Rails 3: :null => false, tests and ActiveRecord::StatementInvalid: SQLite3::SQLException XXXXX may not be NULL

Okay, long description here, but follow me...

Create a new Rails project

rails testapp
cd testapp

Create your first resource

rails generate resource User

Create a migration that sets :null => false on a field

class CreateUsers < ActiveRecord::Migration
  def self.up
    create_table :users do |t|
      t.string :email, :null => false
      t.timestamps
    end
  end

  def self.down
    drop_table :users
  end
end

Run your migration

rake db:migrate

Try to run your default "test truth" tests

rake test:units

This gives the following error message:

Loaded suite /Users/marc/.bundle/ruby/1.8/gems/rake-0.8.7/lib/rake/rake_test_loader
Started
E
Finished in 0.066302 seconds.

  1) Error:
test_the_truth(UserTest):
ActiveRecord::StatementInvalid: SQLite3::SQLException: users.email may not be NULL: INSERT INTO "users" ("created_at", "updated_at", "id") VALUES ('2010-02-20 10:39:59', '2010-02-20 10:39:59', 298486374)
    

1 tests, 0 assertions, 0 failures, 1 errors
rake aborted!
Command failed with status (1): [/usr/local/bin/ruby -I"lib:test" "/Users/m...]

The same error pops up for any actual tests you create. The hangup seems to be any columns set to :null => false