diff --git a/Makefile b/Makefile
index 991bafa6fb..8993cec274 100644
--- a/Makefile
+++ b/Makefile
@@ -659,11 +659,11 @@ TEST_BUILTINS_OBJS += test-date.o
 TEST_BUILTINS_OBJS += test-delta.o
 TEST_BUILTINS_OBJS += test-drop-caches.o
 TEST_BUILTINS_OBJS += test-dump-cache-tree.o
+TEST_BUILTINS_OBJS += test-dump-split-index.o
 TEST_BUILTINS_OBJS += test-lazy-init-name-hash.o
 TEST_BUILTINS_OBJS += test-sha1.o
 
 TEST_PROGRAMS_NEED_X += test-dump-fsmonitor
-TEST_PROGRAMS_NEED_X += test-dump-split-index
 TEST_PROGRAMS_NEED_X += test-dump-untracked-cache
 TEST_PROGRAMS_NEED_X += test-example-decorate
 TEST_PROGRAMS_NEED_X += test-fake-ssh
diff --git a/t/helper/test-dump-split-index.c b/t/helper/test-dump-split-index.c
index e44430b699..4e2fdb5e30 100644
--- a/t/helper/test-dump-split-index.c
+++ b/t/helper/test-dump-split-index.c
@@ -1,3 +1,4 @@
+#include "test-tool.h"
 #include "cache.h"
 #include "split-index.h"
 #include "ewah/ewok.h"
@@ -7,7 +8,7 @@ static void show_bit(size_t pos, void *data)
 	printf(" %d", (int)pos);
 }
 
-int cmd_main(int ac, const char **av)
+int cmd__dump_split_index(int ac, const char **av)
 {
 	struct split_index *si;
 	int i;
diff --git a/t/helper/test-tool.c b/t/helper/test-tool.c
index 85e09908b7..872a948cc3 100644
--- a/t/helper/test-tool.c
+++ b/t/helper/test-tool.c
@@ -14,6 +14,7 @@ static struct test_cmd cmds[] = {
 	{ "delta", cmd__delta },
 	{ "drop-caches", cmd__drop_caches },
 	{ "dump-cache-tree", cmd__dump_cache_tree },
+	{ "dump-split-index", cmd__dump_split_index },
 	{ "lazy-init-name-hash", cmd__lazy_init_name_hash },
 	{ "sha1", cmd__sha1 },
 };
diff --git a/t/helper/test-tool.h b/t/helper/test-tool.h
index 2a0d034adf..e8363e851f 100644
--- a/t/helper/test-tool.h
+++ b/t/helper/test-tool.h
@@ -8,6 +8,7 @@ int cmd__date(int argc, const char **argv);
 int cmd__delta(int argc, const char **argv);
 int cmd__drop_caches(int argc, const char **argv);
 int cmd__dump_cache_tree(int argc, const char **argv);
+int cmd__dump_split_index(int argc, const char **argv);
 int cmd__lazy_init_name_hash(int argc, const char **argv);
 int cmd__sha1(int argc, const char **argv);
 
diff --git a/t/t0090-cache-tree.sh b/t/t0090-cache-tree.sh
index f81e3deead..3266209e41 100755
--- a/t/t0090-cache-tree.sh
+++ b/t/t0090-cache-tree.sh
@@ -246,9 +246,9 @@ test_expect_success 'switching trees does not invalidate shared index' '
 	git update-index --split-index &&
 	>split &&
 	git add split &&
-	test-dump-split-index .git/index | grep -v ^own >before &&
+	test-tool dump-split-index .git/index | grep -v ^own >before &&
 	git commit -m "as-is" &&
-	test-dump-split-index .git/index | grep -v ^own >after &&
+	test-tool dump-split-index .git/index | grep -v ^own >after &&
 	test_cmp before after
 '
 
diff --git a/t/t1700-split-index.sh b/t/t1700-split-index.sh
index b778975de8..ec179fbaf7 100755
--- a/t/t1700-split-index.sh
+++ b/t/t1700-split-index.sh
@@ -11,7 +11,7 @@ sane_unset GIT_FSMONITOR_TEST
 test_expect_success 'enable split index' '
 	git config splitIndex.maxPercentChange 100 &&
 	git update-index --split-index &&
-	test-dump-split-index .git/index >actual &&
+	test-tool dump-split-index .git/index >actual &&
 	indexversion=$(test-index-version <.git/index) &&
 	if test "$indexversion" = "4"
 	then
@@ -39,7 +39,7 @@ test_expect_success 'add one file' '
 	EOF
 	test_cmp ls-files.expect ls-files.actual &&
 
-	test-dump-split-index .git/index | sed "/^own/d" >actual &&
+	test-tool dump-split-index .git/index | sed "/^own/d" >actual &&
 	cat >expect <<-EOF &&
 	base $base
 	100644 $EMPTY_BLOB 0	one
@@ -57,8 +57,8 @@ test_expect_success 'disable split index' '
 	EOF
 	test_cmp ls-files.expect ls-files.actual &&
 
-	BASE=$(test-dump-split-index .git/index | grep "^own" | sed "s/own/base/") &&
-	test-dump-split-index .git/index | sed "/^own/d" >actual &&
+	BASE=$(test-tool dump-split-index .git/index | grep "^own" | sed "s/own/base/") &&
+	test-tool dump-split-index .git/index | sed "/^own/d" >actual &&
 	cat >expect <<-EOF &&
 	not a split index
 	EOF
@@ -73,7 +73,7 @@ test_expect_success 'enable split index again, "one" now belongs to base index"'
 	EOF
 	test_cmp ls-files.expect ls-files.actual &&
 
-	test-dump-split-index .git/index | sed "/^own/d" >actual &&
+	test-tool dump-split-index .git/index | sed "/^own/d" >actual &&
 	cat >expect <<-EOF &&
 	$BASE
 	replacements:
@@ -91,7 +91,7 @@ test_expect_success 'modify original file, base index untouched' '
 	EOF
 	test_cmp ls-files.expect ls-files.actual &&
 
-	test-dump-split-index .git/index | sed "/^own/d" >actual &&
+	test-tool dump-split-index .git/index | sed "/^own/d" >actual &&
 	q_to_tab >expect <<-EOF &&
 	$BASE
 	100644 2e0996000b7e9019eabcad29391bf0f5c7702f0b 0Q
@@ -111,7 +111,7 @@ test_expect_success 'add another file, which stays index' '
 	EOF
 	test_cmp ls-files.expect ls-files.actual &&
 
-	test-dump-split-index .git/index | sed "/^own/d" >actual &&
+	test-tool dump-split-index .git/index | sed "/^own/d" >actual &&
 	q_to_tab >expect <<-EOF &&
 	$BASE
 	100644 2e0996000b7e9019eabcad29391bf0f5c7702f0b 0Q
@@ -130,7 +130,7 @@ test_expect_success 'remove file not in base index' '
 	EOF
 	test_cmp ls-files.expect ls-files.actual &&
 
-	test-dump-split-index .git/index | sed "/^own/d" >actual &&
+	test-tool dump-split-index .git/index | sed "/^own/d" >actual &&
 	q_to_tab >expect <<-EOF &&
 	$BASE
 	100644 2e0996000b7e9019eabcad29391bf0f5c7702f0b 0Q
@@ -147,7 +147,7 @@ test_expect_success 'remove file in base index' '
 	EOF
 	test_cmp ls-files.expect ls-files.actual &&
 
-	test-dump-split-index .git/index | sed "/^own/d" >actual &&
+	test-tool dump-split-index .git/index | sed "/^own/d" >actual &&
 	cat >expect <<-EOF &&
 	$BASE
 	replacements:
@@ -165,7 +165,7 @@ test_expect_success 'add original file back' '
 	EOF
 	test_cmp ls-files.expect ls-files.actual &&
 
-	test-dump-split-index .git/index | sed "/^own/d" >actual &&
+	test-tool dump-split-index .git/index | sed "/^own/d" >actual &&
 	cat >expect <<-EOF &&
 	$BASE
 	100644 $EMPTY_BLOB 0	one
@@ -195,7 +195,7 @@ test_expect_success 'unify index, two files remain' '
 	EOF
 	test_cmp ls-files.expect ls-files.actual &&
 
-	test-dump-split-index .git/index | sed "/^own/d" >actual &&
+	test-tool dump-split-index .git/index | sed "/^own/d" >actual &&
 	cat >expect <<-EOF &&
 	not a split index
 	EOF
@@ -229,8 +229,8 @@ test_expect_success 'set core.splitIndex config variable to true' '
 	100644 e69de29bb2d1d6434b8b29ae775ad8c2e48c5391 0	two
 	EOF
 	test_cmp ls-files.expect ls-files.actual &&
-	BASE=$(test-dump-split-index .git/index | grep "^base") &&
-	test-dump-split-index .git/index | sed "/^own/d" >actual &&
+	BASE=$(test-tool dump-split-index .git/index | grep "^base") &&
+	test-tool dump-split-index .git/index | sed "/^own/d" >actual &&
 	cat >expect <<-EOF &&
 	$BASE
 	replacements:
@@ -248,7 +248,7 @@ test_expect_success 'set core.splitIndex config variable to false' '
 	100644 e69de29bb2d1d6434b8b29ae775ad8c2e48c5391 0	two
 	EOF
 	test_cmp ls-files.expect ls-files.actual &&
-	test-dump-split-index .git/index | sed "/^own/d" >actual &&
+	test-tool dump-split-index .git/index | sed "/^own/d" >actual &&
 	cat >expect <<-EOF &&
 	not a split index
 	EOF
@@ -259,8 +259,8 @@ test_expect_success 'set core.splitIndex config variable to true' '
 	git config core.splitIndex true &&
 	: >three &&
 	git update-index --add three &&
-	BASE=$(test-dump-split-index .git/index | grep "^base") &&
-	test-dump-split-index .git/index | sed "/^own/d" >actual &&
+	BASE=$(test-tool dump-split-index .git/index | grep "^base") &&
+	test-tool dump-split-index .git/index | sed "/^own/d" >actual &&
 	cat >expect <<-EOF &&
 	$BASE
 	replacements:
@@ -269,7 +269,7 @@ test_expect_success 'set core.splitIndex config variable to true' '
 	test_cmp expect actual &&
 	: >four &&
 	git update-index --add four &&
-	test-dump-split-index .git/index | sed "/^own/d" >actual &&
+	test-tool dump-split-index .git/index | sed "/^own/d" >actual &&
 	cat >expect <<-EOF &&
 	$BASE
 	100644 e69de29bb2d1d6434b8b29ae775ad8c2e48c5391 0	four
@@ -283,8 +283,8 @@ test_expect_success 'check behavior with splitIndex.maxPercentChange unset' '
 	git config --unset splitIndex.maxPercentChange &&
 	: >five &&
 	git update-index --add five &&
-	BASE=$(test-dump-split-index .git/index | grep "^base") &&
-	test-dump-split-index .git/index | sed "/^own/d" >actual &&
+	BASE=$(test-tool dump-split-index .git/index | grep "^base") &&
+	test-tool dump-split-index .git/index | sed "/^own/d" >actual &&
 	cat >expect <<-EOF &&
 	$BASE
 	replacements:
@@ -293,7 +293,7 @@ test_expect_success 'check behavior with splitIndex.maxPercentChange unset' '
 	test_cmp expect actual &&
 	: >six &&
 	git update-index --add six &&
-	test-dump-split-index .git/index | sed "/^own/d" >actual &&
+	test-tool dump-split-index .git/index | sed "/^own/d" >actual &&
 	cat >expect <<-EOF &&
 	$BASE
 	100644 e69de29bb2d1d6434b8b29ae775ad8c2e48c5391 0	six
@@ -307,8 +307,8 @@ test_expect_success 'check splitIndex.maxPercentChange set to 0' '
 	git config splitIndex.maxPercentChange 0 &&
 	: >seven &&
 	git update-index --add seven &&
-	BASE=$(test-dump-split-index .git/index | grep "^base") &&
-	test-dump-split-index .git/index | sed "/^own/d" >actual &&
+	BASE=$(test-tool dump-split-index .git/index | grep "^base") &&
+	test-tool dump-split-index .git/index | sed "/^own/d" >actual &&
 	cat >expect <<-EOF &&
 	$BASE
 	replacements:
@@ -317,8 +317,8 @@ test_expect_success 'check splitIndex.maxPercentChange set to 0' '
 	test_cmp expect actual &&
 	: >eight &&
 	git update-index --add eight &&
-	BASE=$(test-dump-split-index .git/index | grep "^base") &&
-	test-dump-split-index .git/index | sed "/^own/d" >actual &&
+	BASE=$(test-tool dump-split-index .git/index | grep "^base") &&
+	test-tool dump-split-index .git/index | sed "/^own/d" >actual &&
 	cat >expect <<-EOF &&
 	$BASE
 	replacements: