diff --git a/lib/test/unit/assertions.rb b/lib/test/unit/assertions.rb
index 98d01df754..869baf505f 100644
--- a/lib/test/unit/assertions.rb
+++ b/lib/test/unit/assertions.rb
@@ -422,6 +422,26 @@ EOT
       alias assert_include assert_includes
       alias assert_not_include assert_not_includes
 
+      def assert_all?(obj, m = nil, &blk)
+        failed = []
+        obj.each do |*a, &b|
+          unless blk.call(*a, &b)
+            failed << (a.size > 1 ? a : a[0])
+          end
+        end
+        assert(failed.empty?, message(m) {failed.pretty_inspect})
+      end
+
+      def assert_not_all?(obj, m = nil, &blk)
+        failed = []
+        obj.each do |*a, &b|
+          if blk.call(*a, &b)
+            failed << a.size > 1 ? a : a[0]
+          end
+        end
+        assert(failed.empty?, message(m) {failed.pretty_inspect})
+      end
+
       def build_message(head, template=nil, *arguments) #:nodoc:
         template &&= template.chomp
         template.gsub(/\G((?:[^\\]|\\.)*?)(\\)?\?/) { $1 + ($2 ? "?" : mu_pp(arguments.shift)) }