test: spl: Add a test for the SPI load method

Add test for the SPI load method. This one is pretty straightforward. We
can't enable FIT_EXTERNAL with LOAD_FIT_FULL because spl_spi_load_image
doesn't know the total image size and has to guess from fdt_totalsize. This
doesn't include external data, so loading it will fail.

Signed-off-by: Sean Anderson <seanga2@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/test/image/spl_load_spi.c b/test/image/spl_load_spi.c
new file mode 100644
index 0000000..8f9b6e0
--- /dev/null
+++ b/test/image/spl_load_spi.c
@@ -0,0 +1,41 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2023 Sean Anderson <seanga2@gmail.com>
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <spi_flash.h>
+#include <spl.h>
+#include <test/spl.h>
+#include <test/ut.h>
+
+static int spl_test_spi_write_image(struct unit_test_state *uts, void *img,
+				    size_t img_size)
+{
+	struct spi_flash *flash;
+
+	flash = spi_flash_probe(spl_spi_boot_bus(), spl_spi_boot_cs(),
+				CONFIG_SF_DEFAULT_SPEED,
+				CONFIG_SF_DEFAULT_MODE);
+	ut_assertnonnull(flash);
+	ut_assertok(spi_flash_write(flash, spl_spi_get_uboot_offs(flash),
+				    img_size, img));
+
+	return 0;
+}
+
+static int spl_test_spi(struct unit_test_state *uts, const char *test_name,
+			enum spl_test_image type)
+{
+	return do_spl_test_load(uts, test_name, type,
+				SPL_LOAD_IMAGE_GET(1, BOOT_DEVICE_SPI,
+						   spl_spi_load_image),
+				spl_test_spi_write_image);
+}
+SPL_IMG_TEST(spl_test_spi, LEGACY, DM_FLAGS);
+SPL_IMG_TEST(spl_test_spi, IMX8, DM_FLAGS);
+SPL_IMG_TEST(spl_test_spi, FIT_INTERNAL, DM_FLAGS);
+#if !IS_ENABLED(CONFIG_SPL_LOAD_FIT_FULL)
+SPL_IMG_TEST(spl_test_spi, FIT_EXTERNAL, DM_FLAGS);
+#endif