perf test: Add a test case for hists__{match,link}

As they are used from diff and event group report, add a test case to
verify their behaviors.

In this test I made a fake machine and two evsel.  Each evsel got 10
samples (so hist entries) - 5 are common and the rests are not.  So
after hists__match() both of them will have 5 entries with pair set.

And the second evsel has a collapsed entry so that the total number is 9
- I made it in order to simulate more realistic case.  Thus after
hists__link the first entry will have 14 entries - 5 are common (w/
pair), 5 are unmatch (w/o pair) and 4 are dummy (w/ pair).  And the
second entry will have 9 entries all have its pair.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1355128197-18193-5-git-send-email-namhyung@kernel.org
[ committer note: fixed up clashes with cset that moved methods to machine.h ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/Makefile

@@ -487,6 +487,7 @@ LIB_OBJS += $(OUTPUT)tests/rdpmc.o
 LIB_OBJS += $(OUTPUT)tests/evsel-roundtrip-name.o
 LIB_OBJS += $(OUTPUT)tests/evsel-tp-sched.o
 LIB_OBJS += $(OUTPUT)tests/pmu.o
+LIB_OBJS += $(OUTPUT)tests/hists_link.o
 
 BUILTIN_OBJS += $(OUTPUT)builtin-annotate.o
 BUILTIN_OBJS += $(OUTPUT)builtin-bench.o

tools/perf/tests/builtin-test.c

@@ -68,6 +68,10 @@ static struct test {
 		.desc = "struct perf_event_attr setup",
 		.func = test__attr,
 	},
+	{
+		.desc = "Test matching and linking mutliple hists",
+		.func = test__hists_link,
+	},
 	{
 		.func = NULL,
 	},

tools/perf/tests/tests.h

@@ -15,5 +15,6 @@ int test__pmu(void);
 int test__attr(void);
 int test__dso_data(void);
 int test__parse_events(void);
+int test__hists_link(void);
 
 #endif /* TESTS_H */