// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
using System;
using Microsoft.Extensions.Compliance.Classification;
using Xunit;
 
namespace Microsoft.Extensions.Compliance.Redaction.Test;
 
public static class NullRedactorTest
{
    [Fact]
    public static void NullRedactor_When_Given_Empty_String_Returns_Empty_String()
    {
        var r = NullRedactor.Instance;
 
        var emptyStringRedacted = r.Redact(string.Empty);
        Assert.Equal(string.Empty, emptyStringRedacted);
 
        string? s = null;
        emptyStringRedacted = r.Redact(s);
        Assert.Equal(string.Empty, emptyStringRedacted);
    }
 
    [Fact]
    public static void NullRedactor_When_Given_Empty_Buffer_Returns_0_Chars_Written()
    {
        var r = NullRedactor.Instance;
 
        Span<char> input = stackalloc char[0];
 
        var c = new char[1];
 
        var charsWritten = r.Redact(input, c);
 
        Assert.Equal(0, charsWritten);
        Assert.Equal('\0', c[0]);
    }
 
    [Fact]
    public static void NullRedactor_Handles_BufferTooSmall()
    {
        var r = NullRedactor.Instance;
        Assert.Throws<ArgumentException>(() => r.Redact("ABCD".AsSpan(), new char[1].AsSpan()));
    }
 
    [Fact]
    public static void NullRedactorProvider_Returns_Always_NullRedactor()
    {
        var dc1 = new DataClassification("TAX", "1");
        var dc2 = new DataClassification("TAX", "2");
        var dc3 = new DataClassification("TAX", "4");
 
        var rp = NullRedactorProvider.Instance;
        var redactor1 = NullRedactor.Instance;
        var redactor2 = rp.GetRedactor(dc1);
        var redactor3 = rp.GetRedactor(dc2);
        var redactor4 = rp.GetRedactor(dc3);
 
        Assert.Equal(redactor1, redactor2);
        Assert.Equal(redactor1, redactor3);
        Assert.Equal(redactor1, redactor4);
        Assert.IsAssignableFrom<NullRedactor>(redactor1);
    }
}