feat(Vehicles.Repo): get by vehicle ID

lib/vehicles/repo.ex

@@ -11,6 +11,19 @@ defmodule Vehicles.Repo do
 
   @behaviour Behaviour
 
+  @impl Behaviour
+  def get(vehicle_id) do
+    __MODULE__
+    |> :ets.select([{{vehicle_id, :_, :_, :_, :"$1"}, [], [:"$1"]}])
+    |> case do
+      [%Vehicle{} = vehicle] ->
+        vehicle
+
+      _ ->
+        nil
+    end
+  end
+
   @impl Behaviour
   def route(route_id, opts \\ []) do
     direction_id =

lib/vehicles/repo/behaviour.ex

@@ -5,6 +5,8 @@ defmodule Vehicles.Repo.Behaviour do
 
   alias Vehicles.Vehicle
 
+  @callback get(String.t()) :: Vehicle.t() | nil
+
   @callback route(String.t(), Keyword.t()) :: [Vehicle.t()]
 
   @callback trip(String.t()) :: Vehicle.t() | nil

test/vehicles/repo_test.exs

@@ -24,6 +24,17 @@ defmodule Vehicles.RepoTest do
 
   def pubsub_fn(_, "vehicles"), do: :ok
 
+  describe "get/1" do
+    test "given a vehicle ID, return the matching vehicle" do
+      id = @vehicles |> Enum.map(& &1.id) |> Faker.Util.pick()
+      assert %Vehicle{} = Repo.get(id)
+    end
+
+    test "return nil otherwise" do
+      refute Repo.get("not-in-@vehicles")
+    end
+  end
+
   describe "route/1" do
     test "given a route ID, finds vehicle statuses for that route", %{name: name} do
       assert Enum.sort(Enum.filter(@vehicles, &(&1.route_id == "86"))) ==