diff --git a/runtime/doc/eval.txt b/runtime/doc/eval.txt
index 74c3d1c..3c0a1ae 100644
--- a/runtime/doc/eval.txt
+++ b/runtime/doc/eval.txt
@@ -2861,6 +2861,7 @@
 test_null_blob()		Blob	null value for testing
 test_null_channel()		Channel	null value for testing
 test_null_dict()		Dict	null value for testing
+test_null_function()		Funcref	null value for testing
 test_null_job()			Job	null value for testing
 test_null_list()		List	null value for testing
 test_null_partial()		Funcref	null value for testing
diff --git a/runtime/doc/testing.txt b/runtime/doc/testing.txt
index 82dc77e..458aa7c 100644
--- a/runtime/doc/testing.txt
+++ b/runtime/doc/testing.txt
@@ -106,6 +106,10 @@
 		Return a |Dict| that is null. Only useful for testing.
 
 
+test_null_function()					*test_null_function()*
+		Return a |FuncRef| that is null. Only useful for testing.
+
+
 test_null_job()						*test_null_job()*
 		Return a |Job| that is null. Only useful for testing.
 		{only available when compiled with the +job feature}