diff --git a/Gemfile b/Gemfile
index bb2ec6c7b..63ba43c9a 100644
--- a/Gemfile
+++ b/Gemfile
@@ -210,7 +210,7 @@ gem "rubyzip", "2.3.2", require: "zip"
 # https://github.com/gitlabhq/gitlabhq/issues/3826
 # https://github.com/gitlabhq/gitlabhq/pull/3852
 # https://github.com/discourse/discourse/pull/238
-gem "minitest"
+gem "minitest",  "5.15.0"
 
 gem "versionist", "2.0.1"
 
diff --git a/Gemfile.lock b/Gemfile.lock
index 4e2ed9262..9bc5ce168 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -844,7 +844,7 @@ DEPENDENCIES
   markdown-it-html5-embed (= 1.0.0)
   markerb (= 1.1.0)
   mini_magick (= 4.11.0)
-  minitest
+  minitest (= 5.15.0)
   mobile-fu (= 1.4.0)
   mysql2 (= 0.5.4)
   nokogiri (= 1.12.5)