Add unit tests for struct filtering rules

And clean up whitespace

tests/check/filter.t.c

@@ -39,6 +39,7 @@ START_TEST(set_filter_rule_01)
 	opts_t *opts = opts_new();
 	conn_opts_t *conn_opts = conn_opts_new();
 
+	// ATTENTION: We cannot use const string like 's = "*"' here, because we modify s in filter_rule_set(), which gives signal 11
 	s = strdup("*");
 	rv = filter_rule_set(opts, conn_opts, "Divert", s, 0);
 	fail_unless(rv == 0, "failed to parse rule");

tests/check/main.t.c

@@ -67,6 +67,7 @@ main_suite(void)
 
 Suite * opts_suite(void);
 Suite * filter_suite(void);
+Suite * filter_struct_suite(void);
 Suite * dynbuf_suite(void);
 Suite * logbuf_suite(void);
 Suite * cert_suite(void);
@@ -94,6 +95,7 @@ main(UNUSED int argc, UNUSED char *argv[])
 	srunner_add_suite(sr, main_suite());
 	srunner_add_suite(sr, opts_suite());
 	srunner_add_suite(sr, filter_suite());
+	srunner_add_suite(sr, filter_struct_suite());
 	srunner_add_suite(sr, dynbuf_suite());
 	srunner_add_suite(sr, logbuf_suite());
 	srunner_add_suite(sr, cert_suite());