rails3's default unit tests is not working

When I try to execute default unit tests which have been created with my models, I get following errors.

CASE 1) My default unit test file content;

require 'test_helper' class UserTest < ActiveSupport::TestCase    # Replace this with your real tests.    test "the truth" do        assert true    end end

Commands that I executed;

rake db:migrate rake db:test:load rake test:units --trace

(in /home/mustafakyr/Code/trunk/MyProject) ** Invoke test:units (first_time) ** Invoke test:prepare (first_time) ** Invoke db:test:prepare (first_time) ** Invoke db:abort_if_pending_migrations (first_time) ** Invoke environment (first_time) ** Execute environment ** Execute db:abort_if_pending_migrations ** Execute db:test:prepare ** Invoke db:test:load (first_time) ** Invoke db:test:purge (first_time) ** Invoke environment ** Execute db:test:purge ** Execute db:test:load ** Invoke db:schema:load (first_time) ** Invoke environment ** Execute db:schema:load ** Execute test:prepare ** Execute test:units test/unit/user_test.rb:5:in `test': unknown command 't' (ArgumentError)   from test/unit/user_test.rb:5:in `<class:UserTest>'   from test/unit/user_test.rb:3:in `<top (required)>'   from /usr/local/lib/ruby/1.9.1/rake/rake_test_loader.rb:5:in `load'   from /usr/local/lib/ruby/1.9.1/rake/rake_test_loader.rb:5:in `block in <main>'   from /usr/local/lib/ruby/1.9.1/rake/rake_test_loader.rb:5:in `each'   from /usr/local/lib/ruby/1.9.1/rake/rake_test_loader.rb:5:in `<main>' rake aborted! Command failed with status (1): [/usr/local/bin/ruby -I"lib:test" "/usr/loc...] /usr/local/lib/ruby/1.9.1/rake.rb:993:in `block in sh' /usr/local/lib/ruby/1.9.1/rake.rb:1008:in `call' /usr/local/lib/ruby/1.9.1/rake.rb:1008:in `sh' /usr/local/lib/ruby/1.9.1/rake.rb:1092:in `sh' /usr/local/lib/ruby/1.9.1/rake.rb:1027:in `ruby' /usr/local/lib/ruby/1.9.1/rake.rb:1092:in `ruby' /usr/local/lib/ruby/gems/1.9.1/gems/railties-3.0.3/lib/rails/test_unit/testing.rake:26:in `block (2 levels) in define' /usr/local/lib/ruby/1.9.1/rake.rb:1110:in `verbose' /usr/local/lib/ruby/gems/1.9.1/gems/railties-3.0.3/lib/rails/test_unit/testing.rake:11:in `block in define' /usr/local/lib/ruby/1.9.1/rake.rb:634:in `call' /usr/local/lib/ruby/1.9.1/rake.rb:634:in `block in execute' /usr/local/lib/ruby/1.9.1/rake.rb:629:in `each' /usr/local/lib/ruby/1.9.1/rake.rb:629:in `execute' /usr/local/lib/ruby/1.9.1/rake.rb:595:in `block in invoke_with_call_chain' /usr/local/lib/ruby/1.9.1/monitor.rb:201:in `mon_synchronize' /usr/local/lib/ruby/1.9.1/rake.rb:588:in `invoke_with_call_chain' /usr/local/lib/ruby/1.9.1/rake.rb:581:in `invoke' /usr/local/lib/ruby/1.9.1/rake.rb:2041:in `invoke_task' /usr/local/lib/ruby/1.9.1/rake.rb:2019:in `block (2 levels) in top_level' /usr/local/lib/ruby/1.9.1/rake.rb:2019:in `each' /usr/local/lib/ruby/1.9.1/rake.rb:2019:in `block in top_level' /usr/local/lib/ruby/1.9.1/rake.rb:2058:in `standard_exception_handling' /usr/local/lib/ruby/1.9.1/rake.rb:2013:in `top_level' /usr/local/lib/ruby/1.9.1/rake.rb:1992:in `run' /usr/local/bin/rake:31:in `<main>

CASE 2) Then when I use following unit test file it is working, but when I get an failure with test I get "rake aborted!" error.

My own unit test content;

require 'test_helper' class UserTest < ActiveSupport::TestCase    # Replace this with your real tests.    def test        assert false    end end

Commands that I executed;

rake test:units --trace

(in /home/mustafakyr/Code/trunk/MyProject) ** Invoke test:units (first_time) ** Invoke test:prepare (first_time) ** Invoke db:test:prepare (first_time) ** Invoke db:abort_if_pending_migrations (first_time) ** Invoke environment (first_time) ** Execute environment ** Execute db:abort_if_pending_migrations ** Execute db:test:prepare ** Invoke db:test:load (first_time) ** Invoke db:test:purge (first_time) ** Invoke environment ** Execute db:test:purge ** Execute db:test:load ** Invoke db:schema:load (first_time) ** Invoke environment ** Execute db:schema:load ** Execute test:prepare ** Execute test:units Loaded suite /usr/local/lib/ruby/1.9.1/rake/rake_test_loader Started F Finished in 0.115924 seconds.

  1) Failure: test(UserTest) [test/unit/user_test.rb:6]: Failed assertion, no message given.

1 tests, 1 assertions, 1 failures, 0 errors, 0 skips

Test run options: --seed 43445 rake aborted! Command failed with status (1): [/usr/local/bin/ruby -I"lib:test" "/usr/loc...] /usr/local/lib/ruby/1.9.1/rake.rb:993:in `block in sh' /usr/local/lib/ruby/1.9.1/rake.rb:1008:in `call' /usr/local/lib/ruby/1.9.1/rake.rb:1008:in `sh' /usr/local/lib/ruby/1.9.1/rake.rb:1092:in `sh' /usr/local/lib/ruby/1.9.1/rake.rb:1027:in `ruby' /usr/local/lib/ruby/1.9.1/rake.rb:1092:in `ruby' /usr/local/lib/ruby/gems/1.9.1/gems/railties-3.0.3/lib/rails/test_unit/testing.rake:26:in `block (2 levels) in define' /usr/local/lib/ruby/1.9.1/rake.rb:1110:in `verbose' /usr/local/lib/ruby/gems/1.9.1/gems/railties-3.0.3/lib/rails/test_unit/testing.rake:11:in `block in define' /usr/local/lib/ruby/1.9.1/rake.rb:634:in `call' /usr/local/lib/ruby/1.9.1/rake.rb:634:in `block in execute' /usr/local/lib/ruby/1.9.1/rake.rb:629:in `each' /usr/local/lib/ruby/1.9.1/rake.rb:629:in `execute' /usr/local/lib/ruby/1.9.1/rake.rb:595:in `block in invoke_with_call_chain' /usr/local/lib/ruby/1.9.1/monitor.rb:201:in `mon_synchronize' /usr/local/lib/ruby/1.9.1/rake.rb:588:in `invoke_with_call_chain' /usr/local/lib/ruby/1.9.1/rake.rb:581:in `invoke' /usr/local/lib/ruby/1.9.1/rake.rb:2041:in `invoke_task' /usr/local/lib/ruby/1.9.1/rake.rb:2019:in `block (2 levels) in top_level' /usr/local/lib/ruby/1.9.1/rake.rb:2019:in `each' /usr/local/lib/ruby/1.9.1/rake.rb:2019:in `block in top_level' /usr/local/lib/ruby/1.9.1/rake.rb:2058:in `standard_exception_handling' /usr/local/lib/ruby/1.9.1/rake.rb:2013:in `top_level' /usr/local/lib/ruby/1.9.1/rake.rb:1992:in `run' /usr/local/bin/rake:31:in `<main>'

gem env

RubyGems Environment:   - RUBYGEMS VERSION: 1.3.7   - RUBY VERSION: 1.9.2 (2010-12-25 patchlevel 136) [i686-linux]   - INSTALLATION DIRECTORY: /usr/local/lib/ruby/gems/1.9.1   - RUBY EXECUTABLE: /usr/local/bin/ruby   - EXECUTABLE DIRECTORY: /usr/local/bin   - RUBYGEMS PLATFORMS:     - ruby     - x86-linux   - GEM PATHS:      - /usr/local/lib/ruby/gems/1.9.1      - /home/mustafakyr/.gem/ruby/1.9.1   - GEM CONFIGURATION:      - :update_sources => true      - :verbose => true      - :benchmark => false      - :backtrace => false      - :bulk_threshold => 1000   - REMOTE SOURCES:      - http://rubygems.org/

gem list

*** LOCAL GEMS ***

abstract (1.0.0) actionmailer (3.0.3) actionpack (3.0.3) activemodel (3.0.3) activerecord (3.0.3) activeresource (3.0.3) activesupport (3.0.3) arel (2.0.6) authlogic (2.1.6) builder (2.1.2) bundler (1.0.7) cgi_multipart_eof_fix (2.5.0) daemon_controller (0.2.5) daemons (1.1.0) diff-lcs (1.1.2) erubis (2.6.6) eventmachine (0.12.10) extlib (0.9.15) fastthread (1.0.7) ffi (1.0.4) file-tail (1.0.5) gem_plugin (0.2.3) gga4r (0.9.2) gravatar (1.0) haml (3.0.25) highline (1.6.1) i18n (0.5.0) mail (2.2.13) mime-types (1.16) minitest (1.6.0) mysql (2.8.1) mysql2 (0.2.6) passenger (3.0.2) pg (0.10.0) polyglot (0.3.1) rack (1.2.1) rack-mount (0.6.13) rack-test (0.5.6) rails (3.0.3) railties (3.0.3) rake (0.8.7) rdoc (2.5.8) rubygems-update (1.4.1) scaffold (0.0.3) spruz (0.2.2) sqlite3 (0.1.1) sqlite3-ruby (1.3.2) templater (1.0.0) test-unit (2.1.2) thin (1.2.7) thor (0.14.6) treetop (1.4.9) tzinfo (0.3.23)

My default fixture file content;

# This model initially had no columns defined. If you add columns to the # model remove the '{}' from the fixture names and add the columns immediately # below each fixture, per the syntax in the comments below