Add test files

Author: hoodmane

test/fs/test_enotdir.c

@@ -0,0 +1,17 @@
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/stat.h>
+
+int main() {
+    {
+        int src_fd = open("file", O_CREAT | O_WRONLY, 0777);
+        close(src_fd);
+    }
+    {
+        int target_fd = mkdir("file/blah", 0777);
+        printf("target_fd: %d, errno: %d %s\n", target_fd, errno, strerror(errno));
+    }
+}

test/fs/test_enotdir.out

@@ -0,0 +1 @@
+target_fd: -1, errno: 54 Not a directory