Extract answers for the String module

lib/koans/04_strings.ex

@@ -2,38 +2,38 @@ defmodule Strings do
   use Koans
 
   koan "Strings are there to represent text" do
-    assert "hello" == "hello"
+    assert "hello" == :__
   end
 
   koan "They can be put together" do
-    assert "hello world" == "hello " <> "world"
+    assert "hello world" == :__ <> "world"
   end
 
   koan "Or pulled apart when needed" do
-    assert ["hello", "world"] == String.split("hello world")
+    assert :__ == String.split("hello world")
   end
 
   koan "Be careful, a message may be altered" do
-    assert "An awful day" == String.replace("An incredible day", "incredible", "awful")
+    assert :__ == String.replace("An incredible day", "incredible", "awful")
   end
 
   koan "But strings never lie about themselves" do
-    assert true == String.contains?("An incredible day", "incredible")
+    assert true == String.contains?("An incredible day", :__)
   end
 
   koan "Sometimes you want just the opposite of what is given" do
-    assert "banana" == String.reverse("ananab")
+    assert :__ == String.reverse("ananab")
   end
 
   koan "Other times a little cleaning is in order" do
-    assert "banana" == String.strip("  \n banana\n  ")
+    assert :__ == String.strip("  \n banana\n  ")
   end
 
   koan "Repetition is the mother of learning" do
-    assert "StringStringString" == String.duplicate("String", 3)
+    assert "StringStringString" == String.duplicate(:__, 3)
   end
 
   koan "Strings can be louder when necessary" do
-    assert "LISTEN" == String.upcase("listen")
+    assert "LISTEN" == String.upcase(:__)
   end
 end

test/koans_harness_test.exs

@@ -55,6 +55,22 @@ defmodule KoansHarnessTest do
     test_all(Maps, answers)
   end
 
+  test "String" do
+    answers = [
+      "hello",
+      "hello ",
+      ["hello", "world"],
+      "An awful day",
+      "incredible",
+      "banana",
+      "banana",
+      "String",
+      "listen"
+    ]
+
+    test_all(Strings, answers)
+  end
+
   def test_all(module, answers) do
     module.all_koans
     |> Enum.zip(answers)