Extract answers from processes.

For some reason I don't quite understand I had to rewrite
assert_receive as I was not getting failures when I was expecting them.

lib/blank_assertions.ex

@@ -27,15 +27,14 @@ defmodule BlankAssertions do
     end
   end
 
-  defmacro assert_receive(expr) do
-    if contains_blank?(expr) do
-      code = Macro.escape(expr)
-      quote do
-        raise ExUnit.AssertionError, expr: unquote(code)
-      end
+  def assert_receive(expr) do
+    if expr == :__ do
+      raise ExUnit.AssertionError, expr: expr
     else
-      quote do
-        ExUnit.Assertions.assert_receive(unquote(expr), 100)
+      receive do
+        ^expr -> true
+      after
+        100 -> flunk("No message matching #{expr} found in mailbox")
       end
     end
   end
@@ -48,10 +47,8 @@ defmodule BlankAssertions do
     ExUnit.Assertions.refute(value, opts)
   end
 
-  defmacro flunk(message \\ "Flunked!") do
-    quote do
-      assert false, message: unquote(message)
-    end
+  def flunk(message \\ "Flunked!") do
+    ExUnit.Assertions.flunk(message)
   end
 
   defp contains_blank?(expr) do

lib/koans/10_processes.ex

@@ -2,18 +2,18 @@ defmodule Processes do
   use Koans
 
   koan "tests run in a process!" do
-    assert Process.alive?(self)
+    assert Process.alive?(:__)
   end
 
   koan "can spew out information about a process" do
     information = Process.info(self)
 
-    assert information[:status] == :running
+    assert information[:status] == :__
   end
 
   koan "process can send messages to itself" do
     send self(), "hola!"
-    assert_receive "hola!"
+    assert_receive :__
   end
 
   koan "a common pattern is to include the sender in the message" do
@@ -24,7 +24,7 @@ defmodule Processes do
                  end)
 
     send pid, {:hello, self()}
-    assert_receive :how_are_you?
+    assert_receive :__
   end
 
   koan "you don't have to wait forever for messages" do
@@ -36,22 +36,20 @@ defmodule Processes do
                 end
            end)
 
-    assert_receive {:waited_too_long, "I am inpatient"}
+    assert_receive :__
   end
 
   koan "killing a process will terminate it" do
     pid = spawn(fn -> Process.exit(self(), :kill) end)
     :timer.sleep(500)
-    refute Process.alive?(pid)
+    assert Process.alive?(pid) == :__
   end
 
   koan "killing a process kills it for good" do
-    pid = spawn(fn -> receive do
-                      end
-    end)
+    pid = spawn(fn -> receive do end end)
     assert Process.alive?(pid)
     Process.exit(pid, :kill)
-    refute Process.alive?(pid)
+    assert Process.alive?(pid) == :__
   end
 
   koan "can trap a signal in a child process" do
@@ -66,8 +64,7 @@ defmodule Processes do
     wait()
     Process.exit(pid, :random_reason)
 
-    assert_receive {:exited, :random_reason}
-    refute Process.alive?(pid)
+    assert_receive :__
   end
 
   koan "quitting normally has no effect" do
@@ -75,7 +72,7 @@ defmodule Processes do
                       end
                 end)
     Process.exit(pid, :normal)
-    assert Process.alive?(pid)
+    assert Process.alive?(pid) == :__
   end
 
   koan "quititing your own process normally does terminate it though" do
@@ -84,10 +81,9 @@ defmodule Processes do
                       end
                 end)
 
-    assert Process.alive?(pid)
     send pid, :bye
     :timer.sleep(100)
-    refute Process.alive?(pid)
+    assert Process.alive?(pid) == :__
   end
 
   koan "linked processes are informed about exit signals of children when trapping those signals" do
@@ -100,7 +96,7 @@ defmodule Processes do
             end
      end)
 
-    assert_receive {:exited, :normal}
+    assert_receive :__
   end
 
   koan "monitoring processes are informed via messages without having trapping" do
@@ -112,7 +108,7 @@ defmodule Processes do
             end
      end)
 
-    assert_receive {:exited, :normal}
+    assert_receive :__
   end
 
   def wait do

test/koans_harness_test.exs

@@ -185,6 +185,25 @@ defmodule KoansHarnessTest do
     test_all(PatternMatching, answers)
   end
 
+  test "Processes" do
+    answers = [
+      self,
+      :running,
+      "hola!",
+      :how_are_you?,
+      {:waited_too_long, "I am inpatient"},
+      false,
+      false,
+      {:exited, :random_reason},
+      true,
+      false,
+      {:exited, :normal},
+      {:exited, :normal}
+      ]
+
+    test_all(Processes, answers)
+  end
+
   def test_all(module, answers) do
     module.all_koans
     |> Enum.zip(answers)