diff --git a/behave/features/rdiff.feature b/behave/features/rdiff.feature
new file mode 100644
index 00000000..29a55857
--- /dev/null
+++ b/behave/features/rdiff.feature
@@ -0,0 +1,26 @@
+Feature: `osc rdiff` command
+
+
+# common steps for all scenarios
+Background:
+   Given I set working directory to "{context.osc.temp}"
+
+
+Scenario: Run `osc rdiff <project>/<package> <target-project>/<target-package>`
+    When I execute osc with args "rdiff test:factory/test-pkgA test:factory/test-pkgA"
+    Then the exit code is 0
+
+
+Scenario: Run `osc rdiff <project>/<package> <target-project>`
+    When I execute osc with args "rdiff test:factory/test-pkgA test:factory"
+    Then the exit code is 0
+
+
+Scenario: Run `osc rdiff <project>/<package>`
+    When I execute osc with args "rdiff test:factory/test-pkgA"
+    Then the exit code is 0
+
+
+Scenario: Run `osc rdiff <project>/<package> --change`
+    When I execute osc with args "rdiff test:factory/test-pkgA --change=1"
+    Then the exit code is 0
diff --git a/osc/commandline.py b/osc/commandline.py
index a57adcb2..29f1e017 100644
--- a/osc/commandline.py
+++ b/osc/commandline.py
@@ -4200,6 +4200,9 @@ Please submit there instead, or use --nodevelproject to force direct submission.
         )
         ensure_no_remaining_args(args)
 
+        if not new_project:
+            new_project = old_project
+
         if not new_package:
             new_package = old_package