请高手指教

我在测试rails时，出现的错误：弄了，半天，不知道那地方错误，请高手指点
1) Error:
test_truth(MemberTest):
ActiveRecord::StatementInvalid: Mysql::Error: #23000Duplicate entry '' for key 2
: INSERT INTO members (`id`) VALUES (1)
    c:/ruby/lib/ruby/gems/1.8/gems/activerecord-1.15.5/lib/active_record/connect
ion_adapters/abstract_adapter.rb:128:in `log'
    c:/ruby/lib/ruby/gems/1.8/gems/activerecord-1.15.5/lib/active_record/connect
ion_adapters/mysql_adapter.rb:243:in `execute'
    c:/ruby/lib/ruby/gems/1.8/gems/activerecord-1.15.5/lib/active_record/fixture
s.rb:290:in `insert_fixtures'
    c:/ruby/lib/ruby/gems/1.8/gems/activerecord-1.15.5/lib/active_record/fixture
s.rb:289:in `each'
    c:/ruby/lib/ruby/gems/1.8/gems/activerecord-1.15.5/lib/active_record/fixture
s.rb:289:in `insert_fixtures'
    c:/ruby/lib/ruby/gems/1.8/gems/activerecord-1.15.5/lib/active_record/fixture
s.rb:257:in `create_fixtures'
    c:/ruby/lib/ruby/gems/1.8/gems/activerecord-1.15.5/lib/active_record/fixture
s.rb:257:in `each'
    c:/ruby/lib/ruby/gems/1.8/gems/activerecord-1.15.5/lib/active_record/fixture
s.rb:257:in `create_fixtures'
    c:/ruby/lib/ruby/gems/1.8/gems/activerecord-1.15.5/lib/active_record/connect
ion_adapters/abstract/database_statements.rb:59:in `transaction'
    c:/ruby/lib/ruby/gems/1.8/gems/activerecord-1.15.5/lib/active_record/fixture
s.rb:255:in `create_fixtures'
    c:/ruby/lib/ruby/gems/1.8/gems/activerecord-1.15.5/lib/active_record/base.rb
:867:in `silence'
    c:/ruby/lib/ruby/gems/1.8/gems/activerecord-1.15.5/lib/active_record/fixture
s.rb:248:in `create_fixtures'
    c:/ruby/lib/ruby/gems/1.8/gems/activerecord-1.15.5/lib/active_record/fixture
s.rb:593:in `load_fixtures'
    c:/ruby/lib/ruby/gems/1.8/gems/activerecord-1.15.5/lib/active_record/fixture
s.rb:538:in `setup'

1 tests, 0 assertions, 0 failures, 1 errors