+ # I don't know if there really is a good way to test this:
+ big_string = 'A' * (1024 * 512)
+ @reg['foo'] = big_string+'a'
+
+ dbfile = @reg.filename
+ assert_not_nil(dbfile)
+ if not File.exists? dbfile
+ # dbm ext. are arbitary
+ dbfile = Dir.glob(dbfile+'.*').first
+ end
+ assert_not_nil(dbfile)
+
+ assert(File.exists?(dbfile), 'expected database to exist')
+
+ size_before = File.size(dbfile)
+ @reg['bar'] = big_string
+ @reg.flush
+ size_after = File.size(dbfile)
+
+ assert(size_before < size_after, 'expected big string to be flushed on disk!')