add fuzzing of resolver

based on the "random test" at the end of the regular resolver tests.

Signed-off-by: Steffen Jaeckel <jaeckel-floss@eyet-services.de>

tests/test_fuzz_parser.c

@@ -0,0 +1,49 @@
+#include <stdlib.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+
+#include "strophe.h"
+#include "parser.h"
+
+void xmpp_initialize(void);
+
+void cbtest_handle_start(char *name, char **attrs, void *userdata)
+{
+    (void)name;
+    (void)attrs;
+    (void)userdata;
+}
+
+void cbtest_handle_end(char *name, void *userdata)
+{
+    (void)name;
+    (void)userdata;
+}
+
+void cbtest_handle_stanza(xmpp_stanza_t *stanza, void *userdata)
+{
+    (void)stanza;
+    (void)userdata;
+}
+
+int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size)
+{
+    xmpp_ctx_t *ctx;
+    parser_t *parser;
+
+    char *dup = malloc(Size);
+    memcpy(dup, Data, Size);
+
+    ctx = xmpp_ctx_new(NULL, NULL);
+    parser = parser_new(ctx, cbtest_handle_start, cbtest_handle_end,
+                        cbtest_handle_stanza, NULL);
+
+    parser_feed(parser, dup, Size);
+
+    free(dup);
+    parser_free(parser);
+    xmpp_ctx_free(ctx);
+
+    return 0;
+}