SA1517UnitTests.cs

// Copyright (c) Contributors to the New StyleCop Analyzers project.
// Licensed under the MIT License. See LICENSE in the project root for license information.

#nullable disable

namespace StyleCop.Analyzers.Test.LayoutRules
{
    using System.Threading;
    using System.Threading.Tasks;
    using Microsoft.CodeAnalysis.Testing;
    using StyleCop.Analyzers.LayoutRules;
    using Xunit;
    using static StyleCop.Analyzers.Test.Verifiers.StyleCopCodeFixVerifier<
        StyleCop.Analyzers.LayoutRules.SA1517CodeMustNotContainBlankLinesAtStartOfFile,
        StyleCop.Analyzers.LayoutRules.SA1517CodeFixProvider>;

    /// <summary>
    /// Unit tests for <see cref="SA1517CodeMustNotContainBlankLinesAtStartOfFile"/>.
    /// </summary>
    public class SA1517UnitTests
    {
        private const string BaseCode = @"using System.Diagnostics;
public class Foo
{
    public void Bar(int i)
    {
        Debug.Assert(true);
    }
}";

        /// <summary>
        /// Verifies that blank lines at the start of the file will produce a warning.
        /// </summary>
        /// <returns>A <see cref="Task"/> representing the asynchronous unit test.</returns>
        [Fact]
        public async Task TestWithBlankLinesAtStartOfFileAsync()
        {
            var testCode = "\r\n\r\n" + BaseCode;
            await VerifyCSharpDiagnosticAsync(testCode, this.GenerateExpectedWarning(1, 1), CancellationToken.None).ConfigureAwait(true);
        }

        /// <summary>
        /// Verifies that blank linefeed only lines at the start of the file will produce a warning.
        /// </summary>
        /// <returns>A <see cref="Task"/> representing the asynchronous unit test.</returns>
        [Fact]
        public async Task TestWithBlankLinefeedOnlyLinesAtStartOfFileAsync()
        {
            var testCode = "\n\n" + BaseCode;
            await VerifyCSharpDiagnosticAsync(testCode, this.GenerateExpectedWarning(1, 1), CancellationToken.None).ConfigureAwait(true);
        }

        /// <summary>
        /// Verifies that non-whitespace trivia will not produce a warning.
        /// </summary>
        /// <returns>A <see cref="Task"/> representing the asynchronous unit test.</returns>
        [Fact]
        public async Task TestWithNonWhitespaceTriviaAsync()
        {
            var testCode = "#if true\r\n" + BaseCode + "\r\n#endif\r\n";
            await VerifyCSharpDiagnosticAsync(testCode, DiagnosticResult.EmptyDiagnosticResults, CancellationToken.None).ConfigureAwait(true);
        }

        /// <summary>
        /// Verifies that blank lines followed by non-whitespace trivia will produce a warning.
        /// </summary>
        /// <returns>A <see cref="Task"/> representing the asynchronous unit test.</returns>
        [Fact]
        public async Task TestWithNonWhitespaceTriviaAndLeadingBlankLinesAsync()
        {
            var testCode = "\r\n\r\n#if true\r\n" + BaseCode + "\r\n#endif\r\n";
            await VerifyCSharpDiagnosticAsync(testCode, this.GenerateExpectedWarning(1, 1), CancellationToken.None).ConfigureAwait(true);
        }

        /// <summary>
        /// Verifies that no blank lines at the start of the file will not produce a warning.
        /// </summary>
        /// <returns>A <see cref="Task"/> representing the asynchronous unit test.</returns>
        [Fact]
        public async Task TestWithoutCarriageReturnLineFeedAtStartOfFileAsync()
        {
            await VerifyCSharpDiagnosticAsync(BaseCode, DiagnosticResult.EmptyDiagnosticResults, CancellationToken.None).ConfigureAwait(true);
        }

        /// <summary>
        /// Verifies that invalid spacing will not trigger SA1517.
        /// </summary>
        /// <returns>A <see cref="Task"/> representing the asynchronous unit test.</returns>
        [Fact]
        public async Task TestWithInvalidSpacingAsync()
        {
            var testCode = "    " + BaseCode;
            await VerifyCSharpDiagnosticAsync(testCode, DiagnosticResult.EmptyDiagnosticResults, CancellationToken.None).ConfigureAwait(true);
        }

        /// <summary>
        /// Verifies that the code fix provider will strip leading blank lines.
        /// </summary>
        /// <returns>A <see cref="Task"/> representing the asynchronous unit test.</returns>
        [Fact]
        public async Task TestCodeFixProviderStripsLeadingBlankLinesAsync()
        {
            var testCode = "\r\n\r\n" + BaseCode;
            var fixedTestCode = BaseCode;

            var expected = Diagnostic().WithLocation(1, 1);
            await VerifyCSharpFixAsync(testCode, expected, fixedTestCode, CancellationToken.None).ConfigureAwait(true);
        }

        /// <summary>
        /// Verifies that the code fix provider will not strip leading whitespace other than blank lines.
        /// </summary>
        /// <returns>A <see cref="Task"/> representing the asynchronous unit test.</returns>
        [Fact]
        public async Task TestCodeFixProviderHandlesWhitespaceProperlyAsync()
        {
            var testCode = "\r\n   " + BaseCode;
            var fixedTestCode = "   " + BaseCode;

            var expected = Diagnostic().WithLocation(1, 1);
            await VerifyCSharpFixAsync(testCode, expected, fixedTestCode, CancellationToken.None).ConfigureAwait(true);
        }

        /// <summary>
        /// Verifies that the code fix provider will strip whitespace on blank lines.
        /// </summary>
        /// <returns>A <see cref="Task"/> representing the asynchronous unit test.</returns>
        [Fact]
        public async Task TestCodeFixProviderHandlesBlankLinesWithWhitespaceProperlyAsync()
        {
            var testCode = "   \r\n   \r\n" + BaseCode;
            var fixedTestCode = BaseCode;

            var expected = Diagnostic().WithLocation(1, 1);
            await VerifyCSharpFixAsync(testCode, expected, fixedTestCode, CancellationToken.None).ConfigureAwait(true);
        }

        /// <summary>
        /// Verifies that the code fix provider will not strip non-whitespace trivia.
        /// </summary>
        /// <returns>A <see cref="Task"/> representing the asynchronous unit test.</returns>
        [Fact]
        public async Task TestCodeFixProviderHandlesNonWhitespaceTriviaProperlyAsync()
        {
            var testCode = "\r\n\r\n#if true\r\n" + BaseCode + "\r\n#endif\r\n";
            var fixedTestCode = "#if true\r\n" + BaseCode + "\r\n#endif\r\n";

            var expected = Diagnostic().WithLocation(1, 1);
            await VerifyCSharpFixAsync(testCode, expected, fixedTestCode, CancellationToken.None).ConfigureAwait(true);
        }

        private DiagnosticResult GenerateExpectedWarning(int line, int column)
        {
            return Diagnostic().WithLocation(line, column);
        }
    }
}