Testing

View Source

Aurora Meter ships a test helper, AuroraMeter.Test, so your suite does not have to know how the runtime works.

defmodule MyApp.MeterCase do
  use ExUnit.CaseTemplate

  using do
    quote do
      use MyApp.DataCase              # your usual Ecto sandbox
      use AuroraMeter.Test            # imports the helpers below
    end
  end
end

Set large intervals in test config so the timers never fire mid-test, and drive them explicitly:

# config/test.exs
config :aurora_meter, flush_interval: 60_000, broadcast_interval: 60_000
AuroraMeter.Test.flush!()          # persists dirty counters, returns the count
AuroraMeter.Test.broadcast!()      # broadcasts touched counters (and gossips deltas)

Isolation

Counters live in a shared ETS table. Either give each test a unique tenant key (the default recommendation, works with async: true):

tenant = AuroraMeter.Test.unique_tenant()

or clear the tables before each test (requires async: false):

use AuroraMeter.Test, reset: true   # setup :reset_aurora_meter
# or
AuroraMeter.Test.reset!()

reset!/0 discards unflushed usage and never touches the database.

Sandbox

The flusher and broadcaster are background processes, so tests that flush must use shared sandbox mode (the standard DataCase pattern: Sandbox.start_owner!(Repo, shared: not tags[:async])). If your case template does not already do that, use AuroraMeter.Test, sandbox: true starts an owner on the configured repo.

Asserting live updates

AuroraMeter.LiveView.subscribe(tenant)
AuroraMeter.track(tenant, :ai_generations, 3)
AuroraMeter.Test.broadcast!()
assert_receive {:aurora_meter, :usage, %{feature: :ai_generations, value: 3}}

Simulating other nodes

Cluster behaviour can be exercised on one node:

AuroraMeter.track(tenant, :ai_generations, 2)

# another node gossips 5 increments
AuroraMeter.Test.simulate_node(:"web@10.0.0.2", [{tenant, :ai_generations, 5}])
assert AuroraMeter.usage(tenant, :ai_generations) == 7

# another node flushes and announces the database total
AuroraMeter.Test.simulate_flush(:"web@10.0.0.2", [{tenant, :ai_generations, 40}])
assert AuroraMeter.usage(tenant, :ai_generations) == 42   # 40 + our unflushed 2

See the clustering guide for what these messages mean.