fix(package): resolve source paths relative to package root

tests/test_package.py

@@ -356,7 +356,12 @@ class PackageTests(unittest.TestCase):
             original_cwd = os.getcwd()
             try:
                 os.chdir(tmp)
-                self.assertEqual(updater._source_directory(), ROOT)
+                source_root = updater._source_directory()
+                self.assertFalse(os.path.isabs(source_root))
+                self.assertTrue((Path(source_root) / 'WAPT' / 'control').is_file())
+                self.assertEqual(Path(source_root).resolve(), ROOT)
+                os.chdir(ROOT)
+                self.assertEqual(updater._source_directory(), Path('.'))
             finally:
                 os.chdir(original_cwd)
 
@@ -385,6 +390,19 @@ class PackageTests(unittest.TestCase):
                 updater._load_tool = old_loader
             self.assertEqual([call[0] for call in calls], ['vendor', 'manifest', 'verify'] * 2)
 
+    def test_setup_source_directory_is_relative_to_package_root(self):
+        original_cwd = os.getcwd()
+        try:
+            os.chdir(ROOT)
+            self.assertEqual(pkg._source_directory(), '.')
+            with tempfile.TemporaryDirectory() as tmp:
+                os.chdir(tmp)
+                source_root = pkg._source_directory()
+                self.assertFalse(os.path.isabs(source_root))
+                self.assertTrue(os.path.isfile(os.path.join(source_root, 'WAPT', 'control')))
+        finally:
+            os.chdir(original_cwd)
+
     def test_offline_updater_requires_expected_archive_hash(self):
         with tempfile.TemporaryDirectory() as tmp:
             archive = Path(tmp, 'archive.zip')