diff --git a/runtests.fs b/runtests.fs
index addc706..cb89eb4 100644
--- a/runtests.fs
+++ b/runtests.fs
@@ -11,6 +11,7 @@ include lib/tester.fs
 include test/core.fs
 include test/utilities.fs
 include test/coreexttest.fs
+include test/fileio.fs
 
 include test/export.fs
 include lib/string.fs
diff --git a/test/fileio-test0.txt b/test/fileio-test0.txt
new file mode 100644
index 0000000..72d007b
--- /dev/null
+++ b/test/fileio-test0.txt
@@ -0,0 +1 @@
+ABCDEFGHIJKLMNOPQRSTUVWXYZ
diff --git a/test/fileio.fs b/test/fileio.fs
new file mode 100644
index 0000000..d6af3b1
--- /dev/null
+++ b/test/fileio.fs
@@ -0,0 +1,15 @@
+\ planckforth -
+\ Copyright (C) 2021 nineties
+
+testing file I/O
+
+T{
+    s" test/fileio-test0.txt" R/O open-file throw
+    constant FILE0 ->
+}T
+T{ 32 allocate throw constant BUF -> }T
+T{ BUF 32 FILE0 read-file throw -> 27 }T
+T{ s" ABCDEFGHIJKLMNOPQRSTUVWXYZ
+" BUF 27 strneq -> true }T
+T{ FILE0 close-file throw -> }T
+T{ BUF free -> }T