diff --git a/tests/suites/test_suite_x509write.data b/tests/suites/test_suite_x509write.data
index 22d338c..0c300d5 100644
--- a/tests/suites/test_suite_x509write.data
+++ b/tests/suites/test_suite_x509write.data
@@ -37,3 +37,7 @@
 Public key write check EC
 depends_on:POLARSSL_ECP_C:POLARSSL_BASE64_C
 x509_pubkey_check:"data_files/ec_pub.pem"
+
+Private key write check RSA
+depends_on:POLARSSL_RSA_C:POLARSSL_BASE64_C
+x509_key_check:"data_files/server1.key"
diff --git a/tests/suites/test_suite_x509write.function b/tests/suites/test_suite_x509write.function
index 09dfff8..1393103 100644
--- a/tests/suites/test_suite_x509write.function
+++ b/tests/suites/test_suite_x509write.function
@@ -153,3 +153,32 @@
     pk_free( &key );
 }
 /* END_CASE */
+
+/* BEGIN_CASE */
+void x509_key_check( char *key_file )
+{
+    pk_context key;
+    unsigned char buf[5000];
+    unsigned char check_buf[5000];
+    int ret;
+    FILE *f;
+
+    memset( buf, 0, sizeof( buf ) );
+    memset( check_buf, 0, sizeof( check_buf ) );
+
+    pk_init( &key );
+    TEST_ASSERT( x509parse_keyfile( &key, key_file, NULL ) == 0 );
+
+    ret = x509write_key_pem( pk_rsa( key ), buf, sizeof( buf ) - 1);
+    TEST_ASSERT( ret >= 0 );
+
+    f = fopen( key_file, "r" );
+    TEST_ASSERT( f != NULL );
+    fread( check_buf, 1, sizeof( check_buf ) - 1, f );
+    fclose( f );
+
+    TEST_ASSERT( strncmp( (char *) buf, (char *) check_buf, sizeof( buf ) ) == 0 );
+
+    pk_free( &key );
+}
+/* END_CASE */