module Rails::Generators::Testing::Assertions

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/testing/assertions.rb, line 88
def assert_class_method(method, content, &block)
  assert_instance_method "self.#{method}", content, &block
end

Asserts the given attribute type gets a proper default value:

assert_field_default_value :string, "MyString"

# File railties/lib/rails/generators/testing/assertions.rb, line 117
def assert_field_default_value(attribute_type, value)
  if value.nil?
    assert_nil(create_generated_attribute(attribute_type).default)
  else
    assert_equal(value, create_generated_attribute(attribute_type).default)
  end
end

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

assert_field_type :date, :date_select

# File railties/lib/rails/generators/testing/assertions.rb, line 110
def assert_field_type(attribute_type, field_type)
  assert_equal(field_type, create_generated_attribute(attribute_type).field_type)
end

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/controllers/products_controller.rb" do |controller|
  assert_instance_method :index, controller do |index|
    assert_match(/Product\.all/, index)
  end
end

# File railties/lib/rails/generators/testing/assertions.rb, line 25
def assert_file(relative, *contents)
  absolute = File.expand_path(relative, destination_root)
  assert File.exist?(absolute), "Expected file #{relative.inspect} to exist, but does not"

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

Asserts a given initializer exists. You need to supply a path relative to the ‘config/initializers/` directory.

assert_initializer "mail_interceptors.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_initializer "mail_interceptors.rb", /SandboxEmailInterceptor/

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

assert_initializer "mail_interceptors.rb" do |initializer|
  assert_match(/SandboxEmailInterceptor/, initializer)
end

# File railties/lib/rails/generators/testing/assertions.rb, line 141
def assert_initializer(name, *contents, &block)
  assert_file("config/initializers/#{name}", *contents, &block)
end

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

assert_file "app/controllers/products_controller.rb" do |controller|
  assert_instance_method :index, controller do |index|
    assert_match(/Product\.all/, index)
  end
end

# File railties/lib/rails/generators/testing/assertions.rb, line 100
def assert_instance_method(method, content)
  assert content =~ /(\s+)def #{method}(\(.+\))?(.*?)\n\1end/m, "Expected to have method #{method}"
  assert_nothing_raised { yield $3.strip } if block_given?
end

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/testing/assertions.rb, line 64
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

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"

# File railties/lib/rails/generators/testing/assertions.rb, line 47
def assert_no_file(relative)
  absolute = File.expand_path(relative, destination_root)
  assert !File.exist?(absolute), "Expected file #{relative.inspect} to not exist, but does"
end

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/testing/assertions.rb, line 74
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