migration_test_helper

= MigrationTestHelper

MigrationTestHelper provides methods which let you assert the current state of the schema and run your migrations against the test database.

== Install

./script/plugin install svn://rubyforge.org/var/svn/migrationtest/tags/migration_test_helper

OR

gem install migration_test_helper

If you're using it outside of a Rails environment (for whatever reason) include the MigrationTestHelper module in your tests:

require 'test/unit' require 'migration_test_helper'

class MyTest < Test::Unit::TestCase include MigrationTestHelper

def test_something
  ...
end

end

== Use

assert_schema: verifies the schema of the database exactly matches the one specified.

def test_the_schema assert_schema do |s| s.table :books do |t| t.column :id, :integer t.column :title, :string, :limit => 5 t.column :author, :string end

  s.table :reviews do |t|
    t.column :id,      :integer
    t.column :book_id, :integer
    t.column :body,    :text
    t.column :rating,  :integer, :default => 0
    t.index  :book_id, :name => 'index_book_id_on_reviews'
  end
end

end

This would verify there are only two tables defined in the test database: books and reviews (schema_info is ignored). It will also verify that the book table has the three columns, id, title and author, each with their respective types. Indexes are verified too.

assert_table: verify a table is found exactly as specified:

assert_table :books do |t| t.column :id, :integer t.column :title, :string, :limit => 5 t.column :author, :string t.index :author, :name => 'index_author_on_books' end

drop_all_tables: does just what it says to your test database.

migrate: executes the migrations against the test database using the same mechanism as rake db:migrate.

def test_the_migrations migrate migrate :version => 0 migrate :version => 10 migrate end

This would do the same thing as running the following rake commands, but within a test case:

rake db:migrate rake db:migrate VERSION=0 rake db:migrate VERSION=10 rake db:migrate

By combining the two helpers you can write a test that shows you can run all your migrations and get the final schema:

def test_should_be_able_to_migrate_from_an_empty_schema drop_all_tables

# we shouldn't have any tables
assert_schema do |s|
end

migrate  

assert_schema do |s|
  s.table :books do |t|
    t.column :id,     :integer
    t.column :title,  :string
    t.column :author, :string
  end

  s.table :reviews do |t|
    t.column :id,      :integer
    t.column :book_id, :integer
    t.column :body,    :text
    t.column :rating,  :integer
    t.index  :book_id, :name => 'index_book_id_on_reviews'
  end
end

end

The migrate helper can also be useful for testing data tranformation migrations:

def test_should_get_rid_of_bad_data drop_all_tables migrate :version => 7 Book.reset_column_information book = Book.create! :title => "bad title\nwith\todd spacing" migrate :version => 8 # should cleanse spacing in book titles book.reload assert_equal "bad title with odd spacing", book.title end