diff --git a/bin/test/test_InstallDB.py b/bin/test/test_InstallDB.py
index b75e6a06b..c0f2aaf37 100644
--- a/bin/test/test_InstallDB.py
+++ b/bin/test/test_InstallDB.py
@@ -1,77 +1,114 @@
 #!/usr/bin/env python
 # -*- coding: utf-8 -*-
 #
 # Copyright (c) 2012 by Intevation GmbH
 # All rights reserved.
 #
 # Authors:
 # Andre Heinecke <aheinecke@intevation.de>
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are met:
 #     * Redistributions of source code must retain the above copyright
 #       notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above copyright
 #       notice, this list of conditions and the following disclaimer in the
 #       documentation and/or other materials provided with the distribution.
 #     * Neither the name of Intevation GmbH nor the
 #       names of its contributors may be used to endorse or promote products
 #       derived from this software without specific prior written permission.
 #
 # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 # ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 # WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 # DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY
 # DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 # (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 # LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 # ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 # SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #
 
 
 """ Functional tests for InstallDB """
 
 import os
 import sys
 import unittest
+from multiprocessing import Process
 
 test_dir = os.path.dirname(__file__)
 sys.path.append(os.path.join(test_dir, os.pardir))
 os.environ["KDEROOT"] = test_dir
 
 import InstallDB
 
 tmp_dir = os.path.join(test_dir, "tmp")
 
 class DatabaseTest(unittest.TestCase):
 
     def setUp(self):
         if not os.path.isdir(tmp_dir):
             os.mkdir(tmp_dir)
         self.db = InstallDB.InstallDB(os.path.join(tmp_dir, "test.db"))
 
     def tearDown(self):
         os.remove(os.path.join(tmp_dir, "test.db"))
         try:
             os.rmdir(tmp_dir)
         except:
             print ("Could not delete %s. DB still open?", tmp_dir)
 
 class TestAPI(DatabaseTest):
 
     def test_addInstalled(self):
         package = self.db.addInstalled( 'win32libs-sources', 'dbus-src', '1.4.0', 0, False, 'release' )
         package.addFiles( dict().fromkeys( [ 'test', 'test1', 'test2' ], 'empty hash' ) )
         package.install()
-        self.assertEquals( self.db.isInstalled( 'win32libs-sources', 'dbus-src', '1.4.0' ), True)
-        self.assertEquals( self.db.isInstalled( None, 'dbus-src', '1.4.0', 0, 'release' ), True)
-        self.assertEquals( self.db.isInstalled( None, 'dbus-src', None, 'release' ), True)
-        self.assertEquals( self.db.isInstalled( None, 'dbus-src', None, None ), True)
+        self.assertEquals( self.db.isInstalled( 'win32libs-sources', 'dbus-src', '1.4.0' ), True )
+        self.assertEquals( self.db.isInstalled( None, 'dbus-src', '1.4.0', 0, 'release' ), True )
+        self.assertEquals( self.db.isInstalled( None, 'dbus-src', None, 'release' ), True )
+        self.assertEquals( self.db.isInstalled( None, 'dbus-src', None, None ), True )
 
     def test_uninstall(self):
         package = self.db.addInstalled( 'acategory', 'apackage', 'atarget', 0, False, 'release' )
         package.install()
         package.uninstall()
-        self.assertEquals( self.db.isInstalled( 'acategory', 'apackage', 'atarget' ), False)
+        self.assertEquals( self.db.isInstalled( 'acategory', 'apackage', 'atarget' ), False )
+        packages = self.db.getInstalled( None, 'apackage', None )
+        self.assertEquals( len(packages), 0 )
+
+    def test_prefixes(self):
+        package = self.db.addInstalled( 'acategory', 'apackage', 'atarget', 0, False, 'release' )
+        package.install()
+        package2 = self.db.addInstalled( 'acategory', 'apackage', 'atarget', 0, False, 'debug' )
+        package2.install()
+
+        # Test if prefixes are really not mixed
+        self.assertEquals( self.db.isInstalled( None, 'apackage', None, 0, 'release' ), True )
+        self.assertEquals( self.db.isInstalled( None, 'apackage', None, 0, 'debug' ), True )
+        packages = self.db.getInstalled( None, 'apackage', None, 'debug' )
+        self.assertEquals(len( packages ), 1)
+        packages[0].uninstall()
+        self.assertEquals( self.db.isInstalled( None, 'apackage', None, 0, 'release' ), True )
+        packages = self.db.getInstalled( None, 'apackage', None, 'debug' )
+        self.assertEquals( len( packages ), 0 )
+        packages = self.db.getInstalled( None, 'apackage', None, 'release' )
+        self.assertEquals(len(packages), 1)
+        packages[0].uninstall()
+        self.assertEquals( self.db.isInstalled( None, 'apackage', None, 0, 'release' ), False )
+
+    def helper_install(self, name):
+        package = self.db.addInstalled( 'acategory', name, 'atarget', 0, False, 'release' )
+        package.install()
+
+    def test_multiprocessing(self):
+        p = []
+        for i in range( 0, 100 ):
+            p.append( Process( target=self.helper_install, args=(i,) ) )
+            p[i].start()
+
+        for i in range( 0, 100 ):
+            p[i].join()
+