Ensure mbedtls_sha3_finish zeroizes the context

Signed-off-by: Dave Rodgman <dave.rodgman@arm.com>
diff --git a/tests/suites/test_suite_shax.function b/tests/suites/test_suite_shax.function
index 7dd9166..629e281 100644
--- a/tests/suites/test_suite_shax.function
+++ b/tests/suites/test_suite_shax.function
@@ -176,9 +176,12 @@
     TEST_EQUAL(mbedtls_sha3_starts(&ctx, MBEDTLS_SHA3_NONE), MBEDTLS_ERR_SHA3_BAD_INPUT_DATA);
 
     TEST_EQUAL(mbedtls_sha3_starts(&ctx, MBEDTLS_SHA3_256), 0);
-
     TEST_EQUAL(mbedtls_sha3_finish(&ctx, output, 0), MBEDTLS_ERR_SHA3_BAD_INPUT_DATA);
+
+    TEST_EQUAL(mbedtls_sha3_starts(&ctx, MBEDTLS_SHA3_256), 0);
     TEST_EQUAL(mbedtls_sha3_finish(&ctx, output, 31), MBEDTLS_ERR_SHA3_BAD_INPUT_DATA);
+
+    TEST_EQUAL(mbedtls_sha3_starts(&ctx, MBEDTLS_SHA3_256), 0);
     TEST_EQUAL(mbedtls_sha3_finish(&ctx, output, 32), 0);
 
 exit: