tests: run MQTT test using container

**Asana Ticket**: [🍎 make MQTT tests work on MBTA network](https://app.asana.com/0/1204137169527258/1206661431136934/f)

Runs the Mosquitto broker as a container with `docker compose`. Publishes a test message in the MQTT test.

.github/workflows/elixir.yml

@@ -127,9 +127,18 @@ jobs:
         image: amazon/dynamodb-local:2.0.0
         ports:
           - 8000:8000
+      mosquitto:
+        image: eclipse-mosquitto:2.0
+        ports:
+          - 1883:1883
+        volumes:
+          - ./mosquitto:/mosquitto/config/
+        options: --name mqtt
 
     steps:
       - uses: actions/checkout@v3
+      - name: Restart MQTT to load mosquitto/mosquitto.conf from checkout
+        run: docker restart mqtt
       - name: ASDF cache
         uses: actions/cache@v3
         with:

README.md

@@ -16,6 +16,21 @@ To start your Phoenix app:
 
 Now you can visit [`localhost:4000`](http://localhost:4000) from your browser.
 
+## Tests
+
+To run the tests, first install and setup Colima, Docker, and docker-compose:
+
+```shell
+brew install docker docker-compose colima
+colima start
+mkdir -p ${DOCKER_CONFIG:-"~/.docker"}/cli-plugins
+ln -sfn /opt/homebrew/opt/docker-compose/bin/docker-compose ${DOCKER_CONFIG:-"~/.docker"}/cli-plugins/docker-compose
+```
+
+Then, start the Compose configuration in a separate window or tab and run the tests: 
+  1. `docker compose up` 
+  2. `mix test`
+
 ## Environment Variables
 
 In addition to the Elixir config files, the V3 API allows runtime configuration through a collection of environment variables.

apps/api_accounts/README.md

@@ -21,7 +21,7 @@ end
 
 ## Setting Up DynamoDB Local
 
-Make sure you have Docker installed, and then run
+Make sure you have Colima and Docker installed and configured and then run:
 
 ```shell
 docker compose up

apps/state_mediator/test/state_mediator/mqtt_mediator_test.exs

@@ -28,8 +28,8 @@ defmodule StateMediator.MqttMediatorTest do
 
   # @moduletag capture_log: true
   @opts [
-    url: "mqtt://test.mosquitto.org",
-    topic: "home/#",
+    url: "mqtt://localhost:1883",
+    topic: "home/test",
     state: __MODULE__.StateModule
   ]
 
@@ -55,6 +55,22 @@ defmodule StateMediator.MqttMediatorTest do
 
     test "are sent to the state module" do
       {:ok, _pid} = start_link(@opts)
+
+      {:ok, _client} =
+        EmqttFailover.Connection.start_link(
+          configs: [@opts[:url]],
+          handler: {EmqttFailover.ConnectionHandler.Parent, parent: self()}
+        )
+
+      assert_receive {:connected, client}, 5_000
+      Process.sleep(100)
+
+      :ok =
+        EmqttFailover.Connection.publish(client, %EmqttFailover.Message{
+          topic: @opts[:topic],
+          payload: "online"
+        })
+
       assert_receive {:updated, contents}, 5_000
       assert <<_::binary>> = contents
     end

docker-compose.yml

@@ -6,4 +6,10 @@ services:
     container_name: dynamodb-local
     ports:
       - "8000:8000"
-    working_dir: /home/dynamodblocal
+  mosquitto:
+    image: "eclipse-mosquitto:2.0"
+    container_name: mosquitto
+    ports:
+      - "1883:1883"
+    volumes:
+      - ./mosquitto:/mosquitto/config/

mosquitto/mosquitto.conf

@@ -0,0 +1,2 @@
+listener 1883
+allow_anonymous true