2 files changed, 38 insertions, 0 deletions
diff --git a/test/dbm/test_dbm.rb b/test/dbm/test_dbm.rb
new file mode 100644
index 0000000000..f9198903a3
--- /dev/null
+++ b/test/dbm/test_dbm.rb
@@ -0,0 +1,31 @@
+require 'test/unit/testsuite'
+require 'test/unit/testcase'
+
+begin
+  require 'dbm'
+rescue LoadError
+end
+
+if defined? DBM
+  require 'tmpdir'
+  require 'fileutils'
+
+  class TestDBM < Test::Unit::TestCase
+    TMPROOT = "#{Dir.tmpdir}/ruby-gdbm.#{$$}"
+
+    def setup
+      Dir.mkdir TMPROOT
+    end
+
+    def teardown
+      FileUtils.rm_rf TMPROOT if File.directory?(TMPROOT)
+    end
+
+    def test_freeze
+      DBM.open("#{TMPROOT}/a.dbm") {|d|
+        d.freeze
+        assert_raises(TypeError) { d["k"] = "v" }
+      }
+    end
+  end
+end
diff --git a/test/gdbm/test_gdbm.rb b/test/gdbm/test_gdbm.rb
index a4bddfe078..ca0110cd91 100644
--- a/test/gdbm/test_gdbm.rb
+++ b/test/gdbm/test_gdbm.rb
@@ -29,5 +29,12 @@ if defined? GDBM
       }
       assert(v)
     end
+
+    def test_freeze
+      GDBM.open("#{TMPROOT}/a.dbm") {|d|
+        d.freeze
+        assert_raises(TypeError) { d["k"] = "v" }
+      }
+    end
   end
 end