diff --git a/.formatter.exs b/.formatter.exs
new file mode 100644
index 0000000..4a806c3
--- /dev/null
+++ b/.formatter.exs
@@ -0,0 +1,3 @@
+[
+  inputs: ["{config,lib,test}/**/*.{ex,exs}"]
+]
diff --git a/lib/blanks.ex b/lib/blanks.ex
index e808b69..6e8a73e 100644
--- a/lib/blanks.ex
+++ b/lib/blanks.ex
@@ -1,6 +1,7 @@
 defmodule Blanks do
   def replace(ast, replacements) do
     replacements = List.wrap(replacements)
+
     ast
     |> Macro.prewalk(replacements, &pre/2)
     |> elem(0)
@@ -10,6 +11,7 @@ defmodule Blanks do
     {args, replacements} = Macro.prewalk(args, replacements, &pre_pin/2)
     {put_elem(node, 2, args), replacements}
   end
+
   defp pre({:___, _, _}, [first | remainder]), do: {first, remainder}
   defp pre(node, acc), do: {node, acc}
 
@@ -21,6 +23,7 @@ defmodule Blanks do
       ^unquote(var)
     end
   end
+
   defp pin(var), do: var
 
   def count(ast) do
@@ -29,16 +32,18 @@ defmodule Blanks do
     |> elem(1)
   end
 
-  defp count({:___, _, _} = node, acc), do: {node, acc+1}
+  defp count({:___, _, _} = node, acc), do: {node, acc + 1}
   defp count(node, acc), do: {node, acc}
 
   def replace_line({:__block__, meta, lines}, replacement_fn) do
-    replaced_lines = Enum.map(lines, fn(line) ->
-      replace_line(line, replacement_fn)
-    end)
+    replaced_lines =
+      Enum.map(lines, fn line ->
+        replace_line(line, replacement_fn)
+      end)
 
     {:__block__, meta, replaced_lines}
   end
+
   def replace_line(line, replacement_fn) do
     if count(line) > 0 do
       replacement_fn.(line)
diff --git a/lib/display.ex b/lib/display.ex
index 13667b5..8f2a240 100644
--- a/lib/display.ex
+++ b/lib/display.ex
@@ -17,33 +17,34 @@ defmodule Display do
   end
 
   def handle_cast(:clear_screen, state = %{clear_screen: true}) do
-    IO.puts(ANSI.clear)
-    IO.puts(ANSI.home)
+    IO.puts(ANSI.clear())
+    IO.puts(ANSI.home())
 
     {:noreply, state}
   end
+
   def handle_cast(:clear_screen, state) do
     {:noreply, state}
   end
 
   def invalid_koan(koan, modules) do
     Notifications.invalid_koan(koan, modules)
-    |> IO.puts
+    |> IO.puts()
   end
 
   def show_failure(failure, module, name) do
     format(failure, module, name)
-    |> IO.puts
+    |> IO.puts()
   end
 
   def show_compile_error(error) do
     Failure.show_compile_error(error)
-    |> IO.puts
+    |> IO.puts()
   end
 
   def congratulate do
-    Notifications.congratulate
-    |> IO.puts
+    Notifications.congratulate()
+    |> IO.puts()
   end
 
   def clear_screen do
@@ -52,9 +53,9 @@ defmodule Display do
 
   defp format(failure, module, name) do
     """
-    #{Intro.intro(module, Tracker.visited)}
+    #{Intro.intro(module, Tracker.visited())}
     Now meditate upon #{format_module(module)}
-    #{ProgressBar.progress_bar(Tracker.summarize)}
+    #{ProgressBar.progress_bar(Tracker.summarize())}
     ----------------------------------------
     #{name}
     #{Failure.format_failure(failure)}
@@ -62,6 +63,6 @@ defmodule Display do
   end
 
   defp format_module(module) do
-    Module.split(module) |> List.last
+    Module.split(module) |> List.last()
   end
 end
diff --git a/lib/display/colours.ex b/lib/display/colours.ex
index 49355b9..34e8d0b 100644
--- a/lib/display/colours.ex
+++ b/lib/display/colours.ex
@@ -5,7 +5,7 @@ defmodule Display.Paint do
   def yellow(str), do: painter().yellow(str)
 
   defp painter do
-    case Mix.env do
+    case Mix.env() do
       :test -> Display.Uncoloured
       _ -> Display.Colours
     end
@@ -15,13 +15,13 @@ end
 defmodule Display.Colours do
   alias IO.ANSI
 
-  def red(str), do: colourize(ANSI.red, str)
-  def cyan(str), do: colourize(ANSI.cyan, str)
-  def green(str), do: colourize(ANSI.green, str)
-  def yellow(str), do: colourize(ANSI.yellow, str)
+  def red(str), do: colourize(ANSI.red(), str)
+  def cyan(str), do: colourize(ANSI.cyan(), str)
+  def green(str), do: colourize(ANSI.green(), str)
+  def yellow(str), do: colourize(ANSI.yellow(), str)
 
   defp colourize(color, message) do
-    Enum.join([color, message, ANSI.reset], "")
+    Enum.join([color, message, ANSI.reset()], "")
   end
 end
 
diff --git a/lib/display/failure.ex b/lib/display/failure.ex
index 63ed22e..ced1046 100644
--- a/lib/display/failure.ex
+++ b/lib/display/failure.ex
@@ -3,12 +3,17 @@ defmodule Display.Failure do
 
   @no_value :ex_unit_no_meaningful_value
 
-  def format_failure(%{error: %ExUnit.AssertionError{expr: @no_value, message: message}, file: file, line: line}) do
+  def format_failure(%{
+        error: %ExUnit.AssertionError{expr: @no_value, message: message},
+        file: file,
+        line: line
+      }) do
     """
     #{Paint.cyan("Assertion failed in #{file}:#{line}")}
     #{Paint.red(message)}
     """
   end
+
   def format_failure(%{error: %ExUnit.AssertionError{expr: expr} = error, file: file, line: line}) do
     """
     #{Paint.cyan("Assertion failed in #{file}:#{line}")}
@@ -16,6 +21,7 @@ defmodule Display.Failure do
     """
     |> format_inequality(error)
   end
+
   def format_failure(%{error: error, file: file, line: line}) do
     """
     #{Paint.cyan("Error in #{file}:#{line}")}
@@ -26,22 +32,24 @@ defmodule Display.Failure do
   defp format_inequality(message, %{left: @no_value, right: @no_value}) do
     message
   end
+
   defp format_inequality(message, %{left: @no_value, right: match_value}) do
     """
     #{message}
-    value does not match: #{match_value |> inspect |> Paint.yellow}
+    value does not match: #{match_value |> inspect |> Paint.yellow()}
     """
   end
+
   defp format_inequality(message, %{left: left, right: right}) do
     """
     #{message}
-    left:  #{left |> inspect |> Paint.yellow}
-    right: #{right |> inspect |> Paint.yellow}
+    left:  #{left |> inspect |> Paint.yellow()}
+    right: #{right |> inspect |> Paint.yellow()}
     """
   end
 
   defp format_error(error) do
-    trace = System.stacktrace |> Enum.take(2)
+    trace = System.stacktrace() |> Enum.take(2)
     Paint.red(Exception.format(:error, error, trace))
   end
 
diff --git a/lib/display/intro.ex b/lib/display/intro.ex
index d62fd07..df36542 100644
--- a/lib/display/intro.ex
+++ b/lib/display/intro.ex
@@ -2,7 +2,7 @@ defmodule Display.Intro do
   alias Display.Paint
 
   def intro(module, modules) do
-    if not module in modules do
+    if not (module in modules) do
       show_intro(module.intro)
     else
       ""
@@ -10,7 +10,7 @@ defmodule Display.Intro do
   end
 
   def show_intro(message) do
-    message <> "\n"
-    |> Paint.green
+    (message <> "\n")
+    |> Paint.green()
   end
 end
diff --git a/lib/display/notification.ex b/lib/display/notification.ex
index a586dac..6826b22 100644
--- a/lib/display/notification.ex
+++ b/lib/display/notification.ex
@@ -15,7 +15,7 @@ defmodule Display.Notifications do
     |> Enum.map(&Atom.to_string/1)
     |> Enum.map(&name/1)
     |> Enum.join(", ")
-    |> Paint.red
+    |> Paint.red()
   end
 
   defp name("Elixir." <> module), do: module
diff --git a/lib/display/progress_bar.ex b/lib/display/progress_bar.ex
index c7693df..36d3123 100644
--- a/lib/display/progress_bar.ex
+++ b/lib/display/progress_bar.ex
@@ -1,5 +1,4 @@
 defmodule Display.ProgressBar do
-
   @progress_bar_length 30
 
   def progress_bar(%{current: current, total: total}) do
@@ -9,11 +8,12 @@ defmodule Display.ProgressBar do
   end
 
   defp calculate_progress(current, total) do
-    round( (current/total) * @progress_bar_length)
+    round(current / total * @progress_bar_length)
   end
 
   defp build_arrow(0), do: ""
+
   defp build_arrow(length) do
-    String.duplicate("=", length-1) <> ">"
+    String.duplicate("=", length - 1) <> ">"
   end
 end
diff --git a/lib/execute.ex b/lib/execute.ex
index ee59247..4ddebae 100644
--- a/lib/execute.ex
+++ b/lib/execute.ex
@@ -1,6 +1,6 @@
 defmodule Execute do
-  def run_module(module, callback \\ fn(_result, _module, _koan) -> nil end) do
-    Enum.reduce_while(module.all_koans, :passed, fn(koan, _) ->
+  def run_module(module, callback \\ fn _result, _module, _koan -> nil end) do
+    Enum.reduce_while(module.all_koans, :passed, fn koan, _ ->
       module
       |> run_koan(koan)
       |> hook(module, koan, callback)
@@ -24,7 +24,7 @@ defmodule Execute do
 
   def listen_for_result(module, name) do
     receive do
-      :ok   -> :passed
+      :ok -> :passed
       %{error: _} = failure -> {:failed, failure, module, name}
       _ -> listen_for_result(module, name)
     end
@@ -32,23 +32,25 @@ defmodule Execute do
 
   defp exec(module, name, args, parent) do
     result = apply(module, name, args)
-    send parent, expand(result, module)
+    send(parent, expand(result, module))
     Process.exit(self(), :kill)
   end
 
   defp expand(:ok, _), do: :ok
+
   defp expand(error, module) do
-    {file, line} = System.stacktrace
-      |> Enum.drop_while(&!in_koan?(&1, module))
-      |> List.first
+    {file, line} =
+      System.stacktrace()
+      |> Enum.drop_while(&(!in_koan?(&1, module)))
+      |> List.first()
       |> extract_file_and_line
 
-      %{error: error, file: file, line: line}
+    %{error: error, file: file, line: line}
   end
 
   defp in_koan?({module, _, _, _}, koan), do: module == koan
 
   defp extract_file_and_line({_, _, _, [file: file, line: line]}) do
-   {file, line}
+    {file, line}
   end
 end
diff --git a/lib/koans.ex b/lib/koans.ex
index 2b3ed68..31fb9de 100644
--- a/lib/koans.ex
+++ b/lib/koans.ex
@@ -29,8 +29,10 @@ defmodule Koans do
   end
 
   defmacro generate_test_method(_name, 0, _body), do: false
+
   defmacro generate_test_method(name, 1, body) do
     single_var = Blanks.replace(body, Macro.var(:answer, __MODULE__))
+
     quote do
       def unquote(name)(answer) do
         try do
@@ -42,8 +44,11 @@ defmodule Koans do
       end
     end
   end
+
   defmacro generate_test_method(name, number_of_args, body) do
-    answer_vars = for id <- 1..number_of_args, do: Macro.var(String.to_atom("answer#{id}"), __MODULE__)
+    answer_vars =
+      for id <- 1..number_of_args, do: Macro.var(String.to_atom("answer#{id}"), __MODULE__)
+
     multi_var = Blanks.replace(body, answer_vars)
 
     quote do
@@ -60,12 +65,12 @@ defmodule Koans do
 
   defp blank_line_replacement({:assert, _meta, [expr]}) do
     code = Macro.escape(expr)
-    quote do: raise ExUnit.AssertionError, expr: unquote(code)
+    quote do: raise(ExUnit.AssertionError, expr: unquote(code))
   end
 
   defp blank_line_replacement(line) do
     code = Macro.escape(line)
-    quote do: raise ExUnit.AssertionError, expr: unquote(code)
+    quote do: raise(ExUnit.AssertionError, expr: unquote(code))
   end
 
   defmacro __using__(_opts) do
@@ -83,6 +88,7 @@ defmodule Koans do
 
   defmacro __before_compile__(env) do
     koans = koans(env)
+
     quote do
       def all_koans do
         unquote(koans)
@@ -95,6 +101,6 @@ defmodule Koans do
   defp koans(env) do
     env.module
     |> Module.get_attribute(:koans)
-    |> Enum.reverse
+    |> Enum.reverse()
   end
 end
diff --git a/lib/koans/01_equalities.ex b/lib/koans/01_equalities.ex
index 121c606..142ed7c 100644
--- a/lib/koans/01_equalities.ex
+++ b/lib/koans/01_equalities.ex
@@ -1,7 +1,7 @@
 defmodule Equalities do
   use Koans
 
-  @intro  """
+  @intro """
   Welcome to the Elixir koans.
   Let these be your first humble steps towards learning a new language.
 
diff --git a/lib/koans/04_atoms.ex b/lib/koans/04_atoms.ex
index 27d6cfb..a6a3199 100644
--- a/lib/koans/04_atoms.ex
+++ b/lib/koans/04_atoms.ex
@@ -11,12 +11,12 @@ defmodule Atoms do
   koan "It is surprising to find out that booleans are atoms" do
     assert is_atom(true) == ___
     assert is_boolean(false) == ___
-    assert :true == ___
-    assert :false == ___
+    assert true == ___
+    assert false == ___
   end
 
   koan "Like booleans, the nil value is also an atom" do
     assert is_atom(nil) == ___
-    assert :nil == ___
+    assert nil == ___
   end
 end
diff --git a/lib/koans/08_maps.ex b/lib/koans/08_maps.ex
index 4631097..96e8a78 100644
--- a/lib/koans/08_maps.ex
+++ b/lib/koans/08_maps.ex
@@ -6,13 +6,11 @@ defmodule Maps do
   @person %{
     first_name: "Jon",
     last_name: "Snow",
-    age: 27,
+    age: 27
   }
 
   koan "Maps represent structured data, like a person" do
-    assert @person == %{first_name: ___,
-                        last_name: "Snow",
-                        age: 27 }
+    assert @person == %{first_name: ___, last_name: "Snow", age: 27}
   end
 
   koan "Fetching a value returns a tuple with ok when it exists" do
diff --git a/lib/koans/10_structs.ex b/lib/koans/10_structs.ex
index 965197a..55bdb03 100644
--- a/lib/koans/10_structs.ex
+++ b/lib/koans/10_structs.ex
@@ -49,7 +49,7 @@ defmodule Structs do
 
   koan "Use the update_in macro to modify a nested value" do
     airline = %Airline{plane: %Plane{maker: :boeing, passengers: 200}}
-    assert update_in(airline.plane.passengers, fn(x) -> (x + 2) end) == ___
+    assert update_in(airline.plane.passengers, fn x -> x + 2 end) == ___
   end
 
   koan "Use the put_in macro with atoms to replace a nested value in a non-struct" do
diff --git a/lib/koans/11_sigils.ex b/lib/koans/11_sigils.ex
index 4f28cee..b297f56 100644
--- a/lib/koans/11_sigils.ex
+++ b/lib/koans/11_sigils.ex
@@ -17,7 +17,7 @@ defmodule Sigils do
   end
 
   koan "The lowercase ~s sigil supports string interpolation" do
-    assert ~s[1 + 1 = #{1+1}] == ___
+    assert ~s[1 + 1 = #{1 + 1}] == ___
   end
 
   koan "The ~S sigil is similar to ~s but doesn't do interpolation" do
@@ -29,7 +29,7 @@ defmodule Sigils do
   end
 
   koan "The ~w sigil also allows interpolation" do
-    assert ~w(Hello 1#{1+1}3) == ___
+    assert ~w(Hello 1#{1 + 1}3) == ___
   end
 
   koan "The ~W sigil behaves to ~w as ~S behaves to ~s" do
diff --git a/lib/koans/12_pattern_matching.ex b/lib/koans/12_pattern_matching.ex
index 95293f7..303b08c 100644
--- a/lib/koans/12_pattern_matching.ex
+++ b/lib/koans/12_pattern_matching.ex
@@ -41,7 +41,7 @@ defmodule PatternMatching do
 
   koan "Lists must match exactly" do
     assert_raise ___, fn ->
-      [a, b] = [1,2,3]
+      [a, b] = [1, 2, 3]
     end
   end
 
@@ -71,9 +71,9 @@ defmodule PatternMatching do
 
   koan "And they will only run the code that matches the argument" do
     name = fn
-      ("duck")  -> "Donald"
-      ("mouse") -> "Mickey"
-      (_other)  -> "I need a name!"
+      "duck" -> "Donald"
+      "mouse" -> "Mickey"
+      _other -> "I need a name!"
     end
 
     assert name.("mouse") == ___
@@ -84,10 +84,11 @@ defmodule PatternMatching do
   koan "Errors are shaped differently than successful results" do
     dog = %{type: "dog"}
 
-    result = case Map.fetch(dog, :type) do
-      {:ok, value} -> value
-      :error -> "not present"
-    end
+    result =
+      case Map.fetch(dog, :type) do
+        {:ok, value} -> value
+        :error -> "not present"
+      end
 
     assert result == ___
   end
@@ -133,10 +134,11 @@ defmodule PatternMatching do
     pinned_variable = 1
 
     example = fn
-      (^pinned_variable) -> "The number One"
-      (2) -> "The number Two"
-      (number) -> "The number #{number}"
+      ^pinned_variable -> "The number One"
+      2 -> "The number Two"
+      number -> "The number #{number}"
     end
+
     assert example.(1) == ___
     assert example.(2) == ___
     assert example.(3) == ___
@@ -144,17 +146,20 @@ defmodule PatternMatching do
 
   koan "Pinning works anywhere one would match, including 'case'" do
     pinned_variable = 1
-    result = case 1 do
-               ^pinned_variable -> "same"
-               other -> "different #{other}"
-             end
+
+    result =
+      case 1 do
+        ^pinned_variable -> "same"
+        other -> "different #{other}"
+      end
 
     assert result == ___
   end
 
   koan "Trying to rebind a pinned variable will result in an error" do
     a = 1
-    assert_raise MatchError, fn() ->
+
+    assert_raise MatchError, fn ->
       ^a = ___
     end
   end
diff --git a/lib/koans/13_functions.ex b/lib/koans/13_functions.ex
index eb349de..c20a478 100644
--- a/lib/koans/13_functions.ex
+++ b/lib/koans/13_functions.ex
@@ -12,6 +12,7 @@ defmodule Functions do
   end
 
   def multiply(a, b), do: a * b
+
   koan "Single line functions are cool, but mind the comma and the colon!" do
     assert 6 == multiply(2, ___)
   end
@@ -41,8 +42,8 @@ defmodule Functions do
     assert sum_up(1) == ___
   end
 
-  def bigger(a,b) when a > b, do: "#{a} is bigger than #{b}"
-  def bigger(a,b) when a <= b, do: "#{a} is not bigger than #{b}"
+  def bigger(a, b) when a > b, do: "#{a} is bigger than #{b}"
+  def bigger(a, b) when a <= b, do: "#{a} is not bigger than #{b}"
 
   koan "Intricate guards are possible, but be mindful of the reader" do
     assert bigger(10, 5) == ___
@@ -58,13 +59,13 @@ defmodule Functions do
   end
 
   koan "Little anonymous functions are common, and called with a dot" do
-    multiply = fn (a,b) -> a * b end
-    assert multiply.(2,3) == ___
+    multiply = fn a, b -> a * b end
+    assert multiply.(2, 3) == ___
   end
 
   koan "You can even go shorter, by using capture syntax `&()` and positional arguments" do
     multiply = &(&1 * &2)
-    assert multiply.(2,3) == ___
+    assert multiply.(2, 3) == ___
   end
 
   koan "Prefix a string with & to build a simple anonymous greet function" do
@@ -77,7 +78,7 @@ defmodule Functions do
     assert three_times.("foo") == ___
   end
 
-  def times_five_and_then(number, fun), do: fun.(number*5)
+  def times_five_and_then(number, fun), do: fun.(number * 5)
   def square(number), do: number * number
 
   koan "You can pass functions around as arguments. Place an '&' before the name and state the arity" do
@@ -90,10 +91,11 @@ defmodule Functions do
   end
 
   koan "The result of a function can be piped into another function as its first argument" do
-    result = "full-name"
-            |> String.split("-")
-            |> Enum.map(&String.capitalize/1)
-            |> Enum.join(" ")
+    result =
+      "full-name"
+      |> String.split("-")
+      |> Enum.map(&String.capitalize/1)
+      |> Enum.join(" ")
 
     assert result == ___
   end
diff --git a/lib/koans/14_enums.ex b/lib/koans/14_enums.ex
index ed8683a..78525cd 100644
--- a/lib/koans/14_enums.ex
+++ b/lib/koans/14_enums.ex
@@ -12,12 +12,14 @@ defmodule Enums do
   end
 
   def less_than_five?(n), do: n < 5
+
   koan "Elements can have a lot in common" do
     assert Enum.all?([1, 2, 3], &less_than_five?/1) == ___
     assert Enum.all?([4, 6, 8], &less_than_five?/1) == ___
   end
 
   def even?(n), do: rem(n, 2) == 0
+
   koan "Sometimes you just want to know if there are any elements fulfilling a condition" do
     assert Enum.any?([1, 2, 3], &even?/1) == ___
     assert Enum.any?([1, 3, 5], &even?/1) == ___
@@ -30,6 +32,7 @@ defmodule Enums do
   end
 
   def multiply_by_ten(n), do: 10 * n
+
   koan "Map converts each element of a list by running some function with it" do
     assert Enum.map([1, 2, 3], &multiply_by_ten/1) == ___
   end
@@ -67,6 +70,7 @@ defmodule Enums do
   end
 
   def divisible_by_five?(n), do: rem(n, 5) == 0
+
   koan "...but you don't quite find it..." do
     assert Enum.find([1, 2, 3], &divisible_by_five?/1) == ___
   end
@@ -76,6 +80,6 @@ defmodule Enums do
   end
 
   koan "Collapse an entire list of elements down to a single one by repeating a function." do
-    assert Enum.reduce([1, 2, 3], 0, fn(element, accumulator) -> element + accumulator end) == ___
+    assert Enum.reduce([1, 2, 3], 0, fn element, accumulator -> element + accumulator end) == ___
   end
 end
diff --git a/lib/koans/15_processes.ex b/lib/koans/15_processes.ex
index 6093719..3ec534c 100644
--- a/lib/koans/15_processes.ex
+++ b/lib/koans/15_processes.ex
@@ -18,9 +18,11 @@ defmodule Processes do
   end
 
   koan "New processes are spawned functions" do
-    value = spawn(fn -> receive do
-                      end
-                end)
+    value =
+      spawn(fn ->
+        receive do
+        end
+      end)
 
     assert is_pid(value) == ___
   end
@@ -39,7 +41,7 @@ defmodule Processes do
   end
 
   koan "Processes can send and receive messages" do
-    send self(), "hola!"
+    send(self(), "hola!")
 
     receive do
       msg -> assert msg == ___
@@ -58,8 +60,8 @@ defmodule Processes do
   end
 
   koan "Received messages are queued, first in first out" do
-    send self(), "hola!"
-    send self(), "como se llama?"
+    send(self(), "hola!")
+    send(self(), "como se llama?")
 
     assert_receive ___
     assert_receive ___
@@ -68,20 +70,20 @@ defmodule Processes do
   koan "A common pattern is to include the sender in the message, so that it can reply" do
     greeter = fn ->
       receive do
-        {:hello, sender} -> send sender, :how_are_you?
+        {:hello, sender} -> send(sender, :how_are_you?)
       end
     end
 
     pid = spawn(greeter)
 
-    send pid, {:hello, self()}
+    send(pid, {:hello, self()})
     assert_receive ___
   end
 
   def yelling_echo_loop do
     receive do
       {caller, value} ->
-        send caller, String.upcase(value)
+        send(caller, String.upcase(value))
         yelling_echo_loop()
     end
   end
@@ -89,18 +91,19 @@ defmodule Processes do
   koan "Use tail recursion to receive multiple messages" do
     pid = spawn_link(&yelling_echo_loop/0)
 
-    send pid, {self(), "o"}
+    send(pid, {self(), "o"})
     assert_receive ___
 
-    send pid, {self(), "hai"}
+    send(pid, {self(), "hai"})
     assert_receive ___
   end
 
   def state(value) do
     receive do
       {caller, :get} ->
-        send caller, value
+        send(caller, value)
         state(value)
+
       {caller, :set, new_value} ->
         state(new_value)
     end
@@ -108,38 +111,45 @@ defmodule Processes do
 
   koan "Processes can be used to hold state" do
     initial_state = "foo"
-    pid = spawn(fn ->
-      state(initial_state)
-    end)
 
-    send pid, {self(), :get}
+    pid =
+      spawn(fn ->
+        state(initial_state)
+      end)
+
+    send(pid, {self(), :get})
     assert_receive ___
 
-    send pid, {self(), :set, "bar"}
-    send pid, {self(), :get}
+    send(pid, {self(), :set, "bar"})
+    send(pid, {self(), :get})
     assert_receive ___
   end
 
   koan "Waiting for a message can get boring" do
     parent = self()
-    spawn(fn -> receive do
-                after
-                  5 -> send parent, {:waited_too_long, "I am impatient"}
-                end
-           end)
+
+    spawn(fn ->
+      receive do
+      after
+        5 -> send(parent, {:waited_too_long, "I am impatient"})
+      end
+    end)
 
     assert_receive ___
   end
 
   koan "Trapping will allow you to react to someone terminating the process" do
     parent = self()
-    pid = spawn(fn ->
-                      Process.flag(:trap_exit, true)
-                      send parent, :ready
-                      receive do
-                        {:EXIT, _pid, reason} -> send parent, {:exited, reason}
-                      end
-              end)
+
+    pid =
+      spawn(fn ->
+        Process.flag(:trap_exit, true)
+        send(parent, :ready)
+
+        receive do
+          {:EXIT, _pid, reason} -> send(parent, {:exited, reason})
+        end
+      end)
 
     receive do
       :ready -> true
diff --git a/lib/koans/16_tasks.ex b/lib/koans/16_tasks.ex
index 4852a32..c32837c 100644
--- a/lib/koans/16_tasks.ex
+++ b/lib/koans/16_tasks.ex
@@ -10,23 +10,26 @@ defmodule Tasks do
   end
 
   koan "If you don't need a result, use start_link/1" do
-    {result, _pid} = Task.start_link(fn -> 1+1 end)
+    {result, _pid} = Task.start_link(fn -> 1 + 1 end)
     assert result == ___
   end
 
   koan "Yield returns nil if the task isn't done yet" do
-    handle = Task.async(fn ->
-                             :timer.sleep(100)
-                             3 * 3
-                         end)
+    handle =
+      Task.async(fn ->
+        :timer.sleep(100)
+        3 * 3
+      end)
+
     assert Task.yield(handle, 10) == ___
   end
 
   koan "Tasks can be aborted with shutdown" do
-    handle = Task.async(fn ->
-                             :timer.sleep(100)
-                             3 * 3
-                         end)
+    handle =
+      Task.async(fn ->
+        :timer.sleep(100)
+        3 * 3
+      end)
 
     %Task{pid: pid} = handle
     Task.shutdown(handle)
@@ -41,10 +44,11 @@ defmodule Tasks do
   end
 
   koan "You can yield to multiple tasks at once and extract the results" do
-    squares = [1, 2, 3, 4]
-             |> Enum.map(fn(number) -> Task.async(fn -> number * number end) end)
-             |> Task.yield_many(100)
-             |> Enum.map(fn({_task,{:ok, result}}) -> result end)
+    squares =
+      [1, 2, 3, 4]
+      |> Enum.map(fn number -> Task.async(fn -> number * number end) end)
+      |> Task.yield_many(100)
+      |> Enum.map(fn {_task, {:ok, result}} -> result end)
 
     assert squares == ___
   end
diff --git a/lib/koans/17_agents.ex b/lib/koans/17_agents.ex
index eede5a8..ec0ce28 100644
--- a/lib/koans/17_agents.ex
+++ b/lib/koans/17_agents.ex
@@ -5,36 +5,38 @@ defmodule Agents do
 
   koan "Agents maintain state, so you can ask them about it" do
     {:ok, pid} = Agent.start_link(fn -> "Hi there" end)
-    assert Agent.get(pid, &(&1)) == ___
+    assert Agent.get(pid, & &1) == ___
   end
 
   koan "Agents may also be named so that you don't have to keep the pid around" do
     Agent.start_link(fn -> "Why hello" end, name: AgentSmith)
-    assert Agent.get(AgentSmith, &(&1)) == ___
+    assert Agent.get(AgentSmith, & &1) == ___
   end
 
   koan "Update to update the state" do
-    Agent.start_link(fn() -> "Hi there" end, name: __MODULE__)
+    Agent.start_link(fn -> "Hi there" end, name: __MODULE__)
 
-    Agent.update(__MODULE__, fn(old) ->
+    Agent.update(__MODULE__, fn old ->
       String.upcase(old)
     end)
-    assert Agent.get(__MODULE__, &(&1)) == ___
+
+    assert Agent.get(__MODULE__, & &1) == ___
   end
 
   koan "Use get_and_update when you need to read and change a value in one go" do
-    Agent.start_link(fn() -> ["Milk"] end, name: __MODULE__)
+    Agent.start_link(fn -> ["Milk"] end, name: __MODULE__)
 
-    old_list = Agent.get_and_update(__MODULE__, fn(old) ->
-      {old, ["Bread" | old]}
-    end)
+    old_list =
+      Agent.get_and_update(__MODULE__, fn old ->
+        {old, ["Bread" | old]}
+      end)
 
     assert old_list == ___
-    assert Agent.get(__MODULE__, &(&1)) == ___
+    assert Agent.get(__MODULE__, & &1) == ___
   end
 
   koan "Somebody has to switch off the light at the end of the day" do
-    {:ok, pid} = Agent.start_link(fn() -> ["Milk"] end, name: __MODULE__)
+    {:ok, pid} = Agent.start_link(fn -> ["Milk"] end, name: __MODULE__)
 
     Agent.stop(__MODULE__)
 
diff --git a/lib/koans/18_genservers.ex b/lib/koans/18_genservers.ex
index 0738e10..efaf432 100644
--- a/lib/koans/18_genservers.ex
+++ b/lib/koans/18_genservers.ex
@@ -46,7 +46,7 @@ defmodule GenServers do
     # GenServer implementation
 
     def handle_call(:get_password, _from, current_password) do
-     {:reply, current_password, current_password}
+      {:reply, current_password, current_password}
     end
 
     def handle_call(:get_manufacturer, _from, current_state) do
@@ -73,6 +73,7 @@ defmodule GenServers do
       case password do
         password when password === current_password ->
           {:reply, {:ok, "Laptop unlocked!"}, current_password}
+
         _ ->
           {:reply, {:error, "Incorrect password!"}, current_password}
       end
@@ -82,6 +83,7 @@ defmodule GenServers do
       case old_password do
         old_password when old_password == current_password ->
           {:noreply, new_password}
+
         _ ->
           {:noreply, current_password}
       end
@@ -147,7 +149,7 @@ defmodule GenServers do
     {_, response} = Laptop.unlock("EL!73")
     assert response == ___
 
-    {_, response} = Laptop.owner_name
+    {_, response} = Laptop.owner_name()
     assert response == ___
   end
 end
diff --git a/lib/koans/19_protocols.ex b/lib/koans/19_protocols.ex
index 8f9552d..21f9836 100644
--- a/lib/koans/19_protocols.ex
+++ b/lib/koans/19_protocols.ex
@@ -3,7 +3,7 @@ defmodule Protocols do
 
   @intro "Want to follow the rules? Adhere to the protocol!"
 
-  defprotocol School, do: def enroll(person)
+  defprotocol(School, do: def(enroll(person)))
 
   defimpl School, for: Any do
     def enroll(_) do
@@ -16,9 +16,9 @@ defmodule Protocols do
     defstruct name: ""
   end
 
-  defmodule Musician, do: defstruct name: "", instrument: ""
-  defmodule Dancer,  do: defstruct name: "", dance_style: ""
-  defmodule Baker, do: defstruct name: ""
+  defmodule(Musician, do: defstruct(name: "", instrument: ""))
+  defmodule(Dancer, do: defstruct(name: "", dance_style: ""))
+  defmodule(Baker, do: defstruct(name: ""))
 
   defimpl School, for: Musician do
     def enroll(musician) do
diff --git a/lib/meditate.ex b/lib/meditate.ex
index ee35ebf..cb06c2d 100644
--- a/lib/meditate.ex
+++ b/lib/meditate.ex
@@ -9,10 +9,11 @@ defmodule Mix.Tasks.Meditate do
 
     {parsed, _, _} = OptionParser.parse(args)
 
-    modules = parsed
-    |> initial_module
-    |> ok?
-    |> Runner.modules_to_run
+    modules =
+      parsed
+      |> initial_module
+      |> ok?
+      |> Runner.modules_to_run()
 
     Tracker.set_total(modules)
     Tracker.notify_on_complete(self())
@@ -26,7 +27,7 @@ defmodule Mix.Tasks.Meditate do
 
   defp initial_module(parsed) do
     name = Keyword.get(parsed, :koan, "Equalities")
-    String.to_atom("Elixir."<> name)
+    String.to_atom("Elixir." <> name)
   end
 
   defp set_clear_screen(parsed) do
@@ -39,7 +40,7 @@ defmodule Mix.Tasks.Meditate do
     if Runner.koan?(koan) do
       koan
     else
-      Display.invalid_koan(koan, Runner.modules)
+      Display.invalid_koan(koan, Runner.modules())
       exit(:normal)
     end
   end
diff --git a/lib/runner.ex b/lib/runner.ex
index ba28306..7bdff27 100644
--- a/lib/runner.ex
+++ b/lib/runner.ex
@@ -13,7 +13,8 @@ defmodule Runner do
 
     modules
     |> Stream.map(&(&1.module_info |> get_in([:compile, :source])))
-    |> Stream.map(&to_string/1)  # Paths are charlists
+    # Paths are charlists
+    |> Stream.map(&to_string/1)
     |> Stream.zip(modules)
     |> Stream.filter(fn {_path, mod} -> koan?(mod) end)
     |> Stream.map(fn {path, mod} -> {path_to_number(path), mod} end)
@@ -74,6 +75,7 @@ defmodule Runner do
     Display.show_failure(error, module, name)
     :failed
   end
+
   defp display(_), do: :passed
 
   defp flush do
diff --git a/lib/tracker.ex b/lib/tracker.ex
index f31b211..c02885c 100644
--- a/lib/tracker.ex
+++ b/lib/tracker.ex
@@ -2,9 +2,9 @@ defmodule Tracker do
   alias __MODULE__
 
   defstruct total: 0,
-    koans: MapSet.new(),
-    visited_modules: MapSet.new(),
-    on_complete: :noop
+            koans: MapSet.new(),
+            visited_modules: MapSet.new(),
+            on_complete: :noop
 
   def start_link do
     Agent.start_link(fn -> %Tracker{} end, name: __MODULE__)
@@ -15,15 +15,17 @@ defmodule Tracker do
   end
 
   def set_total(modules) do
-    total = modules
-    |> Enum.flat_map(&(&1.all_koans))
-    |> Enum.count
+    total =
+      modules
+      |> Enum.flat_map(& &1.all_koans)
+      |> Enum.count()
 
     Agent.update(__MODULE__, fn _ -> %Tracker{total: total} end)
   end
 
   def completed(module, koan) do
     Agent.update(__MODULE__, &mark_koan_completed(&1, module, koan))
+
     if complete?() do
       Agent.cast(__MODULE__, fn state ->
         send(state.on_complete, {self(), :complete})
@@ -34,14 +36,18 @@ defmodule Tracker do
 
   def wait_until_complete() do
     pid = Process.whereis(Tracker)
+
     receive do
       {^pid, :complete} -> :ok
     end
   end
 
   defp mark_koan_completed(state, module, koan) do
-    %{state | koans: MapSet.put(state.koans, koan),
-       visited_modules: MapSet.put(state.visited_modules, module)}
+    %{
+      state
+      | koans: MapSet.put(state.koans, koan),
+        visited_modules: MapSet.put(state.visited_modules, module)
+    }
   end
 
   def visited do
@@ -54,7 +60,7 @@ defmodule Tracker do
   end
 
   def summarize do
-    state = Agent.get(__MODULE__, &(&1))
+    state = Agent.get(__MODULE__, & &1)
 
     %{
       total: state.total,
diff --git a/lib/watcher.ex b/lib/watcher.ex
index 689652d..a8a683c 100644
--- a/lib/watcher.ex
+++ b/lib/watcher.ex
@@ -2,7 +2,7 @@ defmodule Watcher do
   use GenServer
 
   def start_link() do
-    GenServer.start_link(__MODULE__, [dirs: ["lib/koans"]])
+    GenServer.start_link(__MODULE__, dirs: ["lib/koans"])
   end
 
   def init(args) do
@@ -11,10 +11,11 @@ defmodule Watcher do
     {:ok, %{watcher_pid: watcher_pid}}
   end
 
-  def handle_info({:file_event, watcher_pid, {path, events}}, %{watcher_pid: watcher_pid}=state) do
+  def handle_info({:file_event, watcher_pid, {path, events}}, %{watcher_pid: watcher_pid} = state) do
     if Enum.member?(events, :modified) do
       path |> normalize |> reload
     end
+
     {:noreply, state}
   end
 
@@ -22,11 +23,11 @@ defmodule Watcher do
     if Path.extname(file) == ".ex" do
       try do
         file
-        |> Code.load_file
-        |> Enum.map(&(elem(&1, 0)))
+        |> Code.load_file()
+        |> Enum.map(&elem(&1, 0))
         |> Enum.find(&Runner.koan?/1)
-        |> Runner.modules_to_run
-        |> Runner.run
+        |> Runner.modules_to_run()
+        |> Runner.run()
       rescue
         e -> Display.show_compile_error(e)
       end
diff --git a/test/blanks_test.exs b/test/blanks_test.exs
index e615f17..74fef77 100644
--- a/test/blanks_test.exs
+++ b/test/blanks_test.exs
@@ -8,30 +8,32 @@ defmodule BlanksTest do
   end
 
   test "Work with multiple different replacements" do
-    [koan | _] = SampleKoan.all_koans
-    assert :ok == apply(SampleKoan, koan, [{:multiple, [3,4]}])
+    [koan | _] = SampleKoan.all_koans()
+    assert :ok == apply(SampleKoan, koan, [{:multiple, [3, 4]}])
   end
 
   test "complex example" do
-    ast = quote do: assert true == ___
+    ast = quote do: assert(true == ___)
 
-    assert Blanks.replace(ast, true) == quote(do: assert true == true)
+    assert Blanks.replace(ast, true) == quote(do: assert(true == true))
   end
 
   test "multiple arguments" do
-    ast = quote do: assert ___ == ___
+    ast = quote do: assert(___ == ___)
 
-    assert Blanks.replace(ast, [true, false]) == quote(do: assert true == false)
+    assert Blanks.replace(ast, [true, false]) == quote(do: assert(true == false))
   end
 
   test "pins variables in assert_receive replacement" do
-    ast = quote do: assert_receive ___
-    assert Blanks.replace(ast, Macro.var(:answer, __MODULE__)) == quote(do: assert_receive ^answer)
+    ast = quote do: assert_receive(___)
+
+    assert Blanks.replace(ast, Macro.var(:answer, __MODULE__)) ==
+             quote(do: assert_receive(^answer))
   end
 
   test "does not pin values in assert_receive replacement" do
-    ast = quote do: assert_receive ___
-    assert Blanks.replace(ast, :lolwat) == quote(do: assert_receive :lolwat)
+    ast = quote do: assert_receive(___)
+    assert Blanks.replace(ast, :lolwat) == quote(do: assert_receive(:lolwat))
   end
 
   test "counts simple blanks" do
@@ -41,41 +43,46 @@ defmodule BlanksTest do
   end
 
   test "counts multiple blanks" do
-    ast = quote do: assert ___ == ___
+    ast = quote do: assert(___ == ___)
 
     assert Blanks.count(ast) == 2
   end
 
   test "replaces whole line containing blank" do
-    ast = quote do
-      1 + 2
-      2 + ___
-    end
+    ast =
+      quote do
+        1 + 2
+        2 + ___
+      end
 
-    expected_result = quote do
-      1 + 2
-      true
-    end
+    expected_result =
+      quote do
+        1 + 2
+        true
+      end
 
-    actual_result = Blanks.replace_line(ast, fn(_) -> true end)
+    actual_result = Blanks.replace_line(ast, fn _ -> true end)
 
     assert actual_result == expected_result
   end
 
   test "replacement fn can access line" do
-    ast = quote do
-      1 + 2
-      2 + ___
-    end
+    ast =
+      quote do
+        1 + 2
+        2 + ___
+      end
 
-    expected_result = quote do
-      1 + 2
-      some_fun(2 + ___)
-    end
+    expected_result =
+      quote do
+        1 + 2
+        some_fun(2 + ___)
+      end
 
-    actual_result = Blanks.replace_line(ast, fn(line) ->
-      quote do: some_fun(unquote(line))
-    end)
+    actual_result =
+      Blanks.replace_line(ast, fn line ->
+        quote do: some_fun(unquote(line))
+      end)
 
     assert actual_result == expected_result
   end
diff --git a/test/display/failure_test.exs b/test/display/failure_test.exs
index 1962d6e..bea195e 100644
--- a/test/display/failure_test.exs
+++ b/test/display/failure_test.exs
@@ -18,39 +18,39 @@ defmodule FailureTests do
     error = error(%ExUnit.AssertionError{expr: quote(do: :lol == :wat), left: :lol, right: :wat})
 
     assert Failure.format_failure(error) == """
-                                            Assertion failed in some_file.ex:42
-                                            :lol == :wat
+           Assertion failed in some_file.ex:42
+           :lol == :wat
 
-                                            left:  :lol
-                                            right: :wat
-                                            """
+           left:  :lol
+           right: :wat
+           """
   end
 
   test "match failure" do
-    error = error(%ExUnit.AssertionError{expr: quote(do: match?(:lol,:wat)), right: :wat})
+    error = error(%ExUnit.AssertionError{expr: quote(do: match?(:lol, :wat)), right: :wat})
 
     assert Failure.format_failure(error) == """
-                                            Assertion failed in some_file.ex:42
-                                            match?(:lol, :wat)
+           Assertion failed in some_file.ex:42
+           match?(:lol, :wat)
 
-                                            value does not match: :wat
-                                            """
+           value does not match: :wat
+           """
   end
 
   test "only offending lines are displayed for errors" do
-    [koan] = SingleArity.all_koans
-    error  = apply(SingleArity, koan, []) |> error()
+    [koan] = SingleArity.all_koans()
+    error = apply(SingleArity, koan, []) |> error()
 
     assert Failure.format_failure(error) == """
-    Assertion failed in some_file.ex:42\nmatch?(:foo, ___)
-    """
+           Assertion failed in some_file.ex:42\nmatch?(:foo, ___)
+           """
   end
 
   defp error(error) do
     %{
       error: error,
       file: "some_file.ex",
-      line:  42
+      line: 42
     }
   end
 end
diff --git a/test/display/notification_test.exs b/test/display/notification_test.exs
index debbdb8..df0dd8d 100644
--- a/test/display/notification_test.exs
+++ b/test/display/notification_test.exs
@@ -3,7 +3,7 @@ defmodule NotificationTest do
   alias Display.Notifications
 
   test "shows possible koans when a koan can not be found" do
-    message  = Notifications.invalid_koan(SampleKoan, [PassingKoan])
+    message = Notifications.invalid_koan(SampleKoan, [PassingKoan])
     assert message == "Did not find koan SampleKoan in PassingKoan"
   end
 end
diff --git a/test/display/progress_bar_test.exs b/test/display/progress_bar_test.exs
index 357ec94..e080ae1 100644
--- a/test/display/progress_bar_test.exs
+++ b/test/display/progress_bar_test.exs
@@ -13,7 +13,6 @@ defmodule ProgressBarTest do
     assert bar == "|=======>                      | 3 of 12"
   end
 
-
   test "full bar" do
     bar = ProgressBar.progress_bar(%{total: 12, current: 12})
     assert bar == "|=============================>| 12 of 12"
diff --git a/test/executor_test.exs b/test/executor_test.exs
index 394ff2f..d989123 100644
--- a/test/executor_test.exs
+++ b/test/executor_test.exs
@@ -12,6 +12,6 @@ defmodule ExecuteTest do
   end
 
   test "can access intro" do
-    assert SampleKoan.intro == "There is something\n"
+    assert SampleKoan.intro() == "There is something\n"
   end
 end
diff --git a/test/koans/agents_koans_test.exs b/test/koans/agents_koans_test.exs
index a1c2813..d0d70b5 100644
--- a/test/koans/agents_koans_test.exs
+++ b/test/koans/agents_koans_test.exs
@@ -8,7 +8,7 @@ defmodule AgentTests do
       "Why hello",
       "HI THERE",
       {:multiple, [["Milk"], ["Bread", "Milk"]]},
-      false,
+      false
     ]
 
     test_all(Agents, answers)
diff --git a/test/koans/enum_koans_test.exs b/test/koans/enum_koans_test.exs
index 4b3b428..cdfea9e 100644
--- a/test/koans/enum_koans_test.exs
+++ b/test/koans/enum_koans_test.exs
@@ -9,17 +9,17 @@ defmodule EnumTests do
       {:multiple, [true, false]},
       {:multiple, [true, false]},
       {:multiple, [true, false]},
-      [10,20,30],
-      [1,3],
+      [10, 20, 30],
+      [1, 3],
       [2],
-      [1,2,3],
-      [1,2,3,4,5],
-      [1,2,3],
+      [1, 2, 3],
+      [1, 2, 3, 4, 5],
+      [1, 2, 3],
       [a: 1, b: 2, c: 3],
       2,
       nil,
       :no_such_element,
-      6,
+      6
     ]
 
     test_all(Enums, answers)
diff --git a/test/koans/equalities_koan_test.exs b/test/koans/equalities_koan_test.exs
index 30f6a91..73897c0 100644
--- a/test/koans/equalities_koan_test.exs
+++ b/test/koans/equalities_koan_test.exs
@@ -10,7 +10,7 @@ defmodule EqualitiesTests do
       2,
       1,
       4,
-      2,
+      2
     ]
 
     test_all(Equalities, answers)
diff --git a/test/koans/functions_koans_test.exs b/test/koans/functions_koans_test.exs
index 20cb286..78b47d1 100644
--- a/test/koans/functions_koans_test.exs
+++ b/test/koans/functions_koans_test.exs
@@ -7,7 +7,7 @@ defmodule FunctionsTests do
       "Hello, World!",
       3,
       {:multiple, ["One and Two", "Only One"]},
-      {:multiple, ["Hello Hello Hello Hello Hello ","Hello Hello "]},
+      {:multiple, ["Hello Hello Hello Hello Hello ", "Hello Hello "]},
       {:multiple, [:entire_list, :single_thing]},
       {:multiple, ["10 is bigger than 5", "4 is not bigger than 27"]},
       {:multiple, ["The number was zero", "The number was 5"]},
@@ -18,7 +18,7 @@ defmodule FunctionsTests do
       100,
       1000,
       "Full Name",
-      {:multiple, ["GOOD", "good"]},
+      {:multiple, ["GOOD", "good"]}
     ]
 
     test_all(Functions, answers)
diff --git a/test/koans/genservers_koans_test.exs b/test/koans/genservers_koans_test.exs
index b8cae92..0b25b33 100644
--- a/test/koans/genservers_koans_test.exs
+++ b/test/koans/genservers_koans_test.exs
@@ -13,7 +13,7 @@ defmodule GenServersTests do
       {:error, "Incorrect password!"},
       "Congrats! Your process was successfully named.",
       {:ok, "Laptop unlocked!"},
-      {:multiple, ["Laptop unlocked!", "Incorrect password!", "Jack Sparrow"]},
+      {:multiple, ["Laptop unlocked!", "Incorrect password!", "Jack Sparrow"]}
     ]
 
     test_all(GenServers, answers)
diff --git a/test/koans/keyword_lists_koans_test.exs b/test/koans/keyword_lists_koans_test.exs
index dee5dc5..c3b28d7 100644
--- a/test/koans/keyword_lists_koans_test.exs
+++ b/test/koans/keyword_lists_koans_test.exs
@@ -8,7 +8,7 @@ defmodule KeywordListsTests do
       "bar",
       "baz",
       {:multiple, [:foo, "bar"]},
-      "foo",
+      "foo"
     ]
 
     test_all(KeywordLists, answers)
diff --git a/test/koans/lists_koans_test.exs b/test/koans/lists_koans_test.exs
index b9be677..2bbce26 100644
--- a/test/koans/lists_koans_test.exs
+++ b/test/koans/lists_koans_test.exs
@@ -3,24 +3,25 @@ defmodule ListsTests do
   import TestHarness
 
   test "Lists" do
-    answers = [1,
-               3,
-               [1, 2, :a, "b"],
-               [1,2],
-               [:a, :c],
-               [:a, :b],
-               ["life", "life", "life"],
-               [1, 2, 3, 4, 5],
-               [1, 4, 2, 3],
-               [10, 2, 3],
-               [1, 2, 3],
-               [1, 2, 3, 4],
-               [1, 2, 3, 4],
-               {1, 2, 3},
-               ["value"],
-               [],
-               ["value"],
-               ]
+    answers = [
+      1,
+      3,
+      [1, 2, :a, "b"],
+      [1, 2],
+      [:a, :c],
+      [:a, :b],
+      ["life", "life", "life"],
+      [1, 2, 3, 4, 5],
+      [1, 4, 2, 3],
+      [10, 2, 3],
+      [1, 2, 3],
+      [1, 2, 3, 4],
+      [1, 2, 3, 4],
+      {1, 2, 3},
+      ["value"],
+      [],
+      ["value"]
+    ]
 
     test_all(Lists, answers)
   end
diff --git a/test/koans/map_sets_koans_test.exs b/test/koans/map_sets_koans_test.exs
index 886fb41..043001d 100644
--- a/test/koans/map_sets_koans_test.exs
+++ b/test/koans/map_sets_koans_test.exs
@@ -14,7 +14,7 @@ defmodule MapSetsTest do
       false,
       true,
       7,
-      [1, 2, 3, 4, 5],
+      [1, 2, 3, 4, 5]
     ]
 
     test_all(MapSets, answers)
diff --git a/test/koans/maps_koans_test.exs b/test/koans/maps_koans_test.exs
index bc5385a..89603e7 100644
--- a/test/koans/maps_koans_test.exs
+++ b/test/koans/maps_koans_test.exs
@@ -13,7 +13,7 @@ defmodule MapsTests do
       false,
       %{:first_name => "Jon", :last_name => "Snow"},
       {:ok, "Baratheon"},
-      %{:first_name => "Jon", :last_name => "Snow"},
+      %{:first_name => "Jon", :last_name => "Snow"}
     ]
 
     test_all(Maps, answers)
diff --git a/test/koans/numbers_koans_test.exs b/test/koans/numbers_koans_test.exs
index 32660b5..a56b98a 100644
--- a/test/koans/numbers_koans_test.exs
+++ b/test/koans/numbers_koans_test.exs
@@ -30,7 +30,7 @@ defmodule NumbersTests do
       {:multiple, [6.0, 5.0, 8.9, -5.567]},
       {:multiple, [1, 10]},
       {:multiple, [true, true, false]},
-      {:multiple, [true, false]},
+      {:multiple, [true, false]}
     ]
 
     test_all(Numbers, answers)
diff --git a/test/koans/patterns_koans_test.exs b/test/koans/patterns_koans_test.exs
index 9a1f9ca..2d9fa36 100644
--- a/test/koans/patterns_koans_test.exs
+++ b/test/koans/patterns_koans_test.exs
@@ -5,14 +5,14 @@ defmodule PatternsTests do
   test "Pattern Matching" do
     answers = [
       1,
-      {:multiple, [1, [2,3,4]]},
-      [1,2,3,4],
+      {:multiple, [1, [2, 3, 4]]},
+      [1, 2, 3, 4],
       3,
       "eggs, milk",
       "Honda",
       MatchError,
       {:multiple, [:make, "Honda"]},
-      [1,2,3],
+      [1, 2, 3],
       {:multiple, ["Meow", "Woof", "Eh?"]},
       {:multiple, ["Mickey", "Donald", "I need a name!"]},
       "dog",
diff --git a/test/koans/processes_koans_test.exs b/test/koans/processes_koans_test.exs
index 2b50ac0..922b9ca 100644
--- a/test/koans/processes_koans_test.exs
+++ b/test/koans/processes_koans_test.exs
@@ -18,7 +18,7 @@ defmodule ProcessesTests do
       {:waited_too_long, "I am impatient"},
       {:exited, :random_reason},
       :normal,
-      :normal,
+      :normal
     ]
 
     test_all(Processes, answers)
diff --git a/test/koans/sigils_koans_test.exs b/test/koans/sigils_koans_test.exs
index 096fff2..be66732 100644
--- a/test/koans/sigils_koans_test.exs
+++ b/test/koans/sigils_koans_test.exs
@@ -11,7 +11,7 @@ defmodule SigilsTests do
       ~S(1 + 1 = #{1+1}),
       ["Hello", "world"],
       ["Hello", "123"],
-      ["Hello", ~S(#{1+1})],
+      ["Hello", ~S(#{1+1})]
     ]
 
     test_all(Sigils, answers)
diff --git a/test/koans/strings_koan_test.exs b/test/koans/strings_koan_test.exs
index 9287716..ee985f6 100644
--- a/test/koans/strings_koan_test.exs
+++ b/test/koans/strings_koan_test.exs
@@ -13,7 +13,7 @@ defmodule StringTests do
       "banana",
       "banana",
       "StringStringString",
-      "LISTEN",
+      "LISTEN"
     ]
 
     test_all(Strings, answers)
diff --git a/test/koans/structs_koans_test.exs b/test/koans/structs_koans_test.exs
index 596f79d..e3f45a4 100644
--- a/test/koans/structs_koans_test.exs
+++ b/test/koans/structs_koans_test.exs
@@ -11,7 +11,7 @@ defmodule StructsTests do
       {:ok, 22},
       %Structs.Airline{plane: %Structs.Plane{maker: :airbus}, name: "Southwest"},
       %Structs.Airline{plane: %Structs.Plane{maker: :boeing, passengers: 202}, name: "Southwest"},
-      %{plane: %{maker: :cessna}, name: "Southwest"},
+      %{plane: %{maker: :cessna}, name: "Southwest"}
     ]
 
     test_all(Structs, answers)
diff --git a/test/koans/tasks_koans_test.exs b/test/koans/tasks_koans_test.exs
index 2a70899..1a493fc 100644
--- a/test/koans/tasks_koans_test.exs
+++ b/test/koans/tasks_koans_test.exs
@@ -9,8 +9,8 @@ defmodule TasksTests do
       nil,
       false,
       9,
-      [1,4,9,16],
-      ]
+      [1, 4, 9, 16]
+    ]
 
     test_all(Tasks, answers)
   end
diff --git a/test/koans/tuples_koans_test.exs b/test/koans/tuples_koans_test.exs
index 0e584df..81fd73a 100644
--- a/test/koans/tuples_koans_test.exs
+++ b/test/koans/tuples_koans_test.exs
@@ -11,7 +11,7 @@ defmodule TupleTests do
       {:a, :new_thing, "hi"},
       {"Huey", "Dewey", "Louie"},
       {:this, :is, :awesome},
-      [:this, :can, :be, :a, :list],
+      [:this, :can, :be, :a, :list]
     ]
 
     test_all(Tuples, answers)
diff --git a/test/runner_test.exs b/test/runner_test.exs
index db09ca2..26314ff 100644
--- a/test/runner_test.exs
+++ b/test/runner_test.exs
@@ -5,5 +5,4 @@ defmodule RunnerTest do
     path = "lib/koans/01_just_an_example.ex"
     assert Runner.path_to_number(path) == 1
   end
-
 end
diff --git a/test/test_helper.exs b/test/test_helper.exs
index c302526..56d98f4 100644
--- a/test/test_helper.exs
+++ b/test/test_helper.exs
@@ -23,10 +23,10 @@ defmodule TestHarness do
   end
 
   defp check_results(results) do
-    Enum.each(results, &(assert &1 == :passed))
+    Enum.each(results, &assert(&1 == :passed))
   end
 
   def run_all(pairs, module) do
-    Enum.map(pairs, fn ({koan, answer}) -> Execute.run_koan(module, koan, [answer]) end)
+    Enum.map(pairs, fn {koan, answer} -> Execute.run_koan(module, koan, [answer]) end)
   end
 end
diff --git a/test/tracker_test.exs b/test/tracker_test.exs
index c758f76..a433fc0 100644
--- a/test/tracker_test.exs
+++ b/test/tracker_test.exs
@@ -5,24 +5,24 @@ defmodule TrackerTest do
 
   test "can start" do
     Tracker.set_total(@sample_modules)
-    assert Tracker.summarize == %{total: 2, current: 0, visited_modules: []}
+    assert Tracker.summarize() == %{total: 2, current: 0, visited_modules: []}
   end
 
   test "can be notified of completed koans" do
     Tracker.set_total(@sample_modules)
     Tracker.completed(SampleKoan, :"Hi there")
-    assert Tracker.summarize == %{total: 2, current: 1, visited_modules: [SampleKoan]}
+    assert Tracker.summarize() == %{total: 2, current: 1, visited_modules: [SampleKoan]}
   end
 
   test "multiple comletions of the same koan count only once" do
     Tracker.set_total(@sample_modules)
     Tracker.completed(SampleKoan, :"Hi there")
     Tracker.completed(SampleKoan, :"Hi there")
-    assert Tracker.summarize == %{total: 2, current: 1, visited_modules: [SampleKoan]}
+    assert Tracker.summarize() == %{total: 2, current: 1, visited_modules: [SampleKoan]}
   end
 
   test "knows when koans are not complete" do
     Tracker.set_total(@sample_modules)
-    refute Tracker.complete?
+    refute Tracker.complete?()
   end
 end