Slight refactoring and more test cases for SA1129 code fix

Author: nbarbettini

StyleCop.Analyzers/StyleCop.Analyzers.CodeFixes/ReadabilityRules/SA1129CodeFixProvider.cs

@@ -144,7 +144,7 @@ private static bool IsEnumWithDefaultMember(INamedTypeSymbol namedTypeSymbol, ou
                 return false;
             }
 
-            foundMemberName = foundMembers.Single().Name;
+            foundMemberName = foundMembers[0].Name;
             return true;
         }
 
@@ -155,10 +155,12 @@ private static bool IsEnumWithDefaultMember(INamedTypeSymbol namedTypeSymbol, ou
         /// <param name="memberName">The member name.</param>
         /// <returns>A new member access expression.</returns>
         private static SyntaxNode ConstructMemberAccessSyntax(TypeSyntax typeSyntax, string memberName)
-            => SyntaxFactory.MemberAccessExpression(
+        {
+            return SyntaxFactory.MemberAccessExpression(
                 SyntaxKind.SimpleMemberAccessExpression,
                 typeSyntax,
                 SyntaxFactory.IdentifierName(memberName));
+        }
 
         private class FixAll : DocumentBasedFixAllProvider
         {

StyleCop.Analyzers/StyleCop.Analyzers.Test/ReadabilityRules/SA1129UnitTests.cs

@@ -450,6 +450,7 @@ public class TestClass
         [InlineData("Member = 0")]
         [InlineData("Member = 0, Another = 1")]
         [InlineData("Another = 1, Member = 0")]
+        [InlineData("Member, Another")]
         public async Task VerifyEnumMemberReplacementBehaviorAsync(string declarationBody)
         {
             var testCode = $@"public class TestClass
@@ -491,6 +492,8 @@ private enum MyEnum {{ {declarationBody} }}
         [Theory]
         [InlineData("Member = 1")]
         [InlineData("Member = 1, Another = 2")]
+        [InlineData("FooMember = 0, BarMember = 0")]
+        [InlineData("FooMember, BarMember = 0")]
         public async Task VerifyEnumMemberDefaultBehaviorAsync(string declarationBody)
         {
             var testCode = $@"public class TestClass