Improve testing of md/PSA alg identifier macro conversions

Signed-off-by: Dave Rodgman <dave.rodgman@arm.com>
diff --git a/tests/suites/test_suite_md.function b/tests/suites/test_suite_md.function
index ac9516a..2768707 100644
--- a/tests/suites/test_suite_md.function
+++ b/tests/suites/test_suite_md.function
@@ -28,6 +28,11 @@
         TEST_EQUAL(0, mbedtls_md_starts(&ctx));
         TEST_EQUAL(0, mbedtls_md_finish(&ctx, out));
         mbedtls_md_free(&ctx);
+
+        /* Ensure that we can convert to and from a psa_algorithm_t */
+        psa_algorithm_t p = mbedtls_md_psa_alg_from_type(*md_type_ptr);
+        TEST_ASSERT(p != PSA_ALG_NONE);
+        TEST_EQUAL(*md_type_ptr, mbedtls_md_type_from_psa_alg(p));
     }
 
 exit: