Initial commit

lib/equalities.ex

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+defmodule Equalities do
+  use Koans
+
+  koan "We shall contemplate truth by testing reality, via equality" do
+    assert true == true
+  end
+
+  koan "To understand reality, we must compare our expectations against reality" do
+    assert 2 == 1 + 1
+  end
+
+  koan "Some things may appear different, but be the same" do
+    assert 1 == 2 / 2
+  end
+
+  koan "Something is not equal to nothing" do
+    assert !(1 == nil)
+  end
+
+  koan "When things cannot be equal, they must be different" do
+    refute :something == 4
+  end
+end

lib/koans.ex

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+defmodule Koans do
+  defmacro koan(name, body) do
+    compiled_name = :"koan: #{name}"
+    quote do
+      def unquote(compiled_name)() do
+        try do
+          unquote(body)
+          :ok
+        rescue
+          e in ExUnit.AssertionError -> e
+        end
+      end
+    end
+  end
+
+  defmacro __using__(_) do
+    quote do
+      import Koans
+      import ExUnit.Assertions
+    end
+  end
+end

lib/lists.ex

@@ -0,0 +1,7 @@
+defmodule Lists do
+  use Koans
+
+  koan "We shall contemplate truth by testing reality, via equality" do
+    assert List.first([1, 2, 3]) == 2
+  end
+end

lib/meditate.ex

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+defmodule Mix.Tasks.Meditate do
+  use Mix.Task
+  alias IO.ANSI
+
+  @modules [
+    Equalities,
+    Lists
+  ]
+
+  def run(_) do
+    IO.puts("")
+    Enum.take_while(@modules, fn(mod) ->
+      run_module(mod) == :passed
+    end)
+  end
+
+  def run_module(module) do
+    IO.puts("Considering #{display_module(module)}...")
+
+    functions = module.__info__(:functions)
+
+    koans = Enum.map(functions, fn({name, _arity}) -> name end)
+    |> Enum.filter(&koan?/1)
+
+    passed = Enum.take_while(koans, fn(name) ->
+      run_koan(module, name) == :passed
+    end)
+
+
+    if Enum.count(koans) == Enum.count(passed) do
+      :passed
+    else
+      :failed
+    end
+  end
+
+  def run_koan(module, name) do
+    case apply(module, name, []) do
+      :ok   -> :passed
+      error ->
+        show_failure(error, module, name)
+        :failed
+    end
+  end
+
+  def show_failure(%{expr: expr}, module, name) do
+    IO.puts("")
+    IO.puts("Now meditate upon #{display_module(module)}")
+    IO.puts("---------------------------------------")
+    IO.puts("Assertion failed!")
+    IO.puts(display_koan(name))
+    IO.puts(format_red(Macro.to_string(expr)))
+  end
+
+  def format_red(str) do
+    Enum.join([ANSI.red, str, ANSI.reset], "")
+  end
+
+  defp koan?(fun_name) do
+    String.starts_with?(to_string(fun_name), "koan: ")
+  end
+
+  defp display_module(module) do
+    Module.split(module) |> List.last
+  end
+
+  defp display_koan(name) do
+    String.replace(to_string(name), "koan: ", "")
+  end
+end
+