1 files changed, 26 insertions, 0 deletions
diff --git a/libraries/base/tests/IO/readFile001.hs b/libraries/base/tests/IO/readFile001.hs
new file mode 100644
index 0000000000..e4a2b34cb7
--- /dev/null
+++ b/libraries/base/tests/IO/readFile001.hs
@@ -0,0 +1,26 @@
+-- !!! readFile test
+
+import System.IO
+import System.IO.Error
+
+source   = "readFile001.hs"
+filename = "readFile001.out"
+
+main = do
+  s <- readFile source
+  h <- openFile filename WriteMode
+  hPutStrLn h s
+  hClose h
+  s <- readFile filename
+
+  -- This open should fail, because the readFile hasn't been forced
+  -- and the file is therefore still locked.
+  tryIOError (openFile filename WriteMode) >>= print
+
+  putStrLn s
+
+  -- should be able to open it for writing now, because we've forced the
+  -- whole file.
+  h <- openFile filename WriteMode
+
+  print h