From 789f1510fdcf95bcaf336615b5f2e802c767b4ca Mon Sep 17 00:00:00 2001
From: Neil Menne <nhm@neilmenne.com>
Date: Mon, 25 Jun 2018 15:12:59 -0400
Subject: [PATCH] README revelation: remove redundancy

---
 README.md                       |  2 +-
 lib/maestro/aggregate/root.ex   |  8 ++++++--
 test/maestro/aggregate_test.exs | 31 +++++++++++++++++++------------
 3 files changed, 26 insertions(+), 15 deletions(-)

diff --git a/README.md b/README.md
index 3430aff..1581829 100644
--- a/README.md
+++ b/README.md
@@ -89,6 +89,6 @@ end
 
 ```elixir
 iex(1)> {:ok, id} = MyApp.Aggregate.new()
-iex(2)> :ok = MyApp.Aggregate.evaluate(id, %Maestro.Types.Command{aggregate_id: id, type: "increment_counter", data: %{}})
+iex(2)> :ok = MyApp.Aggregate.evaluate(%Maestro.Types.Command{aggregate_id: id, type: "increment_counter", data: %{}})
 iex(3)> {:ok, %{"value" => 1}} = MyApp.Aggregate.get(id)
 ```
diff --git a/lib/maestro/aggregate/root.ex b/lib/maestro/aggregate/root.ex
index 8dbdcbe..51b8082 100644
--- a/lib/maestro/aggregate/root.ex
+++ b/lib/maestro/aggregate/root.ex
@@ -87,7 +87,11 @@ defmodule Maestro.Aggregate.Root do
 
       def replay(agg_id, seq), do: call(agg_id, {:replay, seq})
 
-      def evaluate(agg_id, command), do: call(agg_id, {:eval_command, command})
+      def evaluate(%Maestro.Types.Command{} = command) do
+        call(command.aggregate_id, {:eval_command, command})
+      end
+
+      def evaluate(_), do: raise(ArgumentError, "invalid command")
 
       def snapshot(agg_id) do
         with {:ok, snap} <- call(agg_id, :get_snapshot) do
@@ -233,7 +237,7 @@ defmodule Maestro.Aggregate.Root do
   @doc """
   Evaluate the command within the aggregate's context.
   """
-  @callback evaluate(id(), command()) :: :ok | {:error, any(), stack()}
+  @callback evaluate(command()) :: :ok | {:error, any(), stack()}
 
   @doc """
   Using the aggregate root's `prepare_snapshot` function, generate and store a
diff --git a/test/maestro/aggregate_test.exs b/test/maestro/aggregate_test.exs
index 66b5087..8d9f478 100644
--- a/test/maestro/aggregate_test.exs
+++ b/test/maestro/aggregate_test.exs
@@ -34,7 +34,7 @@ defmodule Maestro.AggregateTest do
       check all agg_id <- timestamp(),
                 coms <- commands(agg_id, max_commands: 200) do
         for com <- coms do
-          :ok = SampleAggregate.evaluate(agg_id, com)
+          :ok = SampleAggregate.evaluate(com)
         end
 
         {:ok, %{"value" => value}} = SampleAggregate.get(agg_id)
@@ -51,13 +51,13 @@ defmodule Maestro.AggregateTest do
       {:ok, %{"value" => value}} = SampleAggregate.get(agg_id)
       assert value == 0
 
-      SampleAggregate.evaluate(agg_id, %Command{
+      SampleAggregate.evaluate(%Command{
         type: "increment_counter",
         aggregate_id: agg_id,
         data: %{}
       })
 
-      SampleAggregate.evaluate(agg_id, %Command{
+      SampleAggregate.evaluate(%Command{
         type: "increment_counter",
         aggregate_id: agg_id,
         data: %{}
@@ -69,7 +69,7 @@ defmodule Maestro.AggregateTest do
 
       {:ok, _pid} = SampleAggregate.start_link(agg_id)
 
-      SampleAggregate.evaluate(agg_id, %Command{
+      SampleAggregate.evaluate(%Command{
         type: "increment_counter",
         aggregate_id: agg_id,
         data: %{}
@@ -91,7 +91,7 @@ defmodule Maestro.AggregateTest do
       commands = repeat(base_command, 10)
 
       for com <- commands do
-        res = SampleAggregate.evaluate(agg_id, com)
+        res = SampleAggregate.evaluate(com)
 
         case res do
           :ok -> :ok
@@ -116,9 +116,16 @@ defmodule Maestro.AggregateTest do
         data: %{}
       }
 
-      {:error, err, _stack} = SampleAggregate.evaluate(agg_id, com)
+      {:error, err, _stack} = SampleAggregate.evaluate(com)
 
       assert err == InvalidHandlerError.exception(type: "invalid")
+
+      assert_raise(ArgumentError, fn ->
+        SampleAggregate.evaluate(%{
+          type: "increment_counter",
+          data: %{}
+        })
+      end)
     end
 
     test "handler rejected command" do
@@ -130,7 +137,7 @@ defmodule Maestro.AggregateTest do
         data: %{"do_inc" => false}
       }
 
-      {:error, err, _stack} = SampleAggregate.evaluate(agg_id, com)
+      {:error, err, _stack} = SampleAggregate.evaluate(com)
 
       assert err ==
                InvalidCommandError.exception(
@@ -147,7 +154,7 @@ defmodule Maestro.AggregateTest do
         data: %{"raise" => true}
       }
 
-      {:error, err, _stack} = SampleAggregate.evaluate(agg_id, com)
+      {:error, err, _stack} = SampleAggregate.evaluate(com)
 
       assert err ==
                ArgumentError.exception(
@@ -169,7 +176,7 @@ defmodule Maestro.AggregateTest do
         get_snapshot: fn _, _, _ ->
           raise(ConnectionError, "some")
         end do
-        {:error, err, _stack} = SampleAggregate.evaluate(agg_id, com)
+        {:error, err, _stack} = SampleAggregate.evaluate(com)
         assert err == ConnectionError.exception("some")
       end
     end
@@ -191,9 +198,9 @@ defmodule Maestro.AggregateTest do
         data: %{"name" => "sample"}
       }
 
-      :ok = SampleAggregate.evaluate(agg_id, com)
+      :ok = SampleAggregate.evaluate(com)
 
-      {:error, err, _stack} = SampleAggregate.evaluate(agg_id, com)
+      {:error, err, _stack} = SampleAggregate.evaluate(com)
 
       assert err ==
                InvalidCommandError.exception(
@@ -204,7 +211,7 @@ defmodule Maestro.AggregateTest do
 
       com_2 = Map.put(com, :aggregate_id, agg_id_2)
 
-      {:error, err, _stack} = SampleAggregate.evaluate(agg_id_2, com_2)
+      {:error, err, _stack} = SampleAggregate.evaluate(com_2)
 
       assert err.__struct__ == Ecto.ConstraintError