add a gdbm test for [ruby-dev:23381]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@6161 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

test/gdbm/test_gdbm.rb

@@ -0,0 +1,33 @@
+require 'test/unit/testsuite'
+require 'test/unit/testcase'
+
+begin
+  require 'gdbm'
+rescue LoadError
+end
+
+if defined? GDBM
+  require 'tmpdir'
+  require 'fileutils'
+
+  class TestGDBM < 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_open
+      GDBM.open("#{TMPROOT}/a.dbm") {}
+      v = GDBM.open("#{TMPROOT}/a.dbm", nil, GDBM::READER) {|d|
+        assert_raises(GDBMError) { d["k"] = "v" }
+        true
+      }
+      assert(v)
+    end
+  end
+end