[PATCH v2 2/5] p0008-abbrev.sh: Test find_unique_abbrev() perf

[Derrick Stolee <dstolee@microsoft.com>]

Create helper program test-abbrev to compute the minimum length of a
disambiguating short-sha for an input list of object ids.

Perf test p0008-abbrev.sh runs test-abbrev for 100,000 object ids. For
test 0008.1, these objects exist. For test 0008.2 these objects do not
exist in the repo (with high probability). For each test, use `sort -R`
to (deterministically) shuffle the sample of object ids to not check
abbreviations in lexicographic order.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
---
 Makefile               |  1 +
 t/helper/.gitignore    |  1 +
 t/helper/test-abbrev.c | 19 +++++++++++++++++++
 t/perf/p0008-abbrev.sh | 22 ++++++++++++++++++++++
 4 files changed, 43 insertions(+)
 create mode 100644 t/helper/test-abbrev.c
 create mode 100755 t/perf/p0008-abbrev.sh

diff --git a/Makefile b/Makefile
index af94b655a..75835c7c0 100644
--- a/Makefile
+++ b/Makefile
@@ -633,6 +633,7 @@ X =
 
 PROGRAMS += $(patsubst %.o,git-%$X,$(PROGRAM_OBJS))
 
+TEST_PROGRAMS_NEED_X += test-abbrev
 TEST_PROGRAMS_NEED_X += test-chmtime
 TEST_PROGRAMS_NEED_X += test-ctype
 TEST_PROGRAMS_NEED_X += test-config
diff --git a/t/helper/.gitignore b/t/helper/.gitignore
index 9dd1c9f3c..ab9df8369 100644
--- a/t/helper/.gitignore
+++ b/t/helper/.gitignore
@@ -1,3 +1,4 @@
+/test-abbrev
 /test-chmtime
 /test-ctype
 /test-config
diff --git a/t/helper/test-abbrev.c b/t/helper/test-abbrev.c
new file mode 100644
index 000000000..6866896eb
--- /dev/null
+++ b/t/helper/test-abbrev.c
@@ -0,0 +1,19 @@
+#include "cache.h"
+#include <stdio.h>
+
+int cmd_main(int ac, const char **av)
+{
+	struct object_id oid;
+	char hex[GIT_MAX_HEXSZ + 2];
+	const char *end;
+
+	setup_git_directory();
+
+	while (fgets(hex, GIT_MAX_HEXSZ + 2, stdin)) {
+		hex[GIT_MAX_HEXSZ] = 0;
+		if (!parse_oid_hex(hex, &oid, &end))
+			find_unique_abbrev(oid.hash, MINIMUM_ABBREV);
+	}
+
+	exit(0);
+}
diff --git a/t/perf/p0008-abbrev.sh b/t/perf/p0008-abbrev.sh
new file mode 100755
index 000000000..ba25e7824
--- /dev/null
+++ b/t/perf/p0008-abbrev.sh
@@ -0,0 +1,22 @@
+#!/bin/bash
+
+test_description='Test object disambiguation through abbreviations'
+. ./perf-lib.sh
+
+test_perf_large_repo
+
+test-list-objects 100000 | sort -R > objs.txt
+
+test_perf 'find_unique_abbrev() for existing objects' '
+	test-abbrev < objs.txt
+'
+
+test-list-objects 100000 --missing | sort -R > objs.txt
+
+test_perf 'find_unique_abbrev() for missing objects' '
+	test-abbrev < objs.txt
+'
+
+rm objs.txt
+
+test_done
-- 
2.14.1.538.g56ec8fc98.dirty