Add special case for text variation making no change

Now when the textvariation is given an empty block, a vary sequence with no elements, correctly return that there is no variation found.

closes #963

# Conflicts:
#	Assets/Fungus/Docs/CHANGELOG.txt

Assets/Fungus/Docs/CHANGELOG.txt

@@ -12,6 +12,7 @@ Unreleased
 ## Changed
  - Block will LogError when an exception is caught from a Command being Executed.
  - WriterAudio.GetSecondsRemaining reports 0 if not playing. Thanks to KVinS.
+ - Add special case that skips variation logic for sequences that contains no elements, making no change.
 
 v3.13.6
 ======

Assets/Fungus/Scripts/Utils/TextVariationHandler.cs

@@ -168,6 +168,15 @@ namespace Fungus
                 }
             }
 
+            // As per issue #963 this should just return as if no variation 
+            if(varyingSections.Count == 1)
+            {
+                if (varyingSections[0].type == Section.VaryType.Sequence &&
+                    varyingSections[0].elements.Count == 0)
+                    return false;
+            }
+
+
             return varyingSections.Count > 0;
         }
 

Assets/Tests/Editor/FungusTextVariationSelectionTests.cs

@@ -114,5 +114,20 @@ namespace Fungus.Tests
                 Assert.Fail();
             }
         }
+
+        [Test]
+        public void SquareBracketsWithoutTypeNoImpact()
+        {
+            Fungus.TextVariationHandler.ClearHistory();
+
+            string startingText = @"This is test a [of changing nothing]";
+            const string expected = @"This is test a [of changing nothing]";
+
+            string res = string.Empty;
+
+            res = Fungus.TextVariationHandler.SelectVariations(startingText);
+
+            Assert.AreEqual(expected, res);
+        }
     }
 }