diff --git a/ci/lib.sh b/ci/lib.sh
index c8c2c38..5fca043 100755
--- a/ci/lib.sh
+++ b/ci/lib.sh
@@ -156,7 +156,7 @@
 
 export DEVELOPER=1
 export DEFAULT_TEST_TARGET=prove
-export GIT_TEST_CLONE_2GB=YesPlease
+export GIT_TEST_CLONE_2GB=true
 
 case "$jobname" in
 linux-clang|linux-gcc)
diff --git a/t/t5608-clone-2gb.sh b/t/t5608-clone-2gb.sh
index 2c6bc07..eee0842 100755
--- a/t/t5608-clone-2gb.sh
+++ b/t/t5608-clone-2gb.sh
@@ -3,7 +3,7 @@
 test_description='Test cloning a repository larger than 2 gigabyte'
 . ./test-lib.sh
 
-if test -z "$GIT_TEST_CLONE_2GB"
+if ! test_bool_env GIT_TEST_CLONE_2GB false
 then
 	say 'Skipping expensive 2GB clone test; enable it with GIT_TEST_CLONE_2GB=t'
 else