ScadaBridge/tests/ZB.MOM.WW.ScadaBridge.AuditLog.Tests/Redaction/SafeDefaultAuditRedactorTests.cs

using ZB.MOM.WW.Audit;
using ZB.MOM.WW.ScadaBridge.AuditLog.Redaction;
using ZB.MOM.WW.ScadaBridge.Commons.Types.Audit;

namespace ZB.MOM.WW.ScadaBridge.AuditLog.Tests.Redaction;

/// <summary>
/// Tests for
/// <see cref="SafeDefaultAuditRedactor"/> — the minimal always-safe
/// <see cref="ZB.MOM.WW.Audit.IAuditRedactor"/> fallback.
/// Header-only scrub of the always-sensitive default headers inside
/// <c>DetailsJson</c>'s RequestSummary / ResponseSummary; never throws, never
/// performs body / SQL / truncation work.
/// </summary>
public class SafeDefaultAuditRedactorTests
{
    private static AuditEvent EventWith(string? request = null, string? response = null)
    {
        var details = new AuditDetails
        {
            RequestSummary = request,
            ResponseSummary = response,
        };
        return new AuditEvent
        {
            EventId = Guid.NewGuid(),
            OccurredAtUtc = DateTimeOffset.UtcNow,
            Actor = "tester",
            Action = "ApiOutbound.ApiCall",
            Outcome = AuditOutcome.Success,
            DetailsJson = AuditDetailsCodec.Serialize(details),
        };
    }

    private static AuditDetails Details(AuditEvent evt) =>
        AuditDetailsCodec.Deserialize(evt.DetailsJson);

    /// <summary>Verifies that the default sensitive headers are redacted in the request summary.</summary>
    [Fact]
    public void Redacts_DefaultSensitiveHeaders_InRequestSummary()
    {
        var evt = EventWith(request: "Authorization: Bearer secret-token\nContent-Type: application/json");

        var result = SafeDefaultAuditRedactor.Instance.Apply(evt);

        var d = Details(result);
        Assert.Contains("Authorization: <redacted>", d.RequestSummary!);
        Assert.DoesNotContain("secret-token", d.RequestSummary!);
        Assert.Contains("Content-Type: application/json", d.RequestSummary!);
    }

    /// <summary>Verifies that the default sensitive headers are redacted in the response summary.</summary>
    [Fact]
    public void Redacts_DefaultSensitiveHeaders_InResponseSummary()
    {
        var evt = EventWith(response: "Set-Cookie: sessionid=abc123\nX-Other: ok");

        var result = SafeDefaultAuditRedactor.Instance.Apply(evt);

        var d = Details(result);
        Assert.Contains("Set-Cookie: <redacted>", d.ResponseSummary!);
        Assert.DoesNotContain("abc123", d.ResponseSummary!);
        Assert.Contains("X-Other: ok", d.ResponseSummary!);
    }

    /// <summary>Verifies that header names are matched case-insensitively when redacting.</summary>
    [Fact]
    public void CaseInsensitive_HeaderName_Redacted()
    {
        var evt = EventWith(request: "authorization: Bearer x-y-z");

        var result = SafeDefaultAuditRedactor.Instance.Apply(evt);

        Assert.Contains("<redacted>", Details(result).RequestSummary!);
        Assert.DoesNotContain("x-y-z", Details(result).RequestSummary!);
    }

    /// <summary>Verifies that a non-sensitive header is preserved unchanged.</summary>
    [Fact]
    public void NonSensitiveHeader_Preserved()
    {
        var evt = EventWith(request: "X-Request-Id: abc-123\nAccept: application/json");

        var result = SafeDefaultAuditRedactor.Instance.Apply(evt);

        var d = Details(result);
        Assert.Contains("X-Request-Id: abc-123", d.RequestSummary!);
        Assert.Contains("Accept: application/json", d.RequestSummary!);
    }

    /// <summary>Verifies that an event with null details takes the fast path and returns the same instance.</summary>
    [Fact]
    public void NullDetails_FastPath_ReturnsSameInstance()
    {
        var evt = new AuditEvent
        {
            EventId = Guid.NewGuid(),
            OccurredAtUtc = DateTimeOffset.UtcNow,
            Actor = "tester",
            Action = "ApiOutbound.ApiCall",
            Outcome = AuditOutcome.Success,
            DetailsJson = null,
        };

        var result = SafeDefaultAuditRedactor.Instance.Apply(evt);

        Assert.Same(evt, result);
    }

    /// <summary>Verifies that malformed details JSON never causes the redactor to throw.</summary>
    [Fact]
    public void MalformedDetailsJson_NeverThrows()
    {
        var evt = new AuditEvent
        {
            EventId = Guid.NewGuid(),
            OccurredAtUtc = DateTimeOffset.UtcNow,
            Actor = "tester",
            Action = "ApiOutbound.ApiCall",
            Outcome = AuditOutcome.Success,
            DetailsJson = "{not valid json]",
        };

        var ex = Record.Exception(() => SafeDefaultAuditRedactor.Instance.Apply(evt));

        Assert.Null(ex);
    }
}