diff --git a/src/evalfunc.c b/src/evalfunc.c
index d8e88e5..247d2ea 100644
--- a/src/evalfunc.c
+++ b/src/evalfunc.c
@@ -419,7 +419,7 @@
     {"asin",		1, 1, FEARG_1,	  ret_float,	FLOAT_FUNC(f_asin)},
     {"assert_beeps",	1, 2, FEARG_1,	  ret_number,	f_assert_beeps},
     {"assert_equal",	2, 3, FEARG_2,	  ret_number,	f_assert_equal},
-    {"assert_equalfile", 2, 2, FEARG_1,	  ret_number,	f_assert_equalfile},
+    {"assert_equalfile", 2, 3, FEARG_1,	  ret_number,	f_assert_equalfile},
     {"assert_exception", 1, 2, 0,	  ret_number,	f_assert_exception},
     {"assert_fails",	1, 3, FEARG_1,	  ret_number,	f_assert_fails},
     {"assert_false",	1, 2, FEARG_1,	  ret_number,	f_assert_false},
diff --git a/src/testdir/test_assert.vim b/src/testdir/test_assert.vim
index 762f12f..5037d87 100644
--- a/src/testdir/test_assert.vim
+++ b/src/testdir/test_assert.vim
@@ -81,6 +81,10 @@
   call assert_match("difference at byte 4", v:errors[0])
   call remove(v:errors, 0)
 
+  call assert_equal(1, assert_equalfile('Xone', 'Xtwo', 'a message'))
+  call assert_match("a message: difference at byte 4", v:errors[0])
+  call remove(v:errors, 0)
+
   call delete('Xone')
   call delete('Xtwo')
 endfunc
diff --git a/src/testing.c b/src/testing.c
index 604d39b..fa8cc42 100644
--- a/src/testing.c
+++ b/src/testing.c
@@ -362,6 +362,15 @@
     if (IObuff[0] != NUL)
     {
 	prepare_assert_error(&ga);
+	if (argvars[2].v_type != VAR_UNKNOWN)
+	{
+	    char_u	numbuf[NUMBUFLEN];
+	    char_u	*tofree;
+
+	    ga_concat(&ga, echo_string(&argvars[2], &tofree, numbuf, 0));
+	    vim_free(tofree);
+	    ga_concat(&ga, (char_u *)": ");
+	}
 	ga_concat(&ga, IObuff);
 	assert_error(&ga);
 	ga_clear(&ga);
@@ -371,7 +380,7 @@
 }
 
 /*
- * "assert_equalfile(fname-one, fname-two)" function
+ * "assert_equalfile(fname-one, fname-two[, msg])" function
  */
     void
 f_assert_equalfile(typval_T *argvars, typval_T *rettv)
diff --git a/src/version.c b/src/version.c
index a241fa0..fc6d897 100644
--- a/src/version.c
+++ b/src/version.c
@@ -747,6 +747,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    893,
+/**/
     892,
 /**/
     891,