diff --git a/tests/php-unit-tests/unitary-tests/application/Session/SessionTest.php b/tests/php-unit-tests/unitary-tests/application/Session/SessionTest.php
index 5bfd8467b..1321d77a8 100644
--- a/tests/php-unit-tests/unitary-tests/application/Session/SessionTest.php
+++ b/tests/php-unit-tests/unitary-tests/application/Session/SessionTest.php
@@ -6,7 +6,7 @@ use Combodo\iTop\Application\Helper\Session;
 use Combodo\iTop\Test\UnitTest\ItopTestCase;
 
 /**
- * @runTestsInSeparateProcesses
+ * @runClassInSeparateProcess Required because PHPUnit outputs something earlier, thus causing the headers to be sent
  */
 class SessionTest extends ItopTestCase
 {
@@ -24,18 +24,9 @@ class SessionTest extends ItopTestCase
 
 	/**
 	 * @covers \Combodo\iTop\Application\Helper\Session::Start
-	 */
-	public function testStart()
-	{
-		$this->assertNull(Session::$iSessionId);
-		Session::Start();
-		$this->assertNotNull(Session::$iSessionId);
-	}
-
-	/**
 	 * @covers \Combodo\iTop\Application\Helper\Session::WriteClose
 	 */
-	public function testWriteClose()
+	public function testStartWriteClose()
 	{
 		$this->assertNull(Session::$iSessionId);
 		Session::Start();
diff --git a/tests/php-unit-tests/unitary-tests/core/apcEmulationTest.php b/tests/php-unit-tests/unitary-tests/core/apcEmulationTest.php
index 6dc3d95ee..3623fa6a4 100644
--- a/tests/php-unit-tests/unitary-tests/core/apcEmulationTest.php
+++ b/tests/php-unit-tests/unitary-tests/core/apcEmulationTest.php
@@ -32,7 +32,7 @@ define('UNIT_MAX_CACHE_FILES', 10);
 
 
 /**
- * @runTestsInSeparateProcesses
+ * @runTestsInSeparateProcesses Required (at least) to mock the MetaModel and utils class
  */
 class apcEmulationTest extends ItopTestCase
 {
diff --git a/tests/php-unit-tests/unitary-tests/sources/application/status/StatusIncTest.php b/tests/php-unit-tests/unitary-tests/sources/application/status/StatusIncTest.php
index 0ed673c3f..5a9c705ff 100644
--- a/tests/php-unit-tests/unitary-tests/sources/application/status/StatusIncTest.php
+++ b/tests/php-unit-tests/unitary-tests/sources/application/status/StatusIncTest.php
@@ -66,7 +66,7 @@ class StatusIncTest extends ItopTestCase {
     }
 
     /**
-     * @runInSeparateProcess
+     * @runInSeparateProcess Required because Status constructor invokes MetaModel::Startup... which does nothing when already loaded
      */
 	public function testStatusStartupWrongDbPwd()
     {