Added Elixir Processes tests

test/elixir_processes_test.exs

@@ -0,0 +1,154 @@
+defmodule ProcessTest do
+  use ExUnit.Case
+
+  defmodule KV do
+    def start_link do
+      Task.start_link(fn -> loop(%{}) end)
+    end
+
+    defp loop(map) do
+      receive do
+        {:get, key, caller} ->
+          send(caller, Map.get(map, key))
+          loop(map)
+
+        {:put, key, value} ->
+          loop(Map.put(map, key, value))
+      end
+    end
+  end
+
+  test "spawning a process" do
+    {pid, ref} = spawn_monitor(fn -> 1 + 2 end)
+    assert_receive {:DOWN, ^ref, :process, ^pid, _reason}
+    assert Process.alive?(pid) == false
+  end
+
+  test "retrieving current process PID" do
+    pid = self()
+    assert Process.alive?(pid)
+  end
+
+  test "sending and receiving messages" do
+    send(self(), {:hello, "world"})
+
+    received_message =
+      receive do
+        {:hello, msg} -> msg
+        {:world, _msg} -> "won't match"
+      end
+
+    assert received_message == "world"
+  end
+
+  test "receiving message with timeout" do
+    result =
+      receive do
+        {:hello, msg} -> msg
+      after
+        1_000 -> "nothing after 1s"
+      end
+
+    assert result == "nothing after 1s"
+  end
+
+  test "sending messages between processes" do
+    parent = self()
+    spawn(fn -> send(parent, {:hello, self()}) end)
+
+    received_message =
+      receive do
+        {:hello, pid} -> "Got hello from #{inspect(pid)}"
+      end
+
+    assert String.starts_with?(received_message, "Got hello from #PID<")
+  end
+
+  test "process spawned with spawn/1 fails without affecting the parent process" do
+    Process.flag(:trap_exit, true)
+
+    spawn(fn ->
+      try do
+        raise "oops"
+      catch
+        _, _ -> exit(1)
+      end
+    end)
+
+    refute_receive {:EXIT, _pid, _reason}, 500
+  end
+
+  test "spawning a linked process and handling failure" do
+    Process.flag(:trap_exit, true)
+
+    spawn_link(fn ->
+      try do
+        raise "oops"
+      catch
+        _, _ -> exit(1)
+      end
+    end)
+
+    assert_receive {:EXIT, _pid, _reason}
+  end
+
+  test "task raises an exception" do
+    {pid, ref} =
+      spawn_monitor(fn ->
+        Task.start(fn ->
+          try do
+            raise "oops"
+          catch
+            _, _ -> :ok
+          end
+        end)
+      end)
+
+    assert_receive {:DOWN, ^ref, :process, ^pid, reason}
+    assert reason == :normal
+    refute_receive {:EXIT, _pid, _reason}, 500
+  end
+
+  # test "task start_link process and handling failure" do
+  #   Process.flag(:trap_exit, true)
+
+  #   Task.start_link(fn ->
+  #     try do
+  #       raise "oops"
+  #     catch
+  #       _, _ -> exit(1)
+  #     end
+  #   end)
+
+  #   assert_receive {:EXIT, _pid, _reason}
+  # end
+
+  test "creating a simple key-value store with processes" do
+    {:ok, pid} = KV.start_link()
+
+    send(pid, {:put, :hello, :world})
+    send(pid, {:get, :hello, self()})
+
+    received_value =
+      receive do
+        :world -> :world
+      end
+
+    assert received_value == :world
+  end
+
+  test "registering a process and interacting with it by name" do
+    {:ok, pid} = KV.start_link()
+    Process.register(pid, :kv)
+
+    send(:kv, {:put, :hello, :world})
+    send(:kv, {:get, :hello, self()})
+
+    received_value =
+      receive do
+        :world -> :world
+      end
+
+    assert received_value == :world
+  end
+end