[PATCH v3 4/4] perf test: Update test for --for-each-cgroup option

[Namhyung Kim]

To simply check the number of output lines with and without the option.

Before this series, it failed like below:

  $ perf test -v 125
  125: perf stat --bpf-counters --for-each-cgroup test:
  ---- start ----
  test child forked, pid 1941516
  Normal output has 22 lines, but it now has 54
  ---- end(-1) ----
  125: perf stat --bpf-counters --for-each-cgroup test         : FAILED!

Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx>
---
v3 changes)
 * use default events and metrics  (Sashiko)
 * update the commit description

 tools/perf/tests/shell/stat_bpf_counters_cgrp.sh | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/tools/perf/tests/shell/stat_bpf_counters_cgrp.sh b/tools/perf/tests/shell/stat_bpf_counters_cgrp.sh
index ff2e06c408bc6be1..febe3af0644157f3 100755
--- a/tools/perf/tests/shell/stat_bpf_counters_cgrp.sh
+++ b/tools/perf/tests/shell/stat_bpf_counters_cgrp.sh
@@ -58,9 +58,24 @@ check_system_wide_counted()
 	fi
 }
 
+# Missing flags in evlist__clone() resulted in different output.
+# Just check the number of output lines for simple verification.
+check_evlist_expand()
+{
+	normal_output=$(perf stat -a -x, true 2>&1 | wc -l)
+	expand_output=$(perf stat -a -x, --bpf-counters --for-each-cgroup / true 2>&1 | wc -l)
+	if [ "${normal_output}" != "${expand_output}" ]; then
+		if [ "${verbose}" = "1" ]; then
+			echo "Normal output has ${normal_output} lines, but it now has ${expand_output}"
+		fi
+		exit 1
+	fi
+}
+
 check_bpf_counter
 find_cgroups
 
 check_system_wide_counted
+check_evlist_expand
 
 exit 0
-- 
2.55.0.795.g602f6c329a-goog