Add support for "this" parameter (#5)

Sybil.UnitTests/MethodBuilderTests.cs

@@ -20,6 +20,7 @@ namespace Sybil.Tests
         private const string PublicEmptyMethod = "public string Test() => throw new NotImplementedException() ;";
         private const string PublicSealedEmptyMethod = "public sealed string Test() => throw new NotImplementedException() ;";
         private const string EmptyMethodWithParameter = "string Test(string someString) => throw new NotImplementedException() ;";
+        private const string EmptyMethodWithThisParameter = "string Test(this string someString) => throw new NotImplementedException() ;";
         private const string EmptyMethodWithParameterWithDefault = "string Test(string someString = null) => throw new NotImplementedException() ;";
         private const string MethodWithArrowExpression = "string Test() => this.someString ;";
         private const string PublicSealedMethodWithParameterAndExpression = "public sealed string Test(string someString = null) => this.someString ;";
@@ -131,6 +132,36 @@ namespace Sybil.Tests
             returnedBuilder.Should().NotBeNull().And.Subject.Should().Be(this.builder);
         }
 
+        [TestMethod]
+        public void WithThisParameter_ParameterNameNull_ThrowsArgumentNullException()
+        {
+            var action = () =>
+            {
+                this.builder.WithThisParameter(ParameterType, null);
+            };
+
+            action.Should().Throw<ArgumentNullException>();
+        }
+
+        [TestMethod]
+        public void WithThisParameter_ParameterTypeNull_ThrowsArgumentNullException()
+        {
+            var action = () =>
+            {
+                this.builder.WithThisParameter(null, ParameterName);
+            };
+
+            action.Should().Throw<ArgumentNullException>();
+        }
+
+        [TestMethod]
+        public void WithThisParameter_ParameterValid_ReturnsBuilder()
+        {
+            var returnedBuilder = this.builder.WithThisParameter(ParameterType, ParameterName);
+
+            returnedBuilder.Should().NotBeNull().And.Subject.Should().Be(this.builder);
+        }
+
         [TestMethod]
         public void WithBody_BodyNull_ThrowsArgumentNullException()
         {
@@ -209,6 +240,14 @@ namespace Sybil.Tests
             result.Should().Be(EmptyMethodWithParameterWithDefault);
         }
 
+        [TestMethod]
+        public void WithThisParameter_ReturnsExpectedString()
+        {
+            var result = this.builder.WithThisParameter(ParameterType, ParameterName).Build().ToFullString();
+
+            result.Should().Be(EmptyMethodWithThisParameter);
+        }
+
         [TestMethod]
         public void WithBody_ReturnsExpectedString()
         {

Sybil/MethodBuilder.cs

@@ -53,7 +53,7 @@ namespace Sybil
 
             var parameter = SyntaxFactory.Parameter(
                 SyntaxFactory.List<AttributeListSyntax>(),
-                new SyntaxTokenList(),
+                SyntaxFactory.TokenList(),
                 type: SyntaxFactory.ParseTypeName(parameterType),
                 identifier: SyntaxFactory.ParseToken(parameterName),
                 @default: equalsValueClauseSyntax);
@@ -62,6 +62,22 @@ namespace Sybil
 
             return this;
         }
+        public MethodBuilder WithThisParameter(string parameterType, string parameterName)
+        {
+            _ = string.IsNullOrWhiteSpace(parameterName) ? throw new ArgumentNullException(nameof(parameterName)) : parameterName;
+            _ = string.IsNullOrWhiteSpace(parameterType) ? throw new ArgumentNullException(nameof(parameterType)) : parameterType;
+
+            var parameter = SyntaxFactory.Parameter(
+                SyntaxFactory.List<AttributeListSyntax>(),
+                SyntaxFactory.TokenList(SyntaxFactory.Token(SyntaxKind.ThisKeyword)),
+                type: SyntaxFactory.ParseTypeName(parameterType),
+                identifier: SyntaxFactory.ParseToken(parameterName),
+                @default: null);
+
+            this.MethodDeclarationSyntax = this.MethodDeclarationSyntax.AddParameterListParameters(parameter);
+
+            return this;
+        }
         public MethodBuilder WithBody(string body)
         {
             this.BlockBody = SyntaxFactory.Block(

Sybil/Sybil.csproj

@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <TargetFramework>netstandard2.0</TargetFramework>
-    <Version>0.2.0</Version>
+    <Version>0.3.0</Version>
   </PropertyGroup>
 
   <PropertyGroup>