test/py: add tests for the button commands

Adds tests for the button commands.

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Philippe Reynes <philippe.reynes@softathome.com>

test/py/tests/test_button.py

@@ -0,0 +1,19 @@
+# SPDX-License-Identifier: GPL-2.0+
+
+import pytest
+
+@pytest.mark.boardspec('sandbox')
+@pytest.mark.buildconfigspec('cmd_button')
+def test_button_exit_statuses(u_boot_console):
+    """Test that non-input button commands correctly return the command
+    success/failure status."""
+
+    expected_response = 'rc:0'
+    response = u_boot_console.run_command('button list; echo rc:$?')
+    assert(expected_response in response)
+    response = u_boot_console.run_command('button summer; echo rc:$?')
+    assert(expected_response in response)
+
+    expected_response = 'rc:1'
+    response = u_boot_console.run_command('button nonexistent-button; echo rc:$?')
+    assert(expected_response in response)