gitea-mcp/internal/mcp/audit_test.go

package mcp_test

import (
	"bytes"
	"context"
	"encoding/json"
	"errors"
	"log/slog"
	"net/http"
	"net/http/httptest"
	"strings"
	"testing"

	"git.d-ma.be/mathias/gitea-mcp/internal/auth"
	"git.d-ma.be/mathias/gitea-mcp/internal/mcp"
	"git.d-ma.be/mathias/gitea-mcp/internal/registry"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
)

type auditStubTool struct {
	name string
	err  error
}

func (s auditStubTool) Descriptor() registry.ToolDescriptor {
	return registry.ToolDescriptor{Name: s.name, InputSchema: json.RawMessage(`{"type":"object"}`)}
}

func (s auditStubTool) Call(context.Context, json.RawMessage) (json.RawMessage, error) {
	if s.err != nil {
		return nil, s.err
	}
	return json.RawMessage(`{"ok":true}`), nil
}

// captureAudit routes slog to a buffer and returns the decoded
// "mcp tool call" records emitted while fn runs.
func captureAudit(t *testing.T, fn func()) []map[string]any {
	t.Helper()
	var buf bytes.Buffer
	prev := slog.Default()
	slog.SetDefault(slog.New(slog.NewJSONHandler(&buf, nil)))
	t.Cleanup(func() { slog.SetDefault(prev) })

	fn()

	var out []map[string]any
	for _, l := range strings.Split(strings.TrimSpace(buf.String()), "\n") {
		if l == "" {
			continue
		}
		var rec map[string]any
		require.NoError(t, json.Unmarshal([]byte(l), &rec))
		if rec["msg"] == "mcp tool call" {
			out = append(out, rec)
		}
	}
	return out
}

func auditServer(tools ...registry.Tool) http.Handler {
	reg := registry.New()
	for _, tl := range tools {
		reg.Register(tl)
	}
	srv := mcp.NewServer(mcp.ServerOptions{Registry: reg})
	return auth.CallerMiddleware(slog.Default(), srv)
}

func callTool(t *testing.T, h http.Handler, name string, args any) {
	t.Helper()
	body := map[string]any{
		"jsonrpc": "2.0", "id": 1, "method": "tools/call",
		"params": map[string]any{"name": name, "arguments": args},
	}
	b, err := json.Marshal(body)
	require.NoError(t, err)
	req := httptest.NewRequest(http.MethodPost, "/", bytes.NewBuffer(b))
	req.Header.Set("Content-Type", "application/json")
	req.Header.Set("X-Auth-Request-User", "alice")
	h.ServeHTTP(httptest.NewRecorder(), req)
}

// gitea-mcp#64: tools/call dispatched with no record at all.
func TestToolsCallLogsOneAuditRecordWithToolCallerAndTarget(t *testing.T) {
	recs := captureAudit(t, func() {
		callTool(t, auditServer(auditStubTool{name: "repo_delete"}), "repo_delete",
			map[string]any{"owner": "mathias", "repo": "scratch", "confirm": "scratch"})
	})
	require.Len(t, recs, 1)
	r := recs[0]
	assert.Equal(t, "repo_delete", r["tool"])
	assert.Equal(t, "alice", r["caller"])
	assert.Equal(t, "mathias", r["owner"])
	assert.Equal(t, "scratch", r["repo"])
	assert.Equal(t, "ok", r["outcome"])
	assert.Contains(t, r, "duration_ms")
}

func TestToolsCallAuditRecordsErrorOutcome(t *testing.T) {
	recs := captureAudit(t, func() {
		callTool(t, auditServer(auditStubTool{name: "pr_merge", err: errors.New("boom")}),
			"pr_merge", map[string]any{"owner": "mathias", "repo": "x", "number": 3})
	})
	require.Len(t, recs, 1)
	assert.Equal(t, "boom", recs[0]["outcome"])
	assert.EqualValues(t, 3, recs[0]["number"])
}

// The audit line must not become a second copy of repo content.
func TestToolsCallAuditOmitsArgumentValuesOtherThanTarget(t *testing.T) {
	const sentinel = "SENTINEL-FILE-CONTENT-7f3a"
	recs := captureAudit(t, func() {
		callTool(t, auditServer(auditStubTool{name: "file_write_branch"}), "file_write_branch",
			map[string]any{"owner": "mathias", "repo": "x", "path": "a.txt", "content": sentinel})
	})
	require.Len(t, recs, 1)
	raw, err := json.Marshal(recs[0])
	require.NoError(t, err)
	assert.NotContains(t, string(raw), sentinel)
	assert.Contains(t, recs[0], "args_bytes")
}