mcp-ssh/tests/McpSsh.Tests/DefaultSshKeyResolverTests.cs

using McpSsh.Server.Ssh;

namespace McpSsh.Tests;

public sealed class DefaultSshKeyResolverTests
{
    [Fact]
    public void ResolveDefaultKeyPath_ReturnsFirstExistingDefaultKey()
    {
        var fileSystem = new FakeFileSystem("/home/test/.ssh/id_ecdsa", "/home/test/.ssh/id_rsa");
        var resolver = new DefaultSshKeyResolver(fileSystem, "/home/test/.ssh");

        var path = resolver.ResolveKeyPath(null);

        Assert.Equal("/home/test/.ssh/id_ecdsa", path);
    }

    [Fact]
    public void ResolveDefaultKeyPath_ThrowsWhenNoDefaultKeyExists()
    {
        var resolver = new DefaultSshKeyResolver(new FakeFileSystem(), "/home/test/.ssh");

        var ex = Assert.Throws<SshToolException>(() => resolver.ResolveKeyPath(null));

        Assert.Equal("ssh_key_not_found", ex.ErrorCode);
    }

    [Fact]
    public void ResolveKeyPath_ReturnsExplicitKeyWhenItExists()
    {
        var resolver = new DefaultSshKeyResolver(new FakeFileSystem("/keys/deploy_ed25519"), "/home/test/.ssh");

        var path = resolver.ResolveKeyPath("/keys/deploy_ed25519");

        Assert.Equal("/keys/deploy_ed25519", path);
    }

    [Fact]
    public void ResolveKeyPath_ThrowsWhenExplicitKeyDoesNotExist()
    {
        var resolver = new DefaultSshKeyResolver(new FakeFileSystem(), "/home/test/.ssh");

        var ex = Assert.Throws<SshToolException>(() => resolver.ResolveKeyPath("/keys/missing"));

        Assert.Equal("ssh_key_not_found", ex.ErrorCode);
    }

    private sealed class FakeFileSystem : IFileSystem
    {
        private readonly HashSet<string> _paths;

        public FakeFileSystem(params string[] paths)
        {
            _paths = paths.ToHashSet(StringComparer.Ordinal);
        }

        public bool FileExists(string path) => _paths.Contains(path);
    }
}