t/helper/test-bitmap.c: initial commit

Add a new 'bitmap' test-tool which can be used to list the commits that
have received bitmaps.

In theory, a determined tester could run 'git rev-list --test-bitmap
<commit>' to check if '<commit>' received a bitmap or not, since
'--test-bitmap' exits with a non-zero code when it can't find the
requested commit.

But this is a dubious behavior to rely on, since arguably 'git
rev-list' could continue its object walk outside of which commits are
covered by bitmaps.

This will be used to test the behavior of 'pack.preferBitmapTips', which
will be added in the following patch.

Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

4 files changed, 27 insertions, 0 deletions

diff --git a/Makefile b/Makefile
index 55c8035fa8..89b30495eb 100644
--- a/Makefile
+++ b/Makefile
@@ -693,6 +693,7 @@ X =
 PROGRAMS += $(patsubst %.o,git-%$X,$(PROGRAM_OBJS))
 
 TEST_BUILTINS_OBJS += test-advise.o
+TEST_BUILTINS_OBJS += test-bitmap.o
 TEST_BUILTINS_OBJS += test-bloom.o
 TEST_BUILTINS_OBJS += test-chmtime.o
 TEST_BUILTINS_OBJS += test-config.o
diff --git a/t/helper/test-bitmap.c b/t/helper/test-bitmap.c
new file mode 100644
index 0000000000..134a1e9d76
--- /dev/null
+++ b/t/helper/test-bitmap.c
@@ -0,0 +1,24 @@
+#include "test-tool.h"
+#include "cache.h"
+#include "pack-bitmap.h"
+
+static int bitmap_list_commits(void)
+{
+	return test_bitmap_commits(the_repository);
+}
+
+int cmd__bitmap(int argc, const char **argv)
+{
+	setup_git_directory();
+
+	if (argc != 2)
+		goto usage;
+
+	if (!strcmp(argv[1], "list-commits"))
+		return bitmap_list_commits();
+
+usage:
+	usage("\ttest-tool bitmap list-commits");
+
+	return -1;
+}
diff --git a/t/helper/test-tool.c b/t/helper/test-tool.c
index f97cd9f48a..a48bd44116 100644
--- a/t/helper/test-tool.c
+++ b/t/helper/test-tool.c
@@ -15,6 +15,7 @@ struct test_cmd {
 
 static struct test_cmd cmds[] = {
 	{ "advise", cmd__advise_if_enabled },
+	{ "bitmap", cmd__bitmap },
 	{ "bloom", cmd__bloom },
 	{ "chmtime", cmd__chmtime },
 	{ "config", cmd__config },
diff --git a/t/helper/test-tool.h b/t/helper/test-tool.h
index 28072c0ad5..563fe1b030 100644
--- a/t/helper/test-tool.h
+++ b/t/helper/test-tool.h
@@ -5,6 +5,7 @@
 #include "git-compat-util.h"
 
 int cmd__advise_if_enabled(int argc, const char **argv);
+int cmd__bitmap(int argc, const char **argv);
 int cmd__bloom(int argc, const char **argv);
 int cmd__chmtime(int argc, const char **argv);
 int cmd__config(int argc, const char **argv);