Move mbedtls_oid_get_numeric_string unit tests to test_suite_x509parse

This commit moves all related mbedtls_oid_get_numeric_string unit tests
from test_suite_oid to test_suite_x509parse.

Signed-off-by: Sam Berry <sam.berry@arm.com>
diff --git a/tests/suites/test_suite_x509parse.function b/tests/suites/test_suite_x509parse.function
index 9fc0e55..66a7c8d 100644
--- a/tests/suites/test_suite_x509parse.function
+++ b/tests/suites/test_suite_x509parse.function
@@ -10,6 +10,8 @@
 #include "mbedtls/base64.h"
 #include "mbedtls/error.h"
 #include "mbedtls/pk.h"
+#include "mbedtls/asn1.h"
+#include "mbedtls/asn1write.h"
 #include "string.h"
 
 #if MBEDTLS_X509_MAX_INTERMEDIATE_CA > 19
@@ -1747,3 +1749,27 @@
     mbedtls_x509_crt_free(&crt);
 }
 /* END_CASE */
+
+/* BEGIN_CASE depends_on:MBEDTLS_x509_USE_C */
+void oid_get_numeric_string(data_t *oid, int error_ret, char *result_str)
+{
+    char buf[256];
+    mbedtls_asn1_buf input_oid = { 0, 0, NULL };
+    int ret;
+
+    input_oid.tag = MBEDTLS_ASN1_OID;
+    /* Test that an empty OID is not dereferenced */
+    input_oid.p = oid->len ? oid->x : (void *) 1;
+    input_oid.len = oid->len;
+
+    ret = mbedtls_oid_get_numeric_string(buf, sizeof(buf), &input_oid);
+
+    if (error_ret == 0) {
+        TEST_EQUAL(ret, strlen(result_str));
+        TEST_ASSERT(ret >= 3);
+        TEST_EQUAL(strcmp(buf, result_str), 0);
+    } else {
+        TEST_EQUAL(ret, error_ret);
+    }
+}
+/* END_CASE */