[PATCH 2/3] test-tool: add `getuid` subcommand

[Eric Sunshine <sunshine@sunshineco.com>]

It is difficult, if not impossible, for a test to obtain the user ID in
a portable fashion on all platforms and be guaranteed that it is the
same user ID Git itself sees when invoking getuid(). This is especially
true on Microsoft Windows for which getuid() in C code and $(id -u) in a
shell script may return entirely different values. Sidestep this problem
by adding a `getuid` subcommand to test-tool which is guaranteed to
provide tests with the same value as getuid() returns in Git code.

Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
---
 Makefile               | 1 +
 t/helper/test-getuid.c | 7 +++++++
 t/helper/test-tool.c   | 1 +
 t/helper/test-tool.h   | 1 +
 4 files changed, 10 insertions(+)
 create mode 100644 t/helper/test-getuid.c

diff --git a/Makefile b/Makefile
index c39b39bd7d..a5c38aad5e 100644
--- a/Makefile
+++ b/Makefile
@@ -703,6 +703,7 @@ TEST_BUILTINS_OBJS += test-dump-untracked-cache.o
 TEST_BUILTINS_OBJS += test-example-decorate.o
 TEST_BUILTINS_OBJS += test-genrandom.o
 TEST_BUILTINS_OBJS += test-genzeros.o
+TEST_BUILTINS_OBJS += test-getuid.o
 TEST_BUILTINS_OBJS += test-hash-speed.o
 TEST_BUILTINS_OBJS += test-hash.o
 TEST_BUILTINS_OBJS += test-hashmap.o
diff --git a/t/helper/test-getuid.c b/t/helper/test-getuid.c
new file mode 100644
index 0000000000..d741302461
--- /dev/null
+++ b/t/helper/test-getuid.c
@@ -0,0 +1,7 @@
+#include "test-tool.h"
+
+int cmd__getuid(int argc, const char **argv)
+{
+	printf("%d\n", getuid());
+	return 0;
+}
diff --git a/t/helper/test-tool.c b/t/helper/test-tool.c
index 432b49d948..ad5f681e68 100644
--- a/t/helper/test-tool.c
+++ b/t/helper/test-tool.c
@@ -31,6 +31,7 @@ static struct test_cmd cmds[] = {
 	{ "example-decorate", cmd__example_decorate },
 	{ "genrandom", cmd__genrandom },
 	{ "genzeros", cmd__genzeros },
+	{ "getuid", cmd__getuid },
 	{ "hashmap", cmd__hashmap },
 	{ "hash-speed", cmd__hash_speed },
 	{ "index-version", cmd__index_version },
diff --git a/t/helper/test-tool.h b/t/helper/test-tool.h
index 7c3281e071..765976e1eb 100644
--- a/t/helper/test-tool.h
+++ b/t/helper/test-tool.h
@@ -21,6 +21,7 @@ int cmd__dump_untracked_cache(int argc, const char **argv);
 int cmd__example_decorate(int argc, const char **argv);
 int cmd__genrandom(int argc, const char **argv);
 int cmd__genzeros(int argc, const char **argv);
+int cmd__getuid(int argc, const char **argv);
 int cmd__hashmap(int argc, const char **argv);
 int cmd__hash_speed(int argc, const char **argv);
 int cmd__index_version(int argc, const char **argv);
-- 
2.29.2.576.ga3fc446d84