The README says it all:
You’re knee deep in a debugger session, and you can’t understand why something’s wrong. You wish you could fire up your application against the test database, but sadly, the process which is running the tests is within a transaction, and thus the actual data is opaque. What can you do?
1 # Somewhere deep in your tests 2 test "the frobble touches the widget" do 3 assert_equal 42, frobble.widget_id 4 end
You’ve been on this assert_equal call for the past hour wondering. Frustration’s been mounting, because you don’t understand why the frobble doesn’t touch the widget. Clearly, there’s something wrong with the fixtures, but you can’t understand what it is. Time to fire up the debugger and dump the data:
1 [814, 823] in test/unit/widget_test.rb 2 814 frobble.save! 3 815 end 4 816 5 817 test "the frobble touches the widget" do 6 818 debugger 7 => 819 assert_equal 42, frobble.widget_id 8 820 end 9 821 10 822 test "the widget touched the frobble in turn" do 11 823 assert widget.touched_by_frobble? 12 test/unit/widget_test.rb:819 13 => 819 assert_equal 42, frobble.widget_id 14 (rdb:112)
Since the data_dumper gem is already declared in your Gemfile (if not, declare it, bundle install, then run your tests again), type:
1 (rdb:112) File.mkdir(Rails.root + "dump") 2 (rdb:113) DataDumper.dump(Rails.root + "dump")
Then, quit your failing tests, and from the trusty command line:
1 $ rails console 2 > DataDumper.load(Rails.root + "dump") 3 > exit 4 5 $ rails server
Any and all data from your test database will be loaded in your development environment. You can now explore your model with your trusty application, to find out what’s really going on.
