sandbox: Add a test for disabling CONFIG_CMDLINE

Now that everything is working, add a test to make sure that this
builds correctly.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>
diff --git a/test/py/tests/test_sandbox_opts.py b/test/py/tests/test_sandbox_opts.py
new file mode 100644
index 0000000..91790b3
--- /dev/null
+++ b/test/py/tests/test_sandbox_opts.py
@@ -0,0 +1,20 @@
+# SPDX-License-Identifier: GPL-2.0
+# Copyright 2022 Google LLC
+# Written by Simon Glass <sjg@chromium.org>
+
+import pytest
+
+import u_boot_utils as util
+
+# This is needed for Azure, since the default '..' directory is not writeable
+TMPDIR = '/tmp/test_cmdline'
+
+@pytest.mark.slow
+@pytest.mark.boardspec('sandbox')
+def test_sandbox_cmdline(u_boot_console):
+    """Test building sandbox without CONFIG_CMDLINE"""
+    cons = u_boot_console
+
+    out = util.run_and_log(
+        cons, ['./tools/buildman/buildman', '-m', '--board', 'sandbox',
+               '-a', '~CMDLINE', '-o', TMPDIR])