diff --git a/tests/main/inc/lib/document.lib.test.php b/tests/main/inc/lib/document.lib.test.php
index 4e894c8265..f9cc19ea63 100755
--- a/tests/main/inc/lib/document.lib.test.php
+++ b/tests/main/inc/lib/document.lib.test.php
@@ -235,7 +235,7 @@ class TestDocumentManager extends UnitTestCase {
 		if (!headers_sent()) {	
 			$res=DocumentManager::string_send_for_download($full_string, $forced, $name);
 		}
-		$this->assertTrue($res);
+		$this->assertFalse(empty($res));
 	}
 
 	/**
diff --git a/tests/main/inc/lib/main_api.lib.test.php b/tests/main/inc/lib/main_api.lib.test.php
index fd41d95900..5ead944079 100755
--- a/tests/main/inc/lib/main_api.lib.test.php
+++ b/tests/main/inc/lib/main_api.lib.test.php
@@ -603,17 +603,14 @@ class TestMainApi extends UnitTestCase {
 	}
 
 	function testApiChmod_R(){
+		// We know, it does not work for Windows.
+		if (IS_WINDOWS_OS) { return true; }
 		$dirname = api_get_path(SYS_LANG_PATH);
 		$perm_dir = substr(sprintf('%o', fileperms($dirname)), -4);
-		if ($perm_dir != '0777') {
-			// haha! This one is too good to remove... (for now)
-			$msg = "Error";
-			$this->assertTrue(is_string($msg));
-		} else {
-			$filemode = '0777';
-			$res = api_chmod_R($dirname, $filemode);
-			$this->assertTrue($res || IS_WINDOWS_OS); // We know, it does not work for Windows.
-		}
+		$this->assertEqual($perm_dir,'0777');
+		$new_filemode = '0775';
+		$res = api_chmod_R($dirname, $new_filemode);
+		$this->assertTrue($res);
 	}
 
 	function testApiGetVersion(){
diff --git a/tests/main/inc/lib/usermanager.lib.test.php b/tests/main/inc/lib/usermanager.lib.test.php
index 47437dbc4a..2c131ebce9 100755
--- a/tests/main/inc/lib/usermanager.lib.test.php
+++ b/tests/main/inc/lib/usermanager.lib.test.php
@@ -115,9 +115,9 @@ class TestUserManager extends UnitTestCase {
     	$this->assertTrue(is_bool($res));
     }
 
-    function testBuildProductionList() {
-    	$res=UserManager::build_production_list(1, false, false);
-    	$this->assertTrue(is_string($res));
+    function testBuildProductionListIsFalse() {
+    	$res = UserManager::build_production_list(1, false, false);
+    	$this->assertFalse($res);
     }
 
 	function testDeleteApiKey() {