diff --git a/Gemfile b/Gemfile
index 1e2221f..a033755 100644
--- a/Gemfile
+++ b/Gemfile
@@ -26,7 +26,7 @@ gem 'glogin', '0.14.2'
 gem 'haml', '5.2.0'
 gem 'iri', '0.8.0'
 gem 'loog', '0.5.1'
-gem 'minitest', '5.21.2', require: false
+gem 'minitest', '5.23.1', require: false
 gem 'minitest-reporters', '1.6.1', require: false
 gem 'pgtk', '0.9.2'
 gem 'rack', '2.2.8.1'
diff --git a/Gemfile.lock b/Gemfile.lock
index b0c877d..6f76ae6 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -106,7 +106,7 @@ GEM
       crass (~> 1.0.2)
       nokogiri (>= 1.12.0)
     loog (0.5.1)
-    minitest (5.21.2)
+    minitest (5.23.1)
     minitest-reporters (1.6.1)
       ansi
       builder
@@ -300,7 +300,7 @@ DEPENDENCIES
   haml (= 5.2.0)
   iri (= 0.8.0)
   loog (= 0.5.1)
-  minitest (= 5.21.2)
+  minitest (= 5.23.1)
   minitest-reporters (= 1.6.1)
   pgtk (= 0.9.2)
   rack (= 2.2.8.1)