Add beer-song generator

exercises/beer-song/BeerSong.cs

@@ -1,13 +1,13 @@
 using System;
 
-public static class Beer
+public static class BeerSong
 {
     public static string Verse(int number)
     {
         throw new NotImplementedException("You need to implement this function.");
     }
 
-    public static string Sing(int start, int stop)
+    public static string Verses(int begin, int end)
     {
         throw new NotImplementedException("You need to implement this function.");
     }

exercises/beer-song/Example.cs

@@ -1,6 +1,6 @@
 using System.Linq;
 
-public static class Beer
+public static class BeerSong
 {
     public static string Verse(int number)
     {
@@ -17,11 +17,6 @@ public static string Verse(int number)
         }
     }
 
-    public static string Sing(int start, int stop)
-    {
-        return Enumerable.Range(stop, start - stop + 1)
-                            .Reverse()
-                            .Select(Verse)
-                            .Aggregate("", (acc, verse) => acc + verse + "\n");
-    }
+    public static string Verses(int begin, int end)
+        => string.Join("\n", Enumerable.Range(end, begin - end + 1).Reverse().Select(Verse));
 }

generators/Data/CanonicalDataValue.cs

@@ -1,10 +1,24 @@
-using Newtonsoft.Json.Linq;
+using System;
+using System.Collections.Generic;
+using Newtonsoft.Json.Linq;
 
 namespace Generators.Data
 {
     public static class CanonicalDataValue
     {
-        public static string StringArrayToString(object expected)
-            => string.Join("\\n\"+\n\"", ((JArray) expected).Values<string>());
+        public static string ExpectedToMultiLineString(object expected)
+        {
+            switch (expected)
+            {
+                case IEnumerable<string> enumerable:
+                    return string.Join("\\n\"+\n\"", enumerable);
+                case JArray jarray:
+                    return ExpectedToMultiLineString(((JArray) expected).Values<string>());
+                case string str:
+                    return ExpectedToMultiLineString(str.Split('\n'));
+                default:
+                    throw new ArgumentException("Cannot convert expected value to multil-ine string.");
+            }
+        }
     }
 }

generators/Exercises/BeerSongExercise.cs

@@ -0,0 +1,33 @@
+using Generators.Data;
+using Generators.Methods;
+
+namespace Generators.Exercises
+{
+    public class BeerSongExercise : EqualityExercise
+    {
+        public BeerSongExercise() : base("beer-song")
+        {
+        }
+
+        protected override TestMethodData CreateTestMethodData(CanonicalData canonicalData, CanonicalDataCase canonicalDataCase, int index)
+        {
+            var testMethodData = base.CreateTestMethodData(canonicalData, canonicalDataCase, index);
+
+            testMethodData.Options.UseVariableForExpected = true;
+            testMethodData.Options.FormatExpected = true;
+
+            testMethodData.CanonicalDataCase.Expected = CanonicalDataValue.ExpectedToMultiLineString(testMethodData.CanonicalDataCase.Expected);
+
+            if (testMethodData.CanonicalDataCase.Property == "verse")
+                testMethodData.Options.InputProperty = "number";
+            else
+                testMethodData.CanonicalDataCase.Input = new[] 
+                { 
+                    testMethodData.CanonicalDataCase.Data["beginning"], 
+                    testMethodData.CanonicalDataCase.Data["end"]
+                };
+
+            return testMethodData;
+        }
+    }
+}

generators/Exercises/FoodChainExercise.cs

@@ -14,7 +14,7 @@ protected override TestMethodData CreateTestMethodData(CanonicalData canonicalDa
             var testMethodData = base.CreateTestMethodData(canonicalData, canonicalDataCase, index);
 
             testMethodData.Options.UseVariableForExpected = true;
-            testMethodData.CanonicalDataCase.Expected = CanonicalDataValue.StringArrayToString(canonicalDataCase.Expected);
+            testMethodData.CanonicalDataCase.Expected = CanonicalDataValue.ExpectedToMultiLineString(testMethodData.CanonicalDataCase.Expected);
 
             if (testMethodData.CanonicalDataCase.Data.ContainsKey("end verse"))
                 testMethodData.CanonicalDataCase.Input = new[] { testMethodData.CanonicalDataCase.Data["start verse"], testMethodData.CanonicalDataCase.Data["end verse"] };