Add certificate policy of type any policy id

Add a function for getting the certificate policy. Currently only
"Any Policy" is supported.
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index a8e7523..1b7ea78 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -116,6 +116,7 @@
 add_test_suite(memory_buffer_alloc)
 add_test_suite(mpi)
 add_test_suite(nist_kw)
+add_test_suite(oid)
 add_test_suite(pem)
 add_test_suite(pkcs1_v15)
 add_test_suite(pkcs1_v21)
diff --git a/tests/suites/test_suite_oid.data b/tests/suites/test_suite_oid.data
new file mode 100644
index 0000000..759a010
--- /dev/null
+++ b/tests/suites/test_suite_oid.data
@@ -0,0 +1,8 @@
+OID get Any Policy certificate policy
+oid_get_certificate_policies:"551D2000":"Any Policy"
+
+OID get certificate policy invalid oid
+oid_get_certificate_policies:"5533445566":""
+
+OID get certificate policy wrong oid - id-ce-authorityKeyIdentifier
+oid_get_certificate_policies:"551D23":""
diff --git a/tests/suites/test_suite_oid.function b/tests/suites/test_suite_oid.function
new file mode 100644
index 0000000..e95e48d
--- /dev/null
+++ b/tests/suites/test_suite_oid.function
@@ -0,0 +1,34 @@
+/* BEGIN_HEADER */
+#include "mbedtls/oid.h"
+#include "mbedtls/asn1.h"
+#include "mbedtls/asn1write.h"
+#include "string.h"
+/* END_HEADER */
+
+/* BEGIN_DEPENDENCIES
+ * depends_on:MBEDTLS_OID_C
+ * END_DEPENDENCIES
+ */
+
+/* BEGIN_CASE depends_on:MBEDTLS_ASN1_WRITE_C*/
+void oid_get_certificate_policies( data_t * oid, char * result_str )
+{
+    mbedtls_asn1_buf asn1_buf = { 0, 0, NULL };
+    int ret;
+    const char *desc;
+
+    asn1_buf.tag = MBEDTLS_ASN1_OID;
+    asn1_buf.p = oid->x;
+    asn1_buf.len = oid->len;
+
+    ret = mbedtls_oid_get_certificate_policies( &asn1_buf, &desc );
+    if( strlen( result_str ) == 0 )
+    {
+        TEST_ASSERT( ret == MBEDTLS_ERR_OID_NOT_FOUND );
+    }
+    else
+    {
+        TEST_ASSERT( strcmp( ( char* )desc, result_str ) == 0 );
+    }
+}
+/* END_CASE */