Add matching of VSTest _Variant results.

Implements the VsTestScenarioOutlineExampleMatcher to detect _Variant style examples.
These occur when there are examples which contain characters that are illegal for method names,
or when examples contain duplicate values in the first column.

Fixes #507

src/Pickles/Pickles.TestFrameworks.UnitTests/StandardTestSuiteForScenarioOutlines.cs

@@ -19,6 +19,7 @@
 //  --------------------------------------------------------------------------------------------------------------------
 
 
+using System.Collections.Generic;
 using NFluent;
 
 
@@ -136,7 +137,30 @@ public void ThenCanReadExamplesWithRegexValuesFromScenarioOutline_ShouldBeTestRe
 
             var feature = new Feature { Name = "Scenarios With Special Characters" };
 
-            var scenarioOutline = new ScenarioOutline { Name = "This scenario contains examples with Regex-special characters", Feature = feature };
+            var scenarioOutline = new ScenarioOutline
+            {
+                Name = "This scenario contains examples with Regex-special characters",
+                Feature = feature,
+                Examples = new List<Example>
+                {
+                    new Example
+                    {
+                        TableArgument = new ExampleTable
+                        {
+                            DataRows = new List<TableRow>
+                            {
+                                new TableRow("**"),
+                                new TableRow("++"),
+                                new TableRow(".*"),
+                                new TableRow("[]"),
+                                new TableRow("{}"),
+                                new TableRow("()"),
+                                new TableRow(@"^.*(?<foo>BAR)\s[^0-9]{3,4}A+$"),
+                            }
+                        }
+                    }
+                }
+            };
 
             TestResult exampleResultOutline = results.GetScenarioOutlineResult(scenarioOutline);
             Check.That(exampleResultOutline).IsEqualTo(TestResult.Passed);

src/Pickles/Pickles.TestFrameworks.UnitTests/VsTest/WhenParsingVsTestResultsFileWithIndividualResults.cs

@@ -57,6 +57,12 @@ public WhenParsingVsTestResultsFileWithIndividualResults()
             base.ThenCanReadIndividualResultsFromScenarioOutline_MultipleExampleSections_ShouldBeTestResultFailed();
         }
 
+        [Test]
+        public new void ThenCanReadExamplesWithRegexValuesFromScenarioOutline_ShouldBeTestResultPassed()
+        {
+            base.ThenCanReadExamplesWithRegexValuesFromScenarioOutline_ShouldBeTestResultPassed();
+        }
+
         [Test]
         public new void ThenCanReadExamplesWithLongExampleValues()
         {

src/Pickles/Pickles.TestFrameworks/VsTest/VsTestScenarioOutlineExampleMatcher.cs

@@ -18,6 +18,8 @@
 //  </copyright>
 //  --------------------------------------------------------------------------------------------------------------------
 
+using System.Linq;
+using System.Text.RegularExpressions;
 using System.Xml.Linq;
 
 using PicklesDoc.Pickles.ObjectModel;
@@ -26,6 +28,9 @@ namespace PicklesDoc.Pickles.TestFrameworks.VsTest
 {
     public class VsTestScenarioOutlineExampleMatcher : IScenarioOutlineExampleMatcher
     {
+        private static readonly Regex VariantRegex = new Regex(@"(.*)_Variant([\d*])", RegexOptions.Compiled | RegexOptions.IgnoreCase);
+        private const int VariantNumberGroup = 2;
+
         public bool IsMatch(ScenarioOutline scenarioOutline, string[] exampleValues, object scenarioElement)
         {
             var element = (XElement)scenarioElement;
@@ -51,7 +56,23 @@ public bool IsMatch(ScenarioOutline scenarioOutline, string[] exampleValues, obj
                 .Replace('Ø', 'O')
                 .Replace('Å', 'A');
 
-      var isMatch = element.Name().ToUpperInvariant()
+            var variantMatch = VariantRegex.Match(element.Name().ToUpperInvariant());
+            if (variantMatch.Success)
+            {
+                int variantNumber;
+                if (int.TryParse(variantMatch.Groups[VariantNumberGroup].Value, out variantNumber))
+                {
+                    if (scenarioOutline.Examples?.Count > 0)
+                    {
+                        var allExamples = scenarioOutline.Examples.SelectMany(x => x.TableArgument.DataRows);
+                        var example = allExamples.ElementAt(variantNumber);
+
+                        return example.Cells.SequenceEqual(exampleValues);
+                    }
+                }
+            }
+
+            var isMatch = element.Name().ToUpperInvariant()
                 .EndsWith(matchValue);
 
             return isMatch;