diff --git a/src/testdir/test_partial.vim b/src/testdir/test_partial.vim
index 5b273db..2fad7b2 100644
--- a/src/testdir/test_partial.vim
+++ b/src/testdir/test_partial.vim
@@ -194,6 +194,8 @@
   call assert_equal("function('MyFunc', {'one': 1})", string(F))
   let F = function('MyFunc', ['foo'], d)
   call assert_equal("function('MyFunc', ['foo'], {'one': 1})", string(F))
+  call assert_equal("function('')", string(test_null_function()))
+  call assert_equal("function('')", string(test_null_partial()))
 endfunc
 
 func Test_func_unref()