+ FILE *f;
+ /* Remove anything from prior partial run. */
+ unlink (BASE "file");
+
+ /* Read requires existing file. */
+ errno = 0;
+ ASSERT (fopen (BASE "file", "r") == NULL);
+ ASSERT (errno == ENOENT);
+
+ /* Write can create a file. */
+ f = fopen (BASE "file", "w");
+ ASSERT (f);
+ ASSERT (fclose (f) == 0);
+
+ /* Trailing slash is invalid on non-directory. */
+ errno = 0;
+ ASSERT (fopen (BASE "file/", "r") == NULL);
+ ASSERT (errno == ENOTDIR || errno == EISDIR || errno == EINVAL);
+
+ /* Cannot create a directory. */
+ errno = 0;