Add a test for calloc zeroization

Signed-off-by: Andrzej Kurek <andrzej.kurek@arm.com>
diff --git a/tests/suites/test_suite_platform.function b/tests/suites/test_suite_platform.function
index 61681b8..82c656d 100644
--- a/tests/suites/test_suite_platform.function
+++ b/tests/suites/test_suite_platform.function
@@ -120,3 +120,17 @@
     goto exit;
 }
 /* END_CASE */
+
+/* BEGIN_CASE */
+void check_mbedtls_calloc_zeroization()
+{
+    unsigned int buf_size = 256;
+    unsigned char *buf;
+    buf = mbedtls_calloc(buf_size, sizeof(unsigned char));
+    for (unsigned int i = 0; i < buf_size; i++) {
+        TEST_EQUAL(buf[i], 0);
+    }
+exit:
+    mbedtls_free(buf);
+}
+/* END_CASE */
\ No newline at end of file