feat: Implement spam protection with configurable limits and auto-mute escalation

2026-09-05 23:34:09 +02:00 · 2026-07-17 19:47:57 +02:00
parent 3281064720
commit 53d0d326cb
9 changed files with 556 additions and 0 deletions
@@ -0,0 +1,231 @@
+using EchoHub.Core.Models;
+using EchoHub.Server.Config;
+using EchoHub.Server.Services;
+using Xunit;
+
+namespace EchoHub.Tests;
+
+public class SpamGuardTests
+{
+    private static readonly DateTimeOffset T0 = new(2026, 1, 1, 12, 0, 0, TimeSpan.Zero);
+    private static readonly Guid Alice = Guid.NewGuid();
+
+    private static SpamGuard CreateGuard(Action<SpamOptions>? configure = null)
+    {
+        var options = new SpamOptions();
+        configure?.Invoke(options);
+        return new SpamGuard(options);
+    }
+
+    // ── Message flood ─────────────────────────────────────────────────
+
+    [Fact]
+    public void Flood_UnderLimit_Allowed()
+    {
+        var guard = CreateGuard();
+
+        for (var i = 0; i < 8; i++)
+        {
+            var verdict = guard.CheckMessage(Alice, ServerRole.Member, $"msg {i}", T0.AddMilliseconds(i * 100));
+            Assert.Equal(SpamVerdictKind.Allowed, verdict.Kind);
+        }
+    }
+
+    [Fact]
+    public void Flood_OverLimit_Rejected()
+    {
+        var guard = CreateGuard();
+
+        for (var i = 0; i < 8; i++)
+            guard.CheckMessage(Alice, ServerRole.Member, $"msg {i}", T0.AddMilliseconds(i * 100));
+
+        var verdict = guard.CheckMessage(Alice, ServerRole.Member, "msg 9", T0.AddSeconds(1));
+
+        Assert.Equal(SpamVerdictKind.Rejected, verdict.Kind);
+        Assert.Contains("too fast", verdict.Reason);
+    }
+
+    [Fact]
+    public void Flood_RecoversAfterWindow()
+    {
+        var guard = CreateGuard();
+
+        for (var i = 0; i < 9; i++)
+            guard.CheckMessage(Alice, ServerRole.Member, $"msg {i}", T0.AddMilliseconds(i * 100));
+
+        // The whole window has passed with no attempts — allowed again
+        var verdict = guard.CheckMessage(Alice, ServerRole.Member, "later", T0.AddSeconds(10));
+
+        Assert.Equal(SpamVerdictKind.Allowed, verdict.Kind);
+    }
+
+    [Fact]
+    public void Flood_IsPerUser()
+    {
+        var guard = CreateGuard();
+        var bob = Guid.NewGuid();
+
+        for (var i = 0; i < 9; i++)
+            guard.CheckMessage(Alice, ServerRole.Member, $"msg {i}", T0.AddMilliseconds(i * 100));
+
+        var verdict = guard.CheckMessage(bob, ServerRole.Member, "hello", T0.AddSeconds(1));
+
+        Assert.Equal(SpamVerdictKind.Allowed, verdict.Kind);
+    }
+
+    // ── Duplicates ────────────────────────────────────────────────────
+
+    [Fact]
+    public void Duplicates_UpToLimit_Allowed_ThenRejected()
+    {
+        // Slow enough that the flood window never trips (one message per 10 s)
+        var guard = CreateGuard();
+
+        for (var i = 0; i < 3; i++)
+        {
+            var v = guard.CheckMessage(Alice, ServerRole.Member, "same thing", T0.AddSeconds(i * 10));
+            Assert.Equal(SpamVerdictKind.Allowed, v.Kind);
+        }
+
+        var verdict = guard.CheckMessage(Alice, ServerRole.Member, "same thing", T0.AddSeconds(30));
+
+        Assert.Equal(SpamVerdictKind.Rejected, verdict.Kind);
+        Assert.Contains("Duplicate", verdict.Reason);
+    }
+
+    [Fact]
+    public void Duplicates_CaseAndWhitespaceInsensitive()
+    {
+        var guard = CreateGuard(o => o.MaxDuplicateMessages = 1);
+
+        guard.CheckMessage(Alice, ServerRole.Member, "Hello World", T0);
+        var verdict = guard.CheckMessage(Alice, ServerRole.Member, "  hello world  ", T0.AddSeconds(10));
+
+        Assert.Equal(SpamVerdictKind.Rejected, verdict.Kind);
+    }
+
+    [Fact]
+    public void Duplicates_ResetByDifferentMessage()
+    {
+        var guard = CreateGuard(o => o.MaxDuplicateMessages = 1);
+
+        guard.CheckMessage(Alice, ServerRole.Member, "same", T0);
+        guard.CheckMessage(Alice, ServerRole.Member, "different", T0.AddSeconds(10));
+        var verdict = guard.CheckMessage(Alice, ServerRole.Member, "same", T0.AddSeconds(20));
+
+        Assert.Equal(SpamVerdictKind.Allowed, verdict.Kind);
+    }
+
+    // ── Escalation → auto-mute ────────────────────────────────────────
+
+    [Fact]
+    public void Escalation_EnoughViolations_ReturnsAutoMute()
+    {
+        var guard = CreateGuard(o => o.ViolationThreshold = 3);
+        SpamVerdict verdict = default;
+
+        // Keep hammering inside the flood window: 8 allowed, then rejections accumulate
+        for (var i = 0; i < 8 + 3; i++)
+            verdict = guard.CheckMessage(Alice, ServerRole.Member, $"m{i}", T0.AddMilliseconds(i * 50));
+
+        Assert.Equal(SpamVerdictKind.AutoMute, verdict.Kind);
+        Assert.Equal(TimeSpan.FromMinutes(5), verdict.MuteDuration);
+    }
+
+    [Fact]
+    public void Escalation_ClearsViolations_NextRejectionIsPlain()
+    {
+        var guard = CreateGuard(o => o.ViolationThreshold = 3);
+
+        for (var i = 0; i < 8 + 3; i++)
+            guard.CheckMessage(Alice, ServerRole.Member, $"m{i}", T0.AddMilliseconds(i * 50));
+
+        // Still inside the flood window — rejected, but the counter restarted
+        var verdict = guard.CheckMessage(Alice, ServerRole.Member, "again", T0.AddSeconds(2));
+
+        Assert.Equal(SpamVerdictKind.Rejected, verdict.Kind);
+    }
+
+    [Fact]
+    public void Escalation_AutoMuteDisabled_StaysRejected()
+    {
+        var guard = CreateGuard(o => { o.ViolationThreshold = 3; o.AutoMuteMinutes = 0; });
+        SpamVerdict verdict = default;
+
+        for (var i = 0; i < 8 + 10; i++)
+            verdict = guard.CheckMessage(Alice, ServerRole.Member, $"m{i}", T0.AddMilliseconds(i * 50));
+
+        Assert.Equal(SpamVerdictKind.Rejected, verdict.Kind);
+    }
+
+    // ── Exemptions / master switch ────────────────────────────────────
+
+    [Theory]
+    [InlineData(ServerRole.Mod)]
+    [InlineData(ServerRole.Admin)]
+    [InlineData(ServerRole.Owner)]
+    public void ModAndAbove_AlwaysAllowed(ServerRole role)
+    {
+        var guard = CreateGuard();
+
+        for (var i = 0; i < 50; i++)
+        {
+            var verdict = guard.CheckMessage(Alice, role, "same spam", T0.AddMilliseconds(i * 10));
+            Assert.Equal(SpamVerdictKind.Allowed, verdict.Kind);
+        }
+    }
+
+    [Fact]
+    public void Disabled_EverythingAllowed()
+    {
+        var guard = CreateGuard(o => o.Enabled = false);
+
+        for (var i = 0; i < 50; i++)
+            Assert.Equal(SpamVerdictKind.Allowed,
+                guard.CheckMessage(Alice, ServerRole.Member, "same", T0.AddMilliseconds(i * 10)).Kind);
+
+        Assert.Equal(SpamVerdictKind.Allowed, guard.CheckJoin(Alice, ServerRole.Member, T0).Kind);
+        Assert.Equal(SpamVerdictKind.Allowed, guard.CheckChannelCreate(Alice, ServerRole.Member, T0).Kind);
+        Assert.False(guard.Enabled);
+    }
+
+    // ── Join throttle ─────────────────────────────────────────────────
+
+    [Fact]
+    public void Joins_OverLimit_Rejected_ThenRecovers()
+    {
+        var guard = CreateGuard(o => { o.MaxJoinsPerWindow = 5; o.JoinWindowSeconds = 30; });
+
+        for (var i = 0; i < 5; i++)
+            Assert.Equal(SpamVerdictKind.Allowed, guard.CheckJoin(Alice, ServerRole.Member, T0.AddSeconds(i)).Kind);
+
+        Assert.Equal(SpamVerdictKind.Rejected, guard.CheckJoin(Alice, ServerRole.Member, T0.AddSeconds(6)).Kind);
+        Assert.Equal(SpamVerdictKind.Allowed, guard.CheckJoin(Alice, ServerRole.Member, T0.AddSeconds(60)).Kind);
+    }
+
+    // ── Channel-create throttle ───────────────────────────────────────
+
+    [Fact]
+    public void ChannelCreates_OverLimit_Rejected_ThenRecovers()
+    {
+        var guard = CreateGuard();
+
+        for (var i = 0; i < 3; i++)
+            Assert.Equal(SpamVerdictKind.Allowed, guard.CheckChannelCreate(Alice, ServerRole.Member, T0.AddSeconds(i)).Kind);
+
+        Assert.Equal(SpamVerdictKind.Rejected, guard.CheckChannelCreate(Alice, ServerRole.Member, T0.AddSeconds(10)).Kind);
+        Assert.Equal(SpamVerdictKind.Allowed, guard.CheckChannelCreate(Alice, ServerRole.Member, T0.AddMinutes(15)).Kind);
+    }
+
+    [Fact]
+    public void JoinAndCreateRejections_NeverAutoMute()
+    {
+        var guard = CreateGuard(o => { o.MaxJoinsPerWindow = 1; o.ViolationThreshold = 2; });
+
+        for (var i = 0; i < 20; i++)
+        {
+            var verdict = guard.CheckJoin(Alice, ServerRole.Member, T0.AddSeconds(i));
+            Assert.NotEqual(SpamVerdictKind.AutoMute, verdict.Kind);
+        }
+    }
+}