diff --git a/test/test_securerandom.rb b/test/test_securerandom.rb
index 0a78624..c51bec2 100644
--- a/test/test_securerandom.rb
+++ b/test/test_securerandom.rb
@@ -164,6 +164,27 @@ end
     end
   end
 
+  def test_choose
+    65.times do |idx|
+      ch = @it.choose([*'a'..'e', *'0'..'5'])
+      assert_match(/^[a-e0-5]+$/, ch)
+    end
+  end
+
+  def test_graph
+    65.times do |idx|
+      g = @it.graph
+      assert_match(/^[!-~]+$/, g)
+    end
+  end
+
+  def test_alphanumeric
+    65.times do |idx|
+      an = @it.alphanumeric
+      assert_match(/^[0-9a-zA-Z]+$/, an)
+    end
+  end
+
   def protect
     begin
       yield