--- a/tests/test-add.t	Fri Mar 09 15:53:41 2018 +0100
+++ b/tests/test-add.t	Sat Mar 10 12:33:19 2018 +0530
@@ -256,3 +256,19 @@
 #endif
 
   $ cd ..
+
+test --dry-run mode in forget
+
+  $ hg init testdir_forget
+  $ cd testdir_forget
+  $ echo foo > foo
+  $ hg add foo
+  $ hg commit -m "foo"
+  $ hg forget foo --dry-run -v
+  removing foo
+  $ hg diff
+  $ hg forget not_exist -n
+  not_exist: $ENOENT$
+  [1]
+
+  $ cd ..