--- a/library/HTMLPurifier.includes.php
+++ b/library/HTMLPurifier.includes.php
@@ -125,6 +125,7 @@ require 'HTMLPurifier/ConfigDef/DirectiveAlias.php';
 require 'HTMLPurifier/ConfigDef/Namespace.php';
 require 'HTMLPurifier/ConfigSchema/Exception.php';
 require 'HTMLPurifier/ConfigSchema/Interchange.php';
+require 'HTMLPurifier/ConfigSchema/InterchangeValidator.php';
 require 'HTMLPurifier/ConfigSchema/StringHash.php';
 require 'HTMLPurifier/ConfigSchema/StringHashAdapter.php';
 require 'HTMLPurifier/ConfigSchema/StringHashParser.php';
diff --git a/library/HTMLPurifier/ConfigSchema/Interchange.php b/library/HTMLPurifier/ConfigSchema/Interchange.php
index 47c1ce5a..09f49fa6 100644
--- a/library/HTMLPurifier/ConfigSchema/Interchange.php
+++ b/library/HTMLPurifier/ConfigSchema/Interchange.php
@@ -11,7 +11,7 @@ class HTMLPurifier_ConfigSchema_Interchange
     /**
      * Hash table of allowed types.
      */
-    private $types = array(
+    public $types = array(
         'string'    => 'String',
         'istring'   => 'Case-insensitive string',
         'text'      => 'Text',
@@ -28,29 +28,12 @@ class HTMLPurifier_ConfigSchema_Interchange
     /**
      * Array of Namespace ID => array(namespace info)
      */
-    private $namespaces;
+    public $namespaces;
     
     /**
      * Array of Directive ID => array(directive info)
      */
-    private $directives;
-    
-    /** Get all namespaces */
-    public function getNamespaces() {return $this->namespaces;}
-    /** Get a namespace */
-    public function getNamespace($id) {return $this->namespaces[$id];}
-    /** Check if a namespace exists */
-    public function namespaceExists($id) {return isset($this->namespaces[$id]);}
-    
-    /** Get all directives */
-    public function getDirectives() {return $this->directives;}
-    /** Get a directive */
-    public function getDirective($id) {return $this->directives[$id];}
-    /** Check if a directive exists */
-    public function directiveExists($id) {return isset($this->directives[$id]);}
-    
-    /** Get all types */
-    public function getTypes() {return $this->types;}
+    public $directives;
     
     /**
      * Adds a namespace array to $namespaces
@@ -71,7 +54,9 @@ class HTMLPurifier_ConfigSchema_Interchange
      * to be used for data-input.
      */
     public function getValidatorAdapter() {
-        
+        $validator = new HTMLPurifier_ConfigSchema_InterchangeValidator($this);
+        $validator->addValidator(new HTMLPurifier_ConfigSchema_Validator_IdExists());
+        return $validator;
     }
     
 }
diff --git a/library/HTMLPurifier/ConfigSchema/InterchangeValidator.php b/library/HTMLPurifier/ConfigSchema/InterchangeValidator.php
new file mode 100644
index 00000000..55a83bc6
--- /dev/null
+++ b/library/HTMLPurifier/ConfigSchema/InterchangeValidator.php
@@ -0,0 +1,45 @@
+<?php
+
+/**
+ * Decorator for interchange that performs validations
+ */
+class HTMLPurifier_ConfigSchema_InterchangeValidator
+{
+    protected $interchange;
+    protected $validators = array();
+    
+    /**
+     * @param $interchange Instance of HTMLPurifier_ConfigSchema_Interchange
+     *      to save changes to.
+     */
+    public function __construct($interchange) {
+        $this->interchange = $interchange;
+    }
+    
+    /**
+     * Registers a HTMLPurifier_ConfigSchema_Validator to run when adding.
+     */
+    public function addValidator($validator) {
+        $this->validators[] = $validator;
+    }
+    
+    /**
+     * Validates and adds a namespace hash
+     */
+    public function addNamespace($hash) {
+        foreach ($this->validators as $validator) {
+            $validator->validateNamespace($hash, $this->interchange);
+        }
+        $this->interchange->addNamespace($hash);
+    }
+    
+    /**
+     * Validates and adds a directive hash
+     */
+    public function addDirective($hash) {
+        foreach ($this->validators as $validator) {
+            $validator->validateDirective($hash, $this->interchange);
+        }
+        $this->interchange->addDirective($hash);
+    }
+}
diff --git a/tests/HTMLPurifier/ConfigSchema/InterchangeTest.php b/tests/HTMLPurifier/ConfigSchema/InterchangeTest.php
index d8c53e4b..1432e604 100644
--- a/tests/HTMLPurifier/ConfigSchema/InterchangeTest.php
+++ b/tests/HTMLPurifier/ConfigSchema/InterchangeTest.php
@@ -14,7 +14,7 @@ class HTMLPurifier_ConfigSchema_InterchangeTest extends UnitTestCase
             'ID' => 'Namespace',
             'DESCRIPTION' => 'Bar',
         ));
-        $this->assertIdentical($v, $this->interchange->getNamespace('Namespace'));
+        $this->assertIdentical($v, $this->interchange->namespaces['Namespace']);
     }
     
     public function testAddDirective() {
@@ -22,7 +22,13 @@ class HTMLPurifier_ConfigSchema_InterchangeTest extends UnitTestCase
             'ID' => 'Namespace.Directive',
             'DESCRIPTION' => 'Bar',
         ));
-        $this->assertIdentical($v, $this->interchange->getDirective('Namespace.Directive'));
+        $this->assertIdentical($v, $this->interchange->directives['Namespace.Directive']);
+    }
+    
+    public function testValidator() {
+        $adapter = $this->interchange->getValidatorAdapter();
+        $this->expectException(new HTMLPurifier_ConfigSchema_Exception('ID must exist in directive'));
+        $adapter->addDirective(array());
     }
     
 }
diff --git a/tests/HTMLPurifier/ConfigSchema/InterchangeValidatorTest.php b/tests/HTMLPurifier/ConfigSchema/InterchangeValidatorTest.php
new file mode 100644
index 00000000..1e42133f
--- /dev/null
+++ b/tests/HTMLPurifier/ConfigSchema/InterchangeValidatorTest.php
@@ -0,0 +1,33 @@
+<?php
+
+class HTMLPurifier_ConfigSchema_InterchangeValidatorTest extends UnitTestCase
+{
+    
+    public function setup() {
+        generate_mock_once('HTMLPurifier_ConfigSchema_Interchange');
+        $this->mock = new HTMLPurifier_ConfigSchema_InterchangeMock();
+        $this->validator = new HTMLPurifier_ConfigSchema_InterchangeValidator($this->mock);
+    }
+    
+    protected function makeValidator($expect_method, $expect_params) {
+        generate_mock_once('HTMLPurifier_ConfigSchema_Validator');
+        $validator = new HTMLPurifier_ConfigSchema_ValidatorMock();
+        $validator->expectOnce($expect_method, $expect_params);
+        return $validator;
+    }
+    
+    public function testAddNamespaceNullValidator() {
+        $hash = array('ID' => 'Namespace');
+        $this->mock->expectOnce('addNamespace', array($hash));
+        $this->validator->addNamespace($hash);
+    }
+    
+    public function testAddNamespaceWithValidators() {
+        $hash = array('ID' => 'Namespace');
+        $this->validator->addValidator($this->makeValidator('validateNamespace', array($hash, $this->mock)));
+        $this->validator->addValidator($this->makeValidator('validateNamespace', array($hash, $this->mock)));
+        $this->mock->expectOnce('addNamespace', array($hash));
+        $this->validator->addNamespace($hash);
+    }
+    
+}
diff --git a/tests/index.php b/tests/index.php
index 7d94fc26..45eab7c9 100755
--- a/tests/index.php
+++ b/tests/index.php
@@ -71,7 +71,11 @@ require 'HTMLPurifier/Harness.php';
 // Shell-script code is executed
 
 if ($AC['flush']) {
-    shell_exec($AC['php'] . ' ../maintenance/flush.php');
+    if (SimpleReporter::inCli() && !$AC['xml']) {
+        passthru($AC['php'] . ' ../maintenance/flush.php');
+    } else {
+        shell_exec($AC['php'] . ' ../maintenance/flush.php');
+    }
 }
 
 // Now, userland code begins to be executed