101 lines
3.1 KiB
Plaintext
101 lines
3.1 KiB
Plaintext
h1. Database Cleaner
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Database Cleaner is a set of strategies for cleaning your database in Ruby.
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The original use case was to ensure a clean state during tests. Each strategy
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is a small amount of code but is code that is usually needed in any ruby app
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that is testing with a database.
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Right now the only ORM supported is ActiveRecord and it currently has two strategies:
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truncation and transaction.
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Support for DataMapper is built-in. All that needs to be written are the strategies. :)
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h2. How to use
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<pre>
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require 'database_cleaner'
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DatabaseCleaner.strategy = :truncation
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# then, whenever you need to clean the DB
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DatabaseCleaner.clean
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</pre>
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With the :truncation strategy you can also pass in options, for example:
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<pre>
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DatabaseCleaner.strategy = :truncation, {:only => %[widigets dogs some_other_table]}
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</pre>
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<pre>
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DatabaseCleaner.strategy = :truncation, {:except => %[widigets]}
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</pre>
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(I should point out the truncation strategy will never truncate your schema_migrations table.)
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Some strategies require that you call DatabaseCleaner.start before calling clean
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(for example the :transaction one needs to know to open up a transaction). So
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you would have:
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<pre>
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require 'database_cleaner'
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DatabaseCleaner.strategy = :transaction
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DatabaseCleaner.start # usually this is called in setup of a test
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dirty_the_db
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DatabaseCleaner.clean # cleanup of the test
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</pre>
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At times you may want to do a single clean with one strategy. For example, you may want
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to start the process by truncating all the tables, but then use the faster transaction
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strategy the remaining time. To accomplish this you can say:
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<pre>
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require 'database_cleaner'
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DatabaseCleaner.clean_with :truncation
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DatabaseCleaner.strategy = :transaction
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# then make the DatabaseCleaner.start and DatabaseCleaner.clean calls appropriately
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</pre>
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For use in Cucumber please see the section below.
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h2. Why?
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One of my motivations for writing this library was to have an easy way to
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turn on what Rails calls "transactional_fixtures" in my non-rails
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ActiveRecord projects. For example, Cucumber ships with a Rails world that
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will wrap each scenario in a transaction. This is great, but what if you are
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using ActiveRecord in a non-rails project? You used to have to copy-and-paste
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the needed code, but with DatabaseCleaner you can now say:
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<pre>
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#env.rb
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require 'database_cleaner'
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require 'database_cleaner/cucumber'
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DatabaseCleaner.strategy = :transaction
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</pre>
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Now lets say you are running your features and it requires that another process be
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involved (i.e. Selenium running against your app's server.) You can simply change
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your strategy type:
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<pre>
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#env.rb
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require 'database_cleaner'
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require 'database_cleaner/cucumber'
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DatabaseCleaner.strategy = :truncation
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</pre>
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You can have the best of both worlds and use the best one for the job:
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<pre>
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#env.rb
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require 'database_cleaner'
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require 'database_cleaner/cucumber'
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DatabaseCleaner.strategy = (ENV['SELENIUM'] == 'true') ? :truncation : :transaction
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</pre>
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h2. COPYRIGHT
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Copyright (c) 2009 Ben Mabey. See LICENSE for details.
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