kenn-io--agentsview/internal/server/usage_readonly_internal_test.go

package server

import (
	"context"
	"net/http"
	"testing"

	"go.kenn.io/agentsview/internal/db"
)

// readOnlyUsageSpy stubs the Store interface and returns
// db.ErrReadOnly from the three usage queries. It lets us
// verify the handlers map the sentinel error to 501 Not
// Implemented without spinning up a real PG instance.
type readOnlyUsageSpy struct {
	db.Store
}

func (readOnlyUsageSpy) GetDailyUsage(
	_ context.Context, _ db.UsageFilter,
) (db.DailyUsageResult, error) {
	return db.DailyUsageResult{}, db.ErrReadOnly
}

func (readOnlyUsageSpy) GetTopSessionsByCost(
	_ context.Context, _ db.UsageFilter, _ int,
) ([]db.TopSessionEntry, error) {
	return nil, db.ErrReadOnly
}

func (readOnlyUsageSpy) GetUsageSessionCounts(
	_ context.Context, _ db.UsageFilter,
) (db.UsageSessionCounts, error) {
	return db.UsageSessionCounts{}, db.ErrReadOnly
}

func (readOnlyUsageSpy) GetUsageMatchingSessionCount(
	_ context.Context, _ db.UsageFilter,
) (int, error) {
	return 0, db.ErrReadOnly
}

// TestUsageHandlers_ReturnNotImplementedOnReadOnlyStore locks
// in the Postgres-backend contract: when the underlying Store
// reports a usage query as unavailable (db.ErrReadOnly), both
// usage HTTP endpoints must surface 501 Not Implemented rather
// than silently returning an empty body, which would look like
// "no usage data" to the user.
func TestUsageHandlers_ReturnNotImplementedOnReadOnlyStore(
	t *testing.T,
) {
	s := newRoutedTestServerWithStore(t, readOnlyUsageSpy{})

	cases := []struct {
		name string
		path string
	}{
		{
			name: "summary",
			path: "/api/v1/usage/summary?" +
				"from=2024-06-01&to=2024-06-03",
		},
		{
			name: "top-sessions",
			path: "/api/v1/usage/top-sessions?" +
				"from=2024-06-01&to=2024-06-03",
		},
		{
			name: "pairwise",
			path: "/api/v1/usage/pairwise-comparison?" +
				"from=2024-06-01&to=2024-06-03&left_dimension=model&left_value=claude-sonnet-4-20250514&right_dimension=project&right_value=beta",
		},
	}
	for _, tc := range cases {
		t.Run(tc.name, func(t *testing.T) {
			w := serveGet(t, s, tc.path)
			assertRecorderStatus(t, w, http.StatusNotImplemented)
		})
	}
}