1 files changed, 1 insertions, 1 deletions
diff --git a/common.mk b/common.mk
index 936846d629..62e139a1d4 100644
--- a/common.mk
+++ b/common.mk
@@ -1349,7 +1349,7 @@ test-bundled-gems-prepare: $(TEST_RUNNABLE)-test-bundled-gems-prepare
 no-test-bundled-gems-prepare: no-test-bundled-gems-precheck
 yes-test-bundled-gems-prepare: yes-test-bundled-gems-precheck
 	$(XRUBY) -C "$(srcdir)" bin/gem install --no-document \
-		--install-dir .bundle --conservative "bundler" "minitest:~> 5" 'test-unit' 'rake' 'hoe' 'yard' 'pry' 'packnga' 'rexml'
+		--install-dir .bundle --conservative "bundler" "minitest:~> 5" "test-unit" "rake" "hoe" "yard" "pry" "packnga" "rexml" "json-schema"
 
 PREPARE_BUNDLED_GEMS = test-bundled-gems-prepare
 test-bundled-gems: $(TEST_RUNNABLE)-test-bundled-gems