module ActiveSupport::Testing::NotificationAssertions

# File lib/active_support/testing/notification_assertions.rb, line 66
def assert_no_notifications(pattern = nil, &block)
  notifications = capture_notifications(pattern, &block)
  error_message = if pattern
    "Expected no notifications for #{pattern} but found #{notifications.size}"
  else
    "Expected no notifications but found #{notifications.size}"
  end
  assert_empty(notifications, error_message)
end

Assert no notifications were emitted for a given pattern.

You can assert no notifications were emitted by passing a pattern, which accepts either a string or regexp, and a block. While the block is executed, if no matching notifications are emitted, the assertion will pass.

assert_no_notifications("post.submitted") do
  post.destroy # => emits non-matching notification
end

# File lib/active_support/testing/notification_assertions.rb, line 28
def assert_notification(pattern, payload = nil, &block)
  notifications = capture_notifications(pattern, &block)
  assert_not_empty(notifications, "No #{pattern} notifications were found")

  return notifications.first if payload.nil?

  notification = notifications.find { |notification| notification.payload.slice(*payload.keys) == payload }
  assert_not_nil(notification, "No #{pattern} notification with payload #{payload} was found")

  notification
end

Assert a notification was emitted with a given pattern and optional payload.

You can assert that a notification was emitted by passing a pattern, which accepts either a string or regexp, an optional payload, and a block. While the block is executed, if a matching notification is emitted, the assertion will pass and the notification will be returned.

Note that the payload is matched as a subset, meaning that the notification must contain at least the specified keys and values, but may contain additional ones.

assert_notification("post.submitted", title: "Cool Post") do
  post.submit(title: "Cool Post", body: "Cool Body") # => emits matching notification
end

Using the returned notification, you can make more customized assertions.

notification = assert_notification("post.submitted", title: "Cool Post") do
  ActiveSupport::Notifications.instrument("post.submitted", title: "Cool Post", body: Body.new("Cool Body"))
end

assert_instance_of(Body, notification.payload[:body])

# File lib/active_support/testing/notification_assertions.rb, line 51
def assert_notifications_count(pattern, count, &block)
  actual_count = capture_notifications(pattern, &block).count
  assert_equal(count, actual_count, "Expected #{count} instead of #{actual_count} notifications for #{pattern}")
end

Assert the number of notifications emitted with a given pattern.

You can assert the number of notifications emitted by passing a pattern, which accepts either a string or regexp, a count, and a block. While the block is executed, the number of matching notifications emitted will be counted. After the block’s execution completes, the assertion will pass if the count matches.

assert_notifications_count("post.submitted", 1) do
  post.submit(title: "Cool Post") # => emits matching notification
end

# File lib/active_support/testing/notification_assertions.rb, line 85
def capture_notifications(pattern = nil, &block)
  notifications = []
  ActiveSupport::Notifications.subscribed(->(n) { notifications << n }, pattern, &block)
  notifications
end

Capture emitted notifications, optionally filtered by a pattern.

You can capture emitted notifications, optionally filtered by a pattern, which accepts either a string or regexp, and a block.

notifications = capture_notifications("post.submitted") do
  post.submit(title: "Cool Post") # => emits matching notification
end