--- a/test/test_packager.py	Thu Mar 20 20:21:34 2008 +0000
+++ b/test/test_packager.py	Tue Apr 01 12:30:39 2008 +0000
@@ -1,4 +1,4 @@
-# Copyright (C) 2007 by Intevation GmbH
+# Copyright (C) 2007, 2008 by Intevation GmbH
 # Authors:
 # Bernhard Herzog <bh@intevation.de>
 #
@@ -14,7 +14,7 @@
 from treepkg.run import call
 from treepkg.cmdexpand import cmdexpand
 from treepkg.util import writefile
-from treepkg.packager import PackagerGroup
+from treepkg.packager import PackagerGroup, import_packager_module
 import treepkg.subversion as subversion
 import treepkg
 
@@ -344,3 +344,32 @@
                           [os.path.join(srcdir, filename)
                            for filename in ["test_1.0-1_i386.changes",
                                             "test_1.0-1_i386.deb"]])
+
+
+class TestImportPackagerModule(unittest.TestCase, FileTestMixin):
+
+    files = [("treepkg_importtest",
+              [("__init__.py", ""),
+               ("withtrack.py", "\n".join(["class PackageTrack:",
+                                           "    pass",
+                                           ""])),
+               ("notrack.py", "\n".join(["class SourcePackager:",
+                                         "    pass",
+                                         ""]))])]
+
+    def setUp(self):
+        self.directory = self.create_temp_dir(self.id())
+        self.create_files(self.directory, self.files)
+        self.old_path = sys.path
+        sys.path = [self.directory] + sys.path
+
+    def tearDown(self):
+        sys.path = self.old_path
+
+    def test_import_with_track(self):
+        module = import_packager_module("treepkg_importtest.withtrack")
+        self.failUnless(hasattr(module, "PackageTrack"))
+
+    def test_import_without_track(self):
+        module = import_packager_module("treepkg_importtest.notrack")
+        self.failUnless(hasattr(module, "PackageTrack"))

--- a/treepkg/packager.py	Thu Mar 20 20:21:34 2008 +0000
+++ b/treepkg/packager.py	Tue Apr 01 12:30:39 2008 +0000
@@ -13,6 +13,7 @@
 import logging
 import shutil
 import datetime
+import new
 
 import util
 import subversion
@@ -395,8 +396,28 @@
                 for revision in self.get_revision_numbers()]
 
 
+def import_packager_module(packager_class):
+    """Import the packager module named by packager_class.
+
+    The packager_class must be the full absolute module name for the
+    packager.  The module must either contain a class called
+    'PackageTrack' or a class called called 'SourcePackager'.  If it
+    doesn't have a 'PackageTrack' class, a 'PackageTrack' class and a
+    'RevisionPackager' class will be created the latter of which will
+    use the module's 'SourcePackager' class as source_packager_cls.
+    """
+    module = util.import_dotted_name(packager_class)
+    if not hasattr(module, "PackageTrack"):
+        module.RevisionPackager \
+            = new.classobj("RevisionPackager", (RevisionPackager,),
+                           dict(source_packager_cls=module.SourcePackager))
+        module.PackageTrack \
+            = new.classobj("PackageTrack", (PackageTrack,),
+                           dict(revision_packager_cls=module.RevisionPackager))
+    return module
+
 def create_package_track(packager_class, **kw):
-    module = util.import_dotted_name(packager_class)
+    module = import_packager_module(packager_class)
     return module.PackageTrack(**kw)