test: Add tests for the extcon

Provide tests to the simple extcon device.

Signed-off-by: Svyatoslav Ryhel <clamor95@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/extcon/extcon-sandbox.c b/drivers/extcon/extcon-sandbox.c
new file mode 100644
index 0000000..ab6a6c1
--- /dev/null
+++ b/drivers/extcon/extcon-sandbox.c
@@ -0,0 +1,17 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (c) 2022 Svyatoslav Ryhel <clamor95@gmail.com>
+ */
+
+#include <dm.h>
+
+static const struct udevice_id sandbox_extcon_ids[] = {
+	{ .compatible = "sandbox,extcon" },
+	{ /* sentinel */ }
+};
+
+U_BOOT_DRIVER(extcon_sandbox) = {
+	.name		= "extcon_sandbox",
+	.id		= UCLASS_EXTCON,
+	.of_match	= sandbox_extcon_ids,
+};