diff --git a/.gitignore b/.gitignore
index e942a83b45b..6782f3cecac 100644
--- a/.gitignore
+++ b/.gitignore
@@ -59,7 +59,6 @@
 /git-difftool
 /git-difftool--helper
 /git-describe
-/git-env--helper
 /git-fast-export
 /git-fast-import
 /git-fetch
diff --git a/Makefile b/Makefile
index db447d07383..f2f342683c1 100644
--- a/Makefile
+++ b/Makefile
@@ -799,6 +799,7 @@ TEST_BUILTINS_OBJS += test-dump-fsmonitor.o
 TEST_BUILTINS_OBJS += test-dump-split-index.o
 TEST_BUILTINS_OBJS += test-dump-untracked-cache.o
 TEST_BUILTINS_OBJS += test-example-decorate.o
+TEST_BUILTINS_OBJS += test-env-helper.o
 TEST_BUILTINS_OBJS += test-fast-rebase.o
 TEST_BUILTINS_OBJS += test-fsmonitor-client.o
 TEST_BUILTINS_OBJS += test-genrandom.o
@@ -1231,7 +1232,6 @@ BUILTIN_OBJS += builtin/diff-index.o
 BUILTIN_OBJS += builtin/diff-tree.o
 BUILTIN_OBJS += builtin/diff.o
 BUILTIN_OBJS += builtin/difftool.o
-BUILTIN_OBJS += builtin/env--helper.o
 BUILTIN_OBJS += builtin/fast-export.o
 BUILTIN_OBJS += builtin/fast-import.o
 BUILTIN_OBJS += builtin/fetch-pack.o
diff --git a/git.c b/git.c
index 32a5be68a17..96b0a2837dc 100644
--- a/git.c
+++ b/git.c
@@ -507,7 +507,6 @@ static struct cmd_struct commands[] = {
 	{ "diff-index", cmd_diff_index, RUN_SETUP | NO_PARSEOPT },
 	{ "diff-tree", cmd_diff_tree, RUN_SETUP | NO_PARSEOPT },
 	{ "difftool", cmd_difftool, RUN_SETUP_GENTLY },
-	{ "env--helper", cmd_env__helper },
 	{ "fast-export", cmd_fast_export, RUN_SETUP },
 	{ "fast-import", cmd_fast_import, RUN_SETUP | NO_PARSEOPT },
 	{ "fetch", cmd_fetch, RUN_SETUP },
diff --git a/builtin/env--helper.c b/t/helper/test-env-helper.c
similarity index 71%
rename from builtin/env--helper.c
rename to t/helper/test-env-helper.c
index ea04c166364..66c88b8ff3d 100644
--- a/builtin/env--helper.c
+++ b/t/helper/test-env-helper.c
@@ -1,9 +1,9 @@
-#include "builtin.h"
+#include "test-tool.h"
 #include "config.h"
 #include "parse-options.h"
 
 static char const * const env__helper_usage[] = {
-	N_("git env--helper --type=[bool|ulong] <options> <env-var>"),
+	"test-tool env-helper --type=[bool|ulong] <options> <env-var>",
 	NULL
 };
 
@@ -24,12 +24,12 @@ static int option_parse_type(const struct option *opt, const char *arg,
 	else if (!strcmp(arg, "ulong"))
 		*cmdmode = ENV_HELPER_TYPE_ULONG;
 	else
-		die(_("unrecognized --type argument, %s"), arg);
+		die("unrecognized --type argument, %s", arg);
 
 	return 0;
 }
 
-int cmd_env__helper(int argc, const char **argv, const char *prefix)
+int cmd__env_helper(int argc, const char **argv)
 {
 	int exit_code = 0;
 	const char *env_variable = NULL;
@@ -39,17 +39,17 @@ int cmd_env__helper(int argc, const char **argv, const char *prefix)
 	unsigned long ret_ulong, default_ulong;
 	enum cmdmode cmdmode = 0;
 	struct option opts[] = {
-		OPT_CALLBACK_F(0, "type", &cmdmode, N_("type"),
-			       N_("value is given this type"), PARSE_OPT_NONEG,
+		OPT_CALLBACK_F(0, "type", &cmdmode, "type",
+			       "value is given this type", PARSE_OPT_NONEG,
 			       option_parse_type),
-		OPT_STRING(0, "default", &env_default, N_("value"),
-			   N_("default for git_env_*(...) to fall back on")),
+		OPT_STRING(0, "default", &env_default, "value",
+			   "default for git_env_*(...) to fall back on"),
 		OPT_BOOL(0, "exit-code", &exit_code,
-			 N_("be quiet only use git_env_*() value as exit code")),
+			 "be quiet only use git_env_*() value as exit code"),
 		OPT_END(),
 	};
 
-	argc = parse_options(argc, argv, prefix, opts, env__helper_usage,
+	argc = parse_options(argc, argv, NULL, opts, env__helper_usage,
 			     PARSE_OPT_KEEP_UNKNOWN_OPT);
 	if (env_default && !*env_default)
 		usage_with_options(env__helper_usage, opts);
@@ -64,7 +64,7 @@ int cmd_env__helper(int argc, const char **argv, const char *prefix)
 		if (env_default) {
 			default_int = git_parse_maybe_bool(env_default);
 			if (default_int == -1) {
-				error(_("option `--default' expects a boolean value with `--type=bool`, not `%s`"),
+				error("option `--default' expects a boolean value with `--type=bool`, not `%s`",
 				      env_default);
 				usage_with_options(env__helper_usage, opts);
 			}
@@ -79,7 +79,7 @@ int cmd_env__helper(int argc, const char **argv, const char *prefix)
 	case ENV_HELPER_TYPE_ULONG:
 		if (env_default) {
 			if (!git_parse_ulong(env_default, &default_ulong)) {
-				error(_("option `--default' expects an unsigned long value with `--type=ulong`, not `%s`"),
+				error("option `--default' expects an unsigned long value with `--type=ulong`, not `%s`",
 				      env_default);
 				usage_with_options(env__helper_usage, opts);
 			}
diff --git a/t/helper/test-tool.c b/t/helper/test-tool.c
index 7eb1a26a305..abe8a785eb6 100644
--- a/t/helper/test-tool.c
+++ b/t/helper/test-tool.c
@@ -28,6 +28,7 @@ static struct test_cmd cmds[] = {
 	{ "dump-fsmonitor", cmd__dump_fsmonitor },
 	{ "dump-split-index", cmd__dump_split_index },
 	{ "dump-untracked-cache", cmd__dump_untracked_cache },
+	{ "env-helper", cmd__env_helper },
 	{ "example-decorate", cmd__example_decorate },
 	{ "fast-rebase", cmd__fast_rebase },
 	{ "fsmonitor-client", cmd__fsmonitor_client },
diff --git a/t/helper/test-tool.h b/t/helper/test-tool.h
index 2e20a16eb82..ea2672436c9 100644
--- a/t/helper/test-tool.h
+++ b/t/helper/test-tool.h
@@ -22,6 +22,7 @@ int cmd__dump_fsmonitor(int argc, const char **argv);
 int cmd__dump_split_index(int argc, const char **argv);
 int cmd__dump_untracked_cache(int argc, const char **argv);
 int cmd__dump_reftable(int argc, const char **argv);
+int cmd__env_helper(int argc, const char **argv);
 int cmd__example_decorate(int argc, const char **argv);
 int cmd__fast_rebase(int argc, const char **argv);
 int cmd__fsmonitor_client(int argc, const char **argv);
diff --git a/t/t0017-env-helper.sh b/t/t0017-env-helper.sh
index 2e42fba9567..fc14ba091cb 100755
--- a/t/t0017-env-helper.sh
+++ b/t/t0017-env-helper.sh
@@ -1,87 +1,87 @@
 #!/bin/sh
 
-test_description='test env--helper'
+test_description='test test-tool env-helper'
 
 TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 
-test_expect_success 'env--helper usage' '
-	test_must_fail git env--helper &&
-	test_must_fail git env--helper --type=bool &&
-	test_must_fail git env--helper --type=ulong &&
-	test_must_fail git env--helper --type=bool &&
-	test_must_fail git env--helper --type=bool --default &&
-	test_must_fail git env--helper --type=bool --default= &&
-	test_must_fail git env--helper --defaultxyz
+test_expect_success 'test-tool env-helper usage' '
+	test_must_fail test-tool env-helper &&
+	test_must_fail test-tool env-helper --type=bool &&
+	test_must_fail test-tool env-helper --type=ulong &&
+	test_must_fail test-tool env-helper --type=bool &&
+	test_must_fail test-tool env-helper --type=bool --default &&
+	test_must_fail test-tool env-helper --type=bool --default= &&
+	test_must_fail test-tool env-helper --defaultxyz
 '
 
-test_expect_success 'env--helper bad default values' '
-	test_must_fail git env--helper --type=bool --default=1xyz MISSING &&
-	test_must_fail git env--helper --type=ulong --default=1xyz MISSING
+test_expect_success 'test-tool env-helper bad default values' '
+	test_must_fail test-tool env-helper --type=bool --default=1xyz MISSING &&
+	test_must_fail test-tool env-helper --type=ulong --default=1xyz MISSING
 '
 
-test_expect_success 'env--helper --type=bool' '
+test_expect_success 'test-tool env-helper --type=bool' '
 	# Test various --default bool values
 	echo true >expected &&
-	git env--helper --type=bool --default=1 MISSING >actual &&
+	test-tool env-helper --type=bool --default=1 MISSING >actual &&
 	test_cmp expected actual &&
-	git env--helper --type=bool --default=yes MISSING >actual &&
+	test-tool env-helper --type=bool --default=yes MISSING >actual &&
 	test_cmp expected actual &&
-	git env--helper --type=bool --default=true MISSING >actual &&
+	test-tool env-helper --type=bool --default=true MISSING >actual &&
 	test_cmp expected actual &&
 	echo false >expected &&
-	test_must_fail git env--helper --type=bool --default=0 MISSING >actual &&
+	test_must_fail test-tool env-helper --type=bool --default=0 MISSING >actual &&
 	test_cmp expected actual &&
-	test_must_fail git env--helper --type=bool --default=no MISSING >actual &&
+	test_must_fail test-tool env-helper --type=bool --default=no MISSING >actual &&
 	test_cmp expected actual &&
-	test_must_fail git env--helper --type=bool --default=false MISSING >actual &&
+	test_must_fail test-tool env-helper --type=bool --default=false MISSING >actual &&
 	test_cmp expected actual &&
 
 	# No output with --exit-code
-	git env--helper --type=bool --default=true --exit-code MISSING >actual.out 2>actual.err &&
+	test-tool env-helper --type=bool --default=true --exit-code MISSING >actual.out 2>actual.err &&
 	test_must_be_empty actual.out &&
 	test_must_be_empty actual.err &&
-	test_must_fail git env--helper --type=bool --default=false --exit-code MISSING >actual.out 2>actual.err &&
+	test_must_fail test-tool env-helper --type=bool --default=false --exit-code MISSING >actual.out 2>actual.err &&
 	test_must_be_empty actual.out &&
 	test_must_be_empty actual.err &&
 
 	# Existing variable
-	EXISTS=true git env--helper --type=bool --default=false --exit-code EXISTS >actual.out 2>actual.err &&
+	EXISTS=true test-tool env-helper --type=bool --default=false --exit-code EXISTS >actual.out 2>actual.err &&
 	test_must_be_empty actual.out &&
 	test_must_be_empty actual.err &&
 	test_must_fail \
 		env EXISTS=false \
-		git env--helper --type=bool --default=true --exit-code EXISTS >actual.out 2>actual.err &&
+		test-tool env-helper --type=bool --default=true --exit-code EXISTS >actual.out 2>actual.err &&
 	test_must_be_empty actual.out &&
 	test_must_be_empty actual.err
 '
 
-test_expect_success 'env--helper --type=ulong' '
+test_expect_success 'test-tool env-helper --type=ulong' '
 	echo 1234567890 >expected &&
-	git env--helper --type=ulong --default=1234567890 MISSING >actual.out 2>actual.err &&
+	test-tool env-helper --type=ulong --default=1234567890 MISSING >actual.out 2>actual.err &&
 	test_cmp expected actual.out &&
 	test_must_be_empty actual.err &&
 
 	echo 0 >expected &&
-	test_must_fail git env--helper --type=ulong --default=0 MISSING >actual &&
+	test_must_fail test-tool env-helper --type=ulong --default=0 MISSING >actual &&
 	test_cmp expected actual &&
 
-	git env--helper --type=ulong --default=1234567890 --exit-code MISSING >actual.out 2>actual.err &&
+	test-tool env-helper --type=ulong --default=1234567890 --exit-code MISSING >actual.out 2>actual.err &&
 	test_must_be_empty actual.out &&
 	test_must_be_empty actual.err &&
 
-	EXISTS=1234567890 git env--helper --type=ulong --default=0 EXISTS --exit-code >actual.out 2>actual.err &&
+	EXISTS=1234567890 test-tool env-helper --type=ulong --default=0 EXISTS --exit-code >actual.out 2>actual.err &&
 	test_must_be_empty actual.out &&
 	test_must_be_empty actual.err &&
 
 	echo 1234567890 >expected &&
-	EXISTS=1234567890 git env--helper --type=ulong --default=0 EXISTS >actual.out 2>actual.err &&
+	EXISTS=1234567890 test-tool env-helper --type=ulong --default=0 EXISTS >actual.out 2>actual.err &&
 	test_cmp expected actual.out &&
 	test_must_be_empty actual.err
 '
 
-test_expect_success 'env--helper reads config thanks to trace2' '
+test_expect_success 'test-tool env-helper reads config thanks to trace2' '
 	mkdir home &&
 	git config -f home/.gitconfig include.path cycle &&
 	git config -f home/cycle include.path .gitconfig &&
@@ -93,7 +93,7 @@ test_expect_success 'env--helper reads config thanks to trace2' '
 
 	test_must_fail \
 		env HOME="$(pwd)/home" GIT_TEST_ENV_HELPER=true \
-		git -C cycle env--helper --type=bool --default=0 --exit-code GIT_TEST_ENV_HELPER 2>err &&
+		test-tool -C cycle env-helper --type=bool --default=0 --exit-code GIT_TEST_ENV_HELPER 2>err &&
 	grep "exceeded maximum include depth" err
 '
 
diff --git a/t/test-lib-functions.sh b/t/test-lib-functions.sh
index 54e74d5301d..525055d44bc 100644
--- a/t/test-lib-functions.sh
+++ b/t/test-lib-functions.sh
@@ -1422,7 +1422,7 @@ test_bool_env () {
 		BUG "test_bool_env requires two parameters (variable name and default value)"
 	fi
 
-	git env--helper --type=bool --default="$2" --exit-code "$1"
+	test-tool env-helper --type=bool --default="$2" --exit-code "$1"
 	ret=$?
 	case $ret in
 	0|1)	# unset or valid bool value
diff --git a/t/test-lib.sh b/t/test-lib.sh
index 4fab1c1984c..01e88781dd2 100644
--- a/t/test-lib.sh
+++ b/t/test-lib.sh
@@ -1542,8 +1542,8 @@ then
 	# Normalize with test_bool_env
 	passes_sanitize_leak=
 
-	# We need to see TEST_PASSES_SANITIZE_LEAK in "git
-	# env--helper" (via test_bool_env)
+	# We need to see TEST_PASSES_SANITIZE_LEAK in "test-tool
+	# env-helper" (via test_bool_env)
 	export TEST_PASSES_SANITIZE_LEAK
 	if test_bool_env TEST_PASSES_SANITIZE_LEAK false
 	then
@@ -1682,7 +1682,7 @@ yes () {
 # The GIT_TEST_FAIL_PREREQS code hooks into test_set_prereq(), and
 # thus needs to be set up really early, and set an internal variable
 # for convenience so the hot test_set_prereq() codepath doesn't need
-# to call "git env--helper" (via test_bool_env). Only do that work
+# to call "test-tool env-helper" (via test_bool_env). Only do that work
 # if needed by seeing if GIT_TEST_FAIL_PREREQS is set at all.
 GIT_TEST_FAIL_PREREQS_INTERNAL=
 if test -n "$GIT_TEST_FAIL_PREREQS"
