struct perf_evsel *evsel = perf_evlist__first(evlist);
 
        TEST_ASSERT_VAL("wrong number of entries", 1 == evlist->nr_entries);
+       TEST_ASSERT_VAL("wrong number of groups", 0 == evlist->nr_groups);
        TEST_ASSERT_VAL("wrong type", PERF_TYPE_TRACEPOINT == evsel->attr.type);
        TEST_ASSERT_VAL("wrong sample_type",
                PERF_TP_SAMPLE_TYPE == evsel->attr.sample_type);
        struct perf_evsel *evsel;
 
        TEST_ASSERT_VAL("wrong number of entries", evlist->nr_entries > 1);
+       TEST_ASSERT_VAL("wrong number of groups", 0 == evlist->nr_groups);
 
        list_for_each_entry(evsel, &evlist->entries, node) {
                TEST_ASSERT_VAL("wrong type",
        struct perf_evsel *evsel, *leader;
 
        TEST_ASSERT_VAL("wrong number of entries", 2 == evlist->nr_entries);
+       TEST_ASSERT_VAL("wrong number of groups", 1 == evlist->nr_groups);
 
        /* instructions:k */
        evsel = leader = perf_evlist__first(evlist);
        TEST_ASSERT_VAL("wrong exclude host", !evsel->attr.exclude_host);
        TEST_ASSERT_VAL("wrong precise_ip", !evsel->attr.precise_ip);
        TEST_ASSERT_VAL("wrong leader", perf_evsel__is_group_leader(evsel));
+       TEST_ASSERT_VAL("wrong nr_members", evsel->nr_members == 2);
+       TEST_ASSERT_VAL("wrong group_idx", perf_evsel__group_idx(evsel) == 0);
 
        /* cycles:upp */
        evsel = perf_evsel__next(evsel);
        TEST_ASSERT_VAL("wrong exclude host", !evsel->attr.exclude_host);
        TEST_ASSERT_VAL("wrong precise_ip", evsel->attr.precise_ip == 2);
        TEST_ASSERT_VAL("wrong leader", evsel->leader == leader);
+       TEST_ASSERT_VAL("wrong group_idx", perf_evsel__group_idx(evsel) == 1);
 
        return 0;
 }
        struct perf_evsel *evsel, *leader;
 
        TEST_ASSERT_VAL("wrong number of entries", 3 == evlist->nr_entries);
+       TEST_ASSERT_VAL("wrong number of groups", 1 == evlist->nr_groups);
 
        /* faults + :ku modifier */
        evsel = leader = perf_evlist__first(evlist);
        TEST_ASSERT_VAL("wrong exclude host", !evsel->attr.exclude_host);
        TEST_ASSERT_VAL("wrong precise_ip", !evsel->attr.precise_ip);
        TEST_ASSERT_VAL("wrong leader", perf_evsel__is_group_leader(evsel));
+       TEST_ASSERT_VAL("wrong nr_members", evsel->nr_members == 2);
+       TEST_ASSERT_VAL("wrong group_idx", perf_evsel__group_idx(evsel) == 0);
 
        /* cache-references + :u modifier */
        evsel = perf_evsel__next(evsel);
        TEST_ASSERT_VAL("wrong exclude host", !evsel->attr.exclude_host);
        TEST_ASSERT_VAL("wrong precise_ip", !evsel->attr.precise_ip);
        TEST_ASSERT_VAL("wrong leader", evsel->leader == leader);
+       TEST_ASSERT_VAL("wrong group_idx", perf_evsel__group_idx(evsel) == 1);
 
        /* cycles:k */
        evsel = perf_evsel__next(evsel);
        struct perf_evsel *evsel, *leader;
 
        TEST_ASSERT_VAL("wrong number of entries", 5 == evlist->nr_entries);
+       TEST_ASSERT_VAL("wrong number of groups", 2 == evlist->nr_groups);
 
        /* group1 syscalls:sys_enter_open:H */
        evsel = leader = perf_evlist__first(evlist);
        TEST_ASSERT_VAL("wrong leader", perf_evsel__is_group_leader(evsel));
        TEST_ASSERT_VAL("wrong group name",
                !strcmp(leader->group_name, "group1"));
+       TEST_ASSERT_VAL("wrong nr_members", evsel->nr_members == 2);
+       TEST_ASSERT_VAL("wrong group_idx", perf_evsel__group_idx(evsel) == 0);
 
        /* group1 cycles:kppp */
        evsel = perf_evsel__next(evsel);
        TEST_ASSERT_VAL("wrong precise_ip", evsel->attr.precise_ip == 3);
        TEST_ASSERT_VAL("wrong leader", evsel->leader == leader);
        TEST_ASSERT_VAL("wrong group name", !evsel->group_name);
+       TEST_ASSERT_VAL("wrong group_idx", perf_evsel__group_idx(evsel) == 1);
 
        /* group2 cycles + G modifier */
        evsel = leader = perf_evsel__next(evsel);
        TEST_ASSERT_VAL("wrong leader", perf_evsel__is_group_leader(evsel));
        TEST_ASSERT_VAL("wrong group name",
                !strcmp(leader->group_name, "group2"));
+       TEST_ASSERT_VAL("wrong nr_members", evsel->nr_members == 2);
+       TEST_ASSERT_VAL("wrong group_idx", perf_evsel__group_idx(evsel) == 0);
 
        /* group2 1:3 + G modifier */
        evsel = perf_evsel__next(evsel);
        TEST_ASSERT_VAL("wrong exclude host", evsel->attr.exclude_host);
        TEST_ASSERT_VAL("wrong precise_ip", !evsel->attr.precise_ip);
        TEST_ASSERT_VAL("wrong leader", evsel->leader == leader);
+       TEST_ASSERT_VAL("wrong group_idx", perf_evsel__group_idx(evsel) == 1);
 
        /* instructions:u */
        evsel = perf_evsel__next(evsel);
        struct perf_evsel *evsel, *leader;
 
        TEST_ASSERT_VAL("wrong number of entries", 2 == evlist->nr_entries);
+       TEST_ASSERT_VAL("wrong number of groups", 1 == evlist->nr_groups);
 
        /* cycles:u + p */
        evsel = leader = perf_evlist__first(evlist);
        TEST_ASSERT_VAL("wrong precise_ip", evsel->attr.precise_ip == 1);
        TEST_ASSERT_VAL("wrong group name", !evsel->group_name);
        TEST_ASSERT_VAL("wrong leader", perf_evsel__is_group_leader(evsel));
+       TEST_ASSERT_VAL("wrong nr_members", evsel->nr_members == 2);
+       TEST_ASSERT_VAL("wrong group_idx", perf_evsel__group_idx(evsel) == 0);
 
        /* instructions:kp + p */
        evsel = perf_evsel__next(evsel);
        TEST_ASSERT_VAL("wrong exclude host", !evsel->attr.exclude_host);
        TEST_ASSERT_VAL("wrong precise_ip", evsel->attr.precise_ip == 2);
        TEST_ASSERT_VAL("wrong leader", evsel->leader == leader);
+       TEST_ASSERT_VAL("wrong group_idx", perf_evsel__group_idx(evsel) == 1);
 
        return 0;
 }
        struct perf_evsel *evsel, *leader;
 
        TEST_ASSERT_VAL("wrong number of entries", 5 == evlist->nr_entries);
+       TEST_ASSERT_VAL("wrong number of groups", 2 == evlist->nr_groups);
 
        /* cycles + G */
        evsel = leader = perf_evlist__first(evlist);
        TEST_ASSERT_VAL("wrong precise_ip", !evsel->attr.precise_ip);
        TEST_ASSERT_VAL("wrong group name", !evsel->group_name);
        TEST_ASSERT_VAL("wrong leader", perf_evsel__is_group_leader(evsel));
+       TEST_ASSERT_VAL("wrong nr_members", evsel->nr_members == 2);
+       TEST_ASSERT_VAL("wrong group_idx", perf_evsel__group_idx(evsel) == 0);
 
        /* instructions + G */
        evsel = perf_evsel__next(evsel);
        TEST_ASSERT_VAL("wrong exclude host", evsel->attr.exclude_host);
        TEST_ASSERT_VAL("wrong precise_ip", !evsel->attr.precise_ip);
        TEST_ASSERT_VAL("wrong leader", evsel->leader == leader);
+       TEST_ASSERT_VAL("wrong group_idx", perf_evsel__group_idx(evsel) == 1);
 
        /* cycles:G */
        evsel = leader = perf_evsel__next(evsel);
        TEST_ASSERT_VAL("wrong precise_ip", !evsel->attr.precise_ip);
        TEST_ASSERT_VAL("wrong group name", !evsel->group_name);
        TEST_ASSERT_VAL("wrong leader", perf_evsel__is_group_leader(evsel));
+       TEST_ASSERT_VAL("wrong nr_members", evsel->nr_members == 2);
+       TEST_ASSERT_VAL("wrong group_idx", perf_evsel__group_idx(evsel) == 0);
 
        /* instructions:G */
        evsel = perf_evsel__next(evsel);
        TEST_ASSERT_VAL("wrong exclude host", evsel->attr.exclude_host);
        TEST_ASSERT_VAL("wrong precise_ip", !evsel->attr.precise_ip);
        TEST_ASSERT_VAL("wrong leader", evsel->leader == leader);
+       TEST_ASSERT_VAL("wrong group_idx", perf_evsel__group_idx(evsel) == 1);
 
        /* cycles */
        evsel = perf_evsel__next(evsel);