RR0078JoinStringExpressionsTests.cs

// Copyright (c) .NET Foundation and Contributors. Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.

using System;
using System.Threading.Tasks;
using Roslynator.Testing.CSharp;
using Xunit;

namespace Roslynator.CSharp.Refactorings.Tests;

public class RR0078JoinStringExpressionsTests : AbstractCSharpRefactoringVerifier
{
    public override string RefactoringId { get; } = RefactoringIdentifiers.JoinStringExpressions;

    [Fact, Trait(Traits.Refactoring, RefactoringIdentifiers.JoinStringExpressions)]
    public async Task Test()
    {
        await VerifyRefactoringAsync("""
class C
{
    void M(string s)
    {
        s = s + [|"a" + @"b"|];
    }
}
""", """
class C
{
    void M(string s)
    {
        s = s + "ab";
    }
}
""", equivalenceKey: EquivalenceKey.Create(RefactoringId));
    }

    [Fact, Trait(Traits.Refactoring, RefactoringIdentifiers.JoinStringExpressions)]
    public async Task Test_ToInterpolatedString()
    {
        await VerifyRefactoringAsync("""
class C
{
    void M(string s1, string s2, string s3)
    {
        s1 = [|s1 + "a" + s2 +  @"b" + s3|];
    }
}
""", """
class C
{
    void M(string s1, string s2, string s3)
    {
        s1 = $"{s1}a{s2}b{s3}";
    }
}
""", equivalenceKey: EquivalenceKey.Create(RefactoringId));
    }

    [Fact, Trait(Traits.Refactoring, RefactoringIdentifiers.JoinStringExpressions)]
    public async Task Test_RegularAndInterpolated()
    {
        await VerifyRefactoringAsync("""
class C
{
    void M()
    {
        string s = null;
        s = [|"{}" + $"{s}"|];
    }
}
""", """
class C
{
    void M()
    {
        string s = null;
        s = $"{{}}{s}";
    }
}
""", equivalenceKey: EquivalenceKey.Create(RefactoringId));
    }

    [Fact, Trait(Traits.Refactoring, RefactoringIdentifiers.JoinStringExpressions)]
    public async Task Test_VerbatimAndInterpolated()
    {
        await VerifyRefactoringAsync("""
class C
{
    void M()
    {
        string s = null;
        s = [|@" "" {} " + $" \" {s} "|];
    }
}
""", """
class C
{
    void M()
    {
        string s = null;
        s = $" \" {{}}  \" {s} ";
    }
}
""", equivalenceKey: EquivalenceKey.Create(RefactoringId));
    }

    [Fact, Trait(Traits.Refactoring, RefactoringIdentifiers.JoinStringExpressions)]
    public async Task Test_RegularAndVerbatimInterpolated()
    {
        await VerifyRefactoringAsync("""
class C
{
    void M()
    {
        string s = null;
        s = [|" \" {} " + $@" "" {s} "|];
    }
}
""", """
class C
{
    void M()
    {
        string s = null;
        s = $" \" {{}}  \" {s} ";
    }
}
""", equivalenceKey: EquivalenceKey.Create(RefactoringId));
    }

    [Fact, Trait(Traits.Refactoring, RefactoringIdentifiers.JoinStringExpressions)]
    public async Task Test_RegularAndMultilineVerbatim()
    {
        string newLineText = (Environment.NewLine == "\r\n") ? @"\r\n" : @"\n";

        await VerifyRefactoringAsync("""
class C
{
    void M()
    {
        string s = null;
        s = [|" \r\n " + @"
"|];
    }
}
""", $$"""
class C
{
    void M()
    {
        string s = null;
        s = " \r\n {{newLineText}}";
    }
}
""", equivalenceKey: EquivalenceKey.Create(RefactoringId));
    }

    [Fact, Trait(Traits.Refactoring, RefactoringIdentifiers.JoinStringExpressions)]
    public async Task Test_ToMultilineStringLiteral()
    {
        await VerifyRefactoringAsync("""
class C
{
    void M()
    {
        string s = null;
        s = [|"\r\n" +
" "|];
    }
}
""", """
class C
{
    void M()
    {
        string s = null;
        s = @"
 ";
    }
}
""", equivalenceKey: EquivalenceKey.Create(RefactoringId, "Multiline"));
    }

    [Fact, Trait(Traits.Refactoring, RefactoringIdentifiers.JoinStringExpressions)]
    public async Task Test_StringConcatenationOnMultipleLines_LeadingTriviaIncluded()
    {
        await VerifyRefactoringAsync("""
class C
{
    void M()
    {
        string s =
[|            "a" +
            "b" +
            "c"|];
    }
}
""", """
class C
{
    void M()
    {
        string s =
            "abc";
    }
}
""", equivalenceKey: EquivalenceKey.Create(RefactoringId));
    }

    [Fact, Trait(Traits.Refactoring, RefactoringIdentifiers.JoinStringExpressions)]
    public async Task Test_StringConcatenationOnMultipleLines_TrailingTriviaIncluded()
    {
        await VerifyRefactoringAsync("""
class C
{
    void M()
    {
        string s =
            [|"a" +
            "b" +
            "c" //|]
;
    }
}
""", """
class C
{
    void M()
    {
        string s =
            "abc" //
;
    }
}
""", equivalenceKey: EquivalenceKey.Create(RefactoringId));
    }

    [Fact, Trait(Traits.Refactoring, RefactoringIdentifiers.JoinStringExpressions)]
    public async Task Test_StringConcatenation_PreprocessorDirectives()
    {
        await VerifyRefactoringAsync("""
class C
{
    void M()
    {
        string s = "a"
#if DEBUG
            + [|"b" + "c"|];
    }
#endif
}
""", """
class C
{
    void M()
    {
        string s = "a"
#if DEBUG
            + "bc";
    }
#endif
}
""", equivalenceKey: EquivalenceKey.Create(RefactoringId), options: Options.WithDebugPreprocessorSymbol());
    }
}