diff --git a/src/testdir/test_writefile.in b/src/testdir/test_writefile.in
new file mode 100644
index 0000000..f2dc7d5
--- /dev/null
+++ b/src/testdir/test_writefile.in
@@ -0,0 +1,18 @@
+Tests for writefile()
+
+STARTTEST
+:source small.vim
+:%delete _
+:let f = tempname()
+:call writefile(["over","written"], f, "b")
+:call writefile(["hello","world"], f, "b")
+:call writefile(["!", "good"], f, "a")
+:call writefile(["morning"], f, "ab")
+:call writefile(["", "vimmers"], f, "ab")
+:bwipeout!
+:$put =readfile(f)
+:1 delete _
+:w! test.out
+:qa!
+ENDTEST
+
diff --git a/src/testdir/test_writefile.ok b/src/testdir/test_writefile.ok
new file mode 100644
index 0000000..dfb6a2b
--- /dev/null
+++ b/src/testdir/test_writefile.ok
@@ -0,0 +1,5 @@
+hello
+world!
+good
+morning
+vimmers