Add src files

tests/LibNftables.Tests/NftContextTests.cs

@@ -0,0 +1,142 @@
+using System.Globalization;
+
+namespace LibNftables.Tests;
+
+public sealed class NftContextTests
+{
+    [Fact]
+    public void ContextFlagsRoundTrip_Works()
+    {
+        if (!TryCreateContext(out var ctx))
+        {
+            return;
+        }
+
+        using (ctx)
+        {
+            ctx.DryRun = true;
+            Assert.True(ctx.DryRun);
+
+            ctx.OptimizeFlags = NftOptimizeFlags.Enabled;
+            Assert.True(ctx.OptimizeFlags.HasFlag(NftOptimizeFlags.Enabled));
+
+            ctx.InputFlags = NftInputFlags.NoDns | NftInputFlags.Json;
+            Assert.True(ctx.InputFlags.HasFlag(NftInputFlags.NoDns));
+            Assert.True(ctx.InputFlags.HasFlag(NftInputFlags.Json));
+
+            ctx.OutputFlags = NftOutputFlags.Json | NftOutputFlags.Echo | NftOutputFlags.Terse;
+            Assert.True(ctx.OutputFlags.HasFlag(NftOutputFlags.Json));
+            Assert.True(ctx.OutputFlags.HasFlag(NftOutputFlags.Echo));
+            Assert.True(ctx.OutputFlags.HasFlag(NftOutputFlags.Terse));
+
+            ctx.DebugFlags = NftDebugLevel.Parser | NftDebugLevel.Scanner;
+            Assert.True(ctx.DebugFlags.HasFlag(NftDebugLevel.Parser));
+            Assert.True(ctx.DebugFlags.HasFlag(NftDebugLevel.Scanner));
+        }
+    }
+
+    [Fact]
+    public void InvalidCommand_ThrowsNftExceptionWithErrorBuffer()
+    {
+        if (!TryCreateContext(out var ctx))
+        {
+            return;
+        }
+
+        using (ctx)
+        {
+            ctx.DryRun = true;
+            ctx.BufferError();
+
+            var ex = Assert.ThrowsAny<NftException>(() => ctx.RunCommand("this is not valid nft syntax"));
+            Assert.NotEqual(0, ex.NativeErrorCode);
+            Assert.False(string.IsNullOrWhiteSpace(ex.NativeErrorOutput));
+        }
+    }
+
+    [Fact]
+    public void ValidDryRunCommand_CanExecuteAndBufferOutput()
+    {
+        if (!TryCreateContext(out var ctx))
+        {
+            return;
+        }
+
+        if (!HasCapNetAdmin())
+        {
+            return;
+        }
+
+        using (ctx)
+        {
+            ctx.DryRun = true;
+            ctx.BufferOutput();
+            ctx.BufferError();
+
+            ctx.RunCommand("add table inet swig_test");
+            var output = ctx.GetOutputBuffer();
+            var error = ctx.GetErrorBuffer();
+
+            Assert.NotNull(output);
+            Assert.True(string.IsNullOrEmpty(error), $"Unexpected error buffer: {error}");
+        }
+    }
+
+    private static bool HasCapNetAdmin()
+    {
+        const int capNetAdminBit = 12;
+        const ulong mask = 1UL << capNetAdminBit;
+
+        try
+        {
+            foreach (var line in File.ReadLines("/proc/self/status"))
+            {
+                if (!line.StartsWith("CapEff:", StringComparison.Ordinal))
+                {
+                    continue;
+                }
+
+                var hex = line["CapEff:".Length..].Trim();
+                if (ulong.TryParse(hex, NumberStyles.AllowHexSpecifier, CultureInfo.InvariantCulture, out var value))
+                {
+                    return (value & mask) != 0;
+                }
+            }
+        }
+        catch
+        {
+            // If capability probing fails, keep test conservative.
+        }
+
+        return false;
+    }
+
+    private static bool TryCreateContext(out NftContext context)
+    {
+        try
+        {
+            context = new NftContext();
+            return true;
+        }
+        catch (DllNotFoundException)
+        {
+            context = null!;
+            return false;
+        }
+        catch (TypeInitializationException ex) when (ex.InnerException is DllNotFoundException)
+        {
+            context = null!;
+            return false;
+        }
+        catch (BadImageFormatException)
+        {
+            context = null!;
+            return false;
+        }
+        catch (EntryPointNotFoundException)
+        {
+            context = null!;
+            return false;
+        }
+    }
+}