Add sim65 tests

sw/tests/test_main.c

@@ -0,0 +1,10 @@
+#include <stdio.h>
+#include <spi.h>
+
+int main(void)
+{
+    printf("Starting spi_write_byte test...\n");
+    spi_write_byte(0xa5);
+    printf("Done!\n");
+    return 0;
+}