This class provides a TestCase for testing generators. To setup, you need just to configure the destination and set which generator is being tested:

class AppGeneratorTest < Rails::Generators::TestCase
  tests AppGenerator
  destination File.expand_path("../tmp", File.dirname(__FILE__))
end

If you want to ensure your destination root is clean before running each test, you can set a setup callback:

class AppGeneratorTest < Rails::Generators::TestCase
  tests AppGenerator
  destination File.expand_path("../tmp", File.dirname(__FILE__))
  setup :prepare_destination
end
Methods
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Included Modules
Class Public methods
arguments(array)

Sets default arguments on generator invocation. This can be overwritten when invoking it.

arguments %w(app_name --skip-active-record)
# File railties/lib/rails/generators/test_case.rb, line 57
def self.arguments(array)
  self.default_arguments = array
end
destination(path)

Sets the destination of generator files:

destination File.expand_path("../tmp", File.dirname(__FILE__))
# File railties/lib/rails/generators/test_case.rb, line 65
def self.destination(path)
  self.destination_root = path
end
tests(klass)

Sets which generator should be tested:

tests AppGenerator
# File railties/lib/rails/generators/test_case.rb, line 48
def self.tests(klass)
  self.generator_class = klass
end
Instance Public methods
assert_class_method(method, content, &block)

Asserts the given class method exists in the given content. This method does not detect class methods inside (class << self), only class methods which starts with “self.”. When a block is given, it yields the content of the method.

assert_migration "db/migrate/create_products.rb" do |migration|
  assert_class_method :up, migration do |up|
    assert_match(/create_table/, up)
  end
end
# File railties/lib/rails/generators/test_case.rb, line 155
def assert_class_method(method, content, &block)
  assert_instance_method "self.#{method}", content, &block
end
assert_directory(relative, *contents)
assert_field_default_value(attribute_type, value)

Asserts the given attribute type gets a proper default value:

assert_field_default_value :string, "MyString"
# File railties/lib/rails/generators/test_case.rb, line 187
def assert_field_default_value(attribute_type, value)
  assert_equal(value, create_generated_attribute(attribute_type).default)
end
assert_field_type(attribute_type, field_type)

Asserts the given attribute type gets translated to a field type properly:

assert_field_type :date, :date_select
# File railties/lib/rails/generators/test_case.rb, line 179
def assert_field_type(attribute_type, field_type)
  assert_equal(field_type, create_generated_attribute(attribute_type).field_type)
end
assert_file(relative, *contents)

Asserts a given file exists. You need to supply an absolute path or a path relative to the configured destination:

assert_file "config/environment.rb"

You can also give extra arguments. If the argument is a regexp, it will check if the regular expression matches the given file content. If it's a string, it compares the file with the given string:

assert_file "config/environment.rb", /initialize/

Finally, when a block is given, it yields the file content:

assert_file "app/controller/products_controller.rb" do |controller|
  assert_instance_method :index, content do |index|
    assert_match(/Product\.all/, index)
  end
end
Also aliased as: assert_directory
# File railties/lib/rails/generators/test_case.rb, line 88
def assert_file(relative, *contents)
  absolute = File.expand_path(relative, destination_root)
  assert File.exists?(absolute), "Expected file #{relative.inspect} to exist, but does not"

  read = File.read(absolute) if block_given? || !contents.empty?
  yield read if block_given?

  contents.each do |content|
    case content
      when String
        assert_equal content, read
      when Regexp
        assert_match content, read
    end
  end
end
assert_instance_method(method, content)

Asserts the given method exists in the given content. When a block is given, it yields the content of the method.

assert_file "app/controller/products_controller.rb" do |controller|
  assert_instance_method :index, content do |index|
    assert_match(/Product\.all/, index)
  end
end
Also aliased as: assert_method
# File railties/lib/rails/generators/test_case.rb, line 168
def assert_instance_method(method, content)
  assert content =~ /def #{method}(\(.+\))?(.*?)\n  end/, "Expected to have method #{method}"
  yield $2.strip if block_given?
end
assert_method(method, content)
assert_migration(relative, *contents, &block)

Asserts a given migration exists. You need to supply an absolute path or a path relative to the configured destination:

assert_migration "db/migrate/create_products.rb"

This method manipulates the given path and tries to find any migration which matches the migration name. For example, the call above is converted to:

assert_file "db/migrate/003_create_products.rb"

Consequently, #assert_migration accepts the same arguments has assert_file.

# File railties/lib/rails/generators/test_case.rb, line 129
def assert_migration(relative, *contents, &block)
  file_name = migration_file_name(relative)
  assert file_name, "Expected migration #{relative} to exist, but was not found"
  assert_file file_name, *contents, &block
end
assert_no_directory(relative)
assert_no_file(relative)

Asserts a given file does not exist. You need to supply an absolute path or a path relative to the configured destination:

assert_no_file "config/random.rb"
Also aliased as: assert_no_directory
# File railties/lib/rails/generators/test_case.rb, line 111
def assert_no_file(relative)
  absolute = File.expand_path(relative, destination_root)
  assert !File.exists?(absolute), "Expected file #{relative.inspect} to not exist, but does"
end
assert_no_migration(relative)

Asserts a given migration does not exist. You need to supply an absolute path or a path relative to the configured destination:

assert_no_migration "db/migrate/create_products.rb"
# File railties/lib/rails/generators/test_case.rb, line 140
def assert_no_migration(relative)
  file_name = migration_file_name(relative)
  assert_nil file_name, "Expected migration #{relative} to not exist, but found #{file_name}"
end
create_generated_attribute(attribute_type, name = 'test', index = nil)

Create a Rails::Generators::GeneratedAttribute by supplying the attribute type and, optionally, the attribute name:

create_generated_attribute(:string, 'name')
# File railties/lib/rails/generators/test_case.rb, line 221
def create_generated_attribute(attribute_type, name = 'test', index = nil)
  Rails::Generators::GeneratedAttribute.parse([name, attribute_type, index].compact.join(':'))
end
generator(args=self.default_arguments, options={}, config={})

Instantiate the generator.

# File railties/lib/rails/generators/test_case.rb, line 212
def generator(args=self.default_arguments, options={}, config={})
  @generator ||= self.generator_class.new(args, options, config.reverse_merge(:destination_root => destination_root))
end
run_generator(args=self.default_arguments, config={})

Runs the generator configured for this class. The first argument is an array like command line arguments:

class AppGeneratorTest < Rails::Generators::TestCase
  tests AppGenerator
  destination File.expand_path("../tmp", File.dirname(__FILE__))
  teardown :cleanup_destination_root

  test "database.yml is not created when skipping Active Record" do
    run_generator %w(myapp --skip-active-record)
    assert_no_file "config/database.yml"
  end
end

You can provide a configuration hash as second argument. This method returns the output printed by the generator.

# File railties/lib/rails/generators/test_case.rb, line 207
def run_generator(args=self.default_arguments, config={})
  capture(:stdout) { self.generator_class.start(args, config.reverse_merge(:destination_root => destination_root)) }
end
Instance Protected methods
prepare_destination()
# File railties/lib/rails/generators/test_case.rb, line 235
def prepare_destination
  rm_rf(destination_root)
  mkdir_p(destination_root)
end