1 files changed, 22 insertions, 0 deletions

diff --git a/tests/userprog/read-zero.c b/tests/userprog/read-zero.c
new file mode 100644
index 0000000..e441817
--- /dev/null
+++ b/tests/userprog/read-zero.c
@@ -0,0 +1,22 @@
+/* Try a 0-byte read, which should return 0 without reading
+   anything. */
+
+#include <syscall.h>
+#include "tests/lib.h"
+#include "tests/main.h"
+
+void
+test_main (void) 
+{
+  int handle, byte_cnt;
+  char buf;
+
+  CHECK ((handle = open ("sample.txt")) > 1, "open \"sample.txt\"");
+
+  buf = 123;
+  byte_cnt = read (handle, &buf, 0);
+  if (byte_cnt != 0)
+    fail ("read() returned %d instead of 0", byte_cnt);
+  else if (buf != 123)
+    fail ("0-byte read() modified buffer");
+}