Sybil/Sybil.UnitTests/ConstructorBuilderTests.cs

using FluentAssertions;
using Microsoft.CodeAnalysis.CSharp.Syntax;
using Microsoft.VisualStudio.TestTools.UnitTesting;
using System;

namespace Sybil.Tests;

[TestClass]
public class ConstructorBuilderTests
{
    private const string Public = "public";
    private const string PublicSealed = "public sealed";
    private const string Null = "null";
    private const string ParameterType = "string";
    private const string ParameterName = "someString";
    private const string Name = "Test";
    private const string Body = "this.someString = someString;";
    private const string PublicEmptyConstructor =
@"public Test()
{
}";
    private const string PublicSealedEmptyConstructor =
@"public sealed Test()
{
}";
    private const string ConstructorWithParameter =
@"Test(string someString)
{
}";
    private const string ConstructorWithParameterWithDefault =
@"Test(string someString = null)
{
}";
    private const string ConstructorWithBody =
@"Test()
{
    this.someString = someString;
}";
    private const string ConstructorWithModifiersBodyAndParameter =
@"public public sealed Test(string someString = null)
{
    this.someString = someString;
}";

    private readonly ConstructorBuilder builder;

    public ConstructorBuilderTests()
    {
        this.builder = new ConstructorBuilder(Name);
    }

    [TestMethod]
    public void Constructor_NullName_ThrowArgumentNullException()
    {
        var action = () =>
        {
            _ = new ConstructorBuilder(null);
        };

        action.Should().Throw<ArgumentNullException>();
    }

    [TestMethod]
    public void WithModifier_ModifierNull_ThrowsArgumentNullException()
    {
        var action = () =>
        {
            this.builder.WithModifier(null);
        };

        action.Should().Throw<ArgumentNullException>();
    }

    [TestMethod]
    public void WithModifier_ModifierValid_ReturnsBuilder()
    {
        var returnedBuilder = this.builder.WithModifier(Public);

        returnedBuilder.Should().NotBeNull().And.Subject.Should().Be(this.builder);
    }

    [TestMethod]
    public void WithModifiers_ModifiersNull_ThrowsArgumentNullException()
    {
        var action = () =>
        {
            this.builder.WithModifiers(null);
        };

        action.Should().Throw<ArgumentNullException>();
    }

    [TestMethod]
    public void WithModifiers_ModifiersValid_ReturnsBuilder()
    {
        var returnedBuilder = this.builder.WithModifiers(PublicSealed);

        returnedBuilder.Should().NotBeNull().And.Subject.Should().Be(this.builder);
    }

    [TestMethod]
    public void WithBase_NullBase_ThrowsArgumentNullException()
    {
        var action = () =>
        {
            this.builder.WithBase(null);
        };

        action.Should().Throw<ArgumentNullException>();
    }

    [TestMethod]
    public void WithParameter_ParameterNameNull_ThrowsArgumentNullException()
    {
        var action = () =>
        {
            this.builder.WithParameter(ParameterType, null);
        };

        action.Should().Throw<ArgumentNullException>();
    }

    [TestMethod]
    public void WithParameter_ParameterTypeNull_ThrowsArgumentNullException()
    {
        var action = () =>
        {
            this.builder.WithParameter(null, ParameterName);
        };

        action.Should().Throw<ArgumentNullException>();
    }

    [TestMethod]
    public void WithParameter_ParameterValid_ReturnsBuilder()
    {
        var returnedBuilder = this.builder.WithParameter(ParameterType, ParameterName);

        returnedBuilder.Should().NotBeNull().And.Subject.Should().Be(this.builder);
    }

    [TestMethod]
    public void WithBody_BodyNull_ThrowsArgumentNullException()
    {
        var action = () =>
        {
            this.builder.WithBody(null);
        };

        action.Should().Throw<ArgumentNullException>();
    }

    [TestMethod]
    public void WithBody_BodyValid_ReturnsBuilder()
    {
        var returnedBuilder = this.builder.WithBody(Body);

        returnedBuilder.Should().NotBeNull().And.Subject.Should().Be(this.builder);
    }

    [TestMethod]
    public void Build_ReturnsConstructorDeclarationSyntax()
    {
        var syntax = this.builder.Build();

        syntax.Should().NotBeNull().And.Subject.Should().BeOfType<ConstructorDeclarationSyntax>();
    }

    [TestMethod]
    public void WithModifier_ReturnsExpectedString()
    {
        var result = this.builder.WithModifier(Public).Build().ToFullString();

        result.Should().Be(PublicEmptyConstructor);
    }

    [TestMethod]
    public void WithModifiers_ReturnsExpectedString()
    {
        var result = this.builder.WithModifiers(PublicSealed).Build().ToFullString();

        result.Should().Be(PublicSealedEmptyConstructor);
    }

    [TestMethod]
    public void WithParameter_ReturnsExpectedString()
    {
        var result = this.builder.WithParameter(ParameterType, ParameterName).Build().ToFullString();

        result.Should().Be(ConstructorWithParameter);
    }

    [TestMethod]
    public void WithParameter_WithDefault_ReturnsExpectedString()
    {
        var result = this.builder.WithParameter(ParameterType, ParameterName, Null).Build().ToFullString();

        result.Should().Be(ConstructorWithParameterWithDefault);
    }

    [TestMethod]
    public void WithBody_ReturnsExpectedString()
    {
        var result = this.builder.WithBody(Body).Build().ToFullString();

        result.Should().Be(ConstructorWithBody);
    }

    [TestMethod]
    public void WithBody_WithParameter_WithModifier_WithModifiers_ReturnsExpectedString()
    {
        var result = this.builder
            .WithBody(Body)
            .WithParameter(ParameterType, ParameterName, Null)
            .WithModifier(Public)
            .WithModifiers(PublicSealed)
            .Build()
            .ToFullString();

        result.Should().Be(ConstructorWithModifiersBodyAndParameter);
    }
}