Birdbath

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

Install

gem install birdbath

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

require 'test/unit'
require 'birdbath'

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

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

Authors