Render templates via a buffer, not the ResponseWriter (closes #123)

executeTemplate ran the template straight into the ResponseWriter, so a
mid-render failure left the already-emitted prefix written and the
response committed: the handler could no longer set a 500 and the
client got a truncated page, typically with a 200. It also let handler
tests pass against the flushed prefix of a page that aborted below the
assertions.

Execute into a bytes.Buffer instead, and set the content type and copy
the buffer out only once rendering has fully succeeded. On failure
nothing has been written, so the 500 still reaches the client.

Add a test that renders a template failing partway through and asserts
both the 500 and that the body carries no part of the aborted page.
Against the previous streaming renderer it fails on both counts (200,
body "PARTIAL PAGE CONTENTInternal server error").

internal/database/export_test.go

@@ -46,19 +46,8 @@ func (r *RetentionReaper) ExportStart() {
 }
 
 // ExportStop stops the reaper's background loop for tests.
-func (r *RetentionReaper) ExportStop(ctx context.Context) error {
-	return r.stop(ctx)
-}
-
-// ExportWedgeLoop adds a goroutine to the reaper's WaitGroup that
-// never observes cancellation and returns only when release is
-// closed. It stands in for a sweep stuck on a locked database.
-func (r *RetentionReaper) ExportWedgeLoop(
-	release <-chan struct{},
-) {
-	r.wg.Go(func() {
-		<-release
-	})
+func (r *RetentionReaper) ExportStop() {
+	r.stop()
 }
 
 // ExportSetInterval overrides the sweep interval for tests.

internal/database/retention.go

@@ -10,7 +10,6 @@ import (
 	"go.uber.org/fx"
 	"gorm.io/gorm"
 	"sneak.berlin/go/webhooker/internal/config"
-	"sneak.berlin/go/webhooker/internal/lifecycle"
 	"sneak.berlin/go/webhooker/internal/logger"
 )
 
@@ -63,9 +62,8 @@ func NewRetentionReaper(
 }
 
 // registerHooks wires the reaper's start and stop into the fx
-// lifecycle. The start hook's context is deliberately ignored (see
-// start for why the sweep loop must not inherit it); the stop hook's
-// context is honoured (see stop).
+// lifecycle. The start hook's context is deliberately ignored: see
+// start for why the sweep loop must not inherit it.
 func (r *RetentionReaper) registerHooks(lc fx.Lifecycle) {
 	lc.Append(fx.Hook{
 		//nolint:contextcheck // Not inheriting the hook context is
@@ -75,8 +73,10 @@ func (r *RetentionReaper) registerHooks(lc fx.Lifecycle) {
 
 			return nil
 		},
-		OnStop: func(ctx context.Context) error {
-			return r.stop(ctx)
+		OnStop: func(_ context.Context) error {
+			r.stop()
+
+			return nil
 		},
 	})
 }
@@ -105,27 +105,15 @@ func (r *RetentionReaper) start() {
 	)
 }
 
-// stop cancels the sweep loop's context and waits for it to
-// exit, bounded by the stop hook's context: a sweep wedged on a
-// locked database must not hang the process past fx's stop
-// timeout.
-func (r *RetentionReaper) stop(ctx context.Context) error {
+func (r *RetentionReaper) stop() {
 	r.log.Info("retention reaper stopping")
 
 	if r.cancel != nil {
 		r.cancel()
 	}
 
-	err := lifecycle.WaitForShutdown(
-		ctx, r.log, "retention reaper", &r.wg,
-	)
-	if err != nil {
-		return err
-	}
-
+	r.wg.Wait()
 	r.log.Info("retention reaper stopped")
-
-	return nil
 }
 
 func (r *RetentionReaper) run(ctx context.Context) {

internal/database/retention_lifecycle_test.go

@@ -26,13 +26,6 @@ const (
 	// reaperTestRetentionDays is the retention policy the lifecycle
 	// tests give their webhook.
 	reaperTestRetentionDays = 30
-
-	// reaperWedgeStopTimeout is the stop timeout the wedged-shutdown
-	// test hands OnStop, standing in for fx's StopTimeout. The test
-	// asserts only that the hook returns at all, and allows it
-	// reaperStopTimeout — forty times this budget — to do so, so no
-	// assertion races the wall clock.
-	reaperWedgeStopTimeout = 250 * time.Millisecond
 )
 
 // recordingLifecycle is a minimal fx.Lifecycle that records the
@@ -214,59 +207,3 @@ func TestRetentionReaper_StopHookStopsLoop(t *testing.T) {
 		"a stopped reaper must not sweep anything",
 	)
 }
-
-// TestRetentionReaper_StopHookHonoursStopTimeout is the
-// regression test for a shutdown that could never complete. fx
-// hands OnStop a context carrying the application's stop timeout;
-// an OnStop that discards it and calls wg.Wait() bare hangs the
-// process forever on a sweep blocked on a locked SQLite database
-// — precisely when a bounded shutdown matters most.
-//
-// The wedged goroutine here never observes cancellation, so the
-// hook can only return by honouring its context, and it must say
-// so rather than reporting a clean stop.
-func TestRetentionReaper_StopHookHonoursStopTimeout(
-	t *testing.T,
-) {
-	t.Parallel()
-
-	env := setupRetentionTest(t)
-
-	env.reaper.ExportSetInterval(reaperTestInterval)
-
-	lc := startReaperViaHook(t, env.reaper)
-
-	release := make(chan struct{})
-
-	t.Cleanup(func() { close(release) })
-
-	env.reaper.ExportWedgeLoop(release)
-
-	stopCtx, cancel := context.WithTimeout(
-		context.Background(), reaperWedgeStopTimeout,
-	)
-	defer cancel()
-
-	var stopErr error
-
-	stopped := make(chan struct{})
-
-	go func() {
-		defer close(stopped)
-
-		stopErr = lc.hooks[0].OnStop(stopCtx)
-	}()
-
-	select {
-	case <-stopped:
-	case <-time.After(reaperStopTimeout):
-		t.Fatal(
-			"OnStop did not return: it discarded the stop " +
-				"context and is waiting on a wedged goroutine " +
-				"that will never observe cancellation",
-		)
-	}
-
-	require.ErrorIs(t, stopErr, context.DeadlineExceeded)
-	require.ErrorContains(t, stopErr, "retention reaper")
-}

internal/delivery/archive_sweeper.go

@@ -10,7 +10,6 @@ import (
 	"go.uber.org/fx"
 	"sneak.berlin/go/webhooker/internal/config"
 	"sneak.berlin/go/webhooker/internal/database"
-	"sneak.berlin/go/webhooker/internal/lifecycle"
 	"sneak.berlin/go/webhooker/internal/logger"
 )
 
@@ -68,9 +67,10 @@ func NewArchiveSweeper(
 }
 
 // registerHooks wires the sweeper's start and stop into the fx
-// lifecycle. The start hook's context is deliberately ignored
-// (see start for why the background loop must not inherit it);
-// the stop hook's context is honoured (see stop).
+// lifecycle. Both hook contexts are deliberately ignored: see
+// start for why the background loop must not inherit the start
+// hook's context, and stop for why shutdown blocks on the loop
+// rather than on the stop hook's deadline.
 func (s *ArchiveSweeper) registerHooks(lc fx.Lifecycle) {
 	lc.Append(fx.Hook{
 		//nolint:contextcheck // Not passing the hook context is
@@ -80,8 +80,10 @@ func (s *ArchiveSweeper) registerHooks(lc fx.Lifecycle) {
 
 			return nil
 		},
-		OnStop: func(ctx context.Context) error {
-			return s.stop(ctx)
+		OnStop: func(_ context.Context) error {
+			s.stop()
+
+			return nil
 		},
 	})
 }
@@ -111,27 +113,15 @@ func (s *ArchiveSweeper) start() {
 	)
 }
 
-// stop cancels the sweep loop's context and waits for it to
-// exit, bounded by the stop hook's context: a prune wedged on a
-// locked archive must not hang the process past fx's stop
-// timeout.
-func (s *ArchiveSweeper) stop(ctx context.Context) error {
+func (s *ArchiveSweeper) stop() {
 	s.log.Info("archive sweeper stopping")
 
 	if s.cancel != nil {
 		s.cancel()
 	}
 
-	err := lifecycle.WaitForShutdown(
-		ctx, s.log, "archive sweeper", &s.wg,
-	)
-	if err != nil {
-		return err
-	}
-
+	s.wg.Wait()
 	s.log.Info("archive sweeper stopped")
-
-	return nil
 }
 
 func (s *ArchiveSweeper) run(ctx context.Context) {

internal/delivery/archive_sweeper_test.go

@@ -14,6 +14,7 @@ import (
 	"github.com/google/uuid"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
+	"go.uber.org/fx"
 	"gorm.io/driver/sqlite"
 	"gorm.io/gorm"
 	"gorm.io/gorm/clause"
@@ -225,6 +226,17 @@ func countArchivedRows(path string) (int64, error) {
 	return count, nil
 }
 
+// captureLifecycle is a minimal fx.Lifecycle that records the
+// hooks a component registers, so a test can invoke the real
+// OnStart/OnStop functions with a context of its choosing.
+type captureLifecycle struct {
+	hooks []fx.Hook
+}
+
+func (l *captureLifecycle) Append(h fx.Hook) {
+	l.hooks = append(l.hooks, h)
+}
+
 // TestArchiveSweeper_LoopOutlivesStartHookContext is the
 // regression test for a sweeper that never swept. fx calls
 // OnStart with a context carrying the application's start
@@ -258,7 +270,7 @@ func TestArchiveSweeper_LoopOutlivesStartHookContext(
 
 	// Drive the genuine fx hooks the application registers,
 	// rather than a test-only entry point.
-	lc := &recordingLifecycle{}
+	lc := &captureLifecycle{}
 	env.sweeper.ExportRegisterHooks(lc)
 	require.Len(t, lc.hooks, 1)
 
@@ -912,36 +924,7 @@ func TestArchiveSweeper_StopsCleanly(t *testing.T) {
 	env.sweeper.ExportSetInterval(time.Millisecond)
 	env.sweeper.ExportStart()
 
-	// stop blocks on the loop's WaitGroup, so returning without
-	// error proves the loop observed the cancellation and exited
-	// well inside the stop context.
-	require.NoError(
-		t, env.sweeper.ExportStop(context.Background()),
-	)
-}
-
-// TestArchiveSweeper_StopHookHonoursStopTimeout is the sweeper's
-// half of the same shutdown defect the engine and the retention
-// reaper carried: an OnStop that discards its context and waits
-// on the WaitGroup bare hangs the process forever on a prune
-// wedged inside a locked archive.
-func TestArchiveSweeper_StopHookHonoursStopTimeout(
-	t *testing.T,
-) {
-	t.Parallel()
-
-	env := setupSweeperTest(t)
-
-	lc := &recordingLifecycle{}
-	env.sweeper.ExportRegisterHooks(lc)
-	require.Len(t, lc.hooks, 1)
-	require.NoError(t, lc.hooks[0].OnStart(context.Background()))
-
-	release := make(chan struct{})
-
-	t.Cleanup(func() { close(release) })
-
-	env.sweeper.ExportWedgeLoop(release)
-
-	requireStopHookExpires(t, lc.hooks[0], "archive sweeper")
+	// stop blocks on the loop's WaitGroup, so returning at all
+	// proves the loop observed the cancellation and exited.
+	env.sweeper.ExportStop()
 }

internal/delivery/engine.go

@@ -13,7 +13,6 @@ import (
 	"go.uber.org/fx"
 	"gorm.io/gorm"
 	"sneak.berlin/go/webhooker/internal/database"
-	"sneak.berlin/go/webhooker/internal/lifecycle"
 	"sneak.berlin/go/webhooker/internal/logger"
 )
 
@@ -235,9 +234,8 @@ func (e *Engine) ScheduleRetry(
 }
 
 // registerHooks wires the engine's start and stop into the fx
-// lifecycle. The start hook's context is deliberately ignored
-// (see start for why the worker pool must not inherit it); the
-// stop hook's context is honoured (see stop).
+// lifecycle. The start hook's context is deliberately ignored:
+// see start for why the worker pool must not inherit it.
 func (e *Engine) registerHooks(lc fx.Lifecycle) {
 	lc.Append(fx.Hook{
 		//nolint:contextcheck // Not inheriting the hook context
@@ -247,8 +245,10 @@ func (e *Engine) registerHooks(lc fx.Lifecycle) {
 
 			return nil
 		},
-		OnStop: func(ctx context.Context) error {
-			return e.stop(ctx)
+		OnStop: func(_ context.Context) error {
+			e.stop()
+
+			return nil
 		},
 	})
 }
@@ -289,26 +289,11 @@ func (e *Engine) start() {
 	)
 }
 
-// stop cancels the worker pool's context and waits for the pool
-// to drain, bounded by the stop hook's context: a wedged worker
-// must not hang the process past fx's stop timeout.
-func (e *Engine) stop(ctx context.Context) error {
+func (e *Engine) stop() {
 	e.log.Info("delivery engine stopping")
-
-	if e.cancel != nil {
 	e.cancel()
-	}
-
-	err := lifecycle.WaitForShutdown(
-		ctx, e.log, "delivery engine", &e.wg,
-	)
-	if err != nil {
-		return err
-	}
-
+	e.wg.Wait()
 	e.log.Info("delivery engine stopped")
-
-	return nil
 }
 
 func (e *Engine) worker(ctx context.Context) {

internal/delivery/engine_integration_test.go

@@ -501,7 +501,7 @@ func TestWorkerLifecycle_StartStop(t *testing.T) {
 
 	iWaitForDelivered(t, s.WebhookDB, d.ID)
 
-	require.NoError(t, s.Engine.ExportStop(context.Background()))
+	s.Engine.ExportStop()
 }
 
 // iWaitForDelivered polls until the delivery reaches the
@@ -567,7 +567,7 @@ func TestWorkerLifecycle_ProcessesRetryChannel(
 
 	iWaitForDelivered(t, s.WebhookDB, d.ID)
 
-	require.NoError(t, s.Engine.ExportStop(context.Background()))
+	s.Engine.ExportStop()
 }
 
 // --- processDelivery: unknown target type ---

internal/delivery/engine_lifecycle_test.go

@@ -27,13 +27,6 @@ const (
 	// and a ready deliveryCh are chosen between at random and a
 	// doomed pool still delivers.
 	hookSettleDelay = 250 * time.Millisecond
-
-	// wedgeStopTimeout is the stop timeout a wedged-shutdown test
-	// hands OnStop, standing in for fx's StopTimeout. The test
-	// asserts only that the hook returns at all, and allows it
-	// hookStopTimeout — forty times this budget — to do so, so no
-	// assertion here races the wall clock.
-	wedgeStopTimeout = 250 * time.Millisecond
 )
 
 // recordingLifecycle is a minimal fx.Lifecycle that records the
@@ -47,44 +40,6 @@ func (l *recordingLifecycle) Append(h fx.Hook) {
 	l.hooks = append(l.hooks, h)
 }
 
-// requireStopHookExpires drives hook.OnStop with a stop context
-// that expires while a wedged goroutine is still running, and
-// requires the hook to return the deadline error naming
-// component instead of blocking on the WaitGroup forever.
-func requireStopHookExpires(
-	t *testing.T, hook fx.Hook, component string,
-) {
-	t.Helper()
-
-	stopCtx, cancel := context.WithTimeout(
-		context.Background(), wedgeStopTimeout,
-	)
-	defer cancel()
-
-	var stopErr error
-
-	stopped := make(chan struct{})
-
-	go func() {
-		defer close(stopped)
-
-		stopErr = hook.OnStop(stopCtx)
-	}()
-
-	select {
-	case <-stopped:
-	case <-time.After(hookStopTimeout):
-		t.Fatal(
-			"OnStop did not return: it discarded the stop " +
-				"context and is waiting on a wedged goroutine " +
-				"that will never observe cancellation",
-		)
-	}
-
-	require.ErrorIs(t, stopErr, context.DeadlineExceeded)
-	require.ErrorContains(t, stopErr, component)
-}
-
 // startEngineViaHook drives the genuine fx hooks the application
 // registers for the engine, handing OnStart a context that is
 // already done, and returns only once a pool that inherited that
@@ -242,30 +197,3 @@ func TestEngine_StopHookStopsWorkers(t *testing.T) {
 		"a stopped engine must not deliver anything",
 	)
 }
-
-// TestEngine_StopHookHonoursStopTimeout is the regression test
-// for a shutdown that could never complete. fx hands OnStop a
-// context carrying the application's stop timeout; an OnStop
-// that discards it and calls wg.Wait() bare hangs the process
-// forever on a single worker stuck inside a delivery target that
-// never returns — precisely when a bounded shutdown matters
-// most.
-//
-// The wedged goroutine here never observes cancellation, so the
-// hook can only return by honouring its context, and it must say
-// so rather than reporting a clean stop.
-func TestEngine_StopHookHonoursStopTimeout(t *testing.T) {
-	t.Parallel()
-
-	s := newISetup(t)
-
-	lc := startEngineViaHook(t, s.Engine)
-
-	release := make(chan struct{})
-
-	t.Cleanup(func() { close(release) })
-
-	s.Engine.ExportWedgeWorker(release)
-
-	requireStopHookExpires(t, lc.hooks[0], "delivery engine")
-}

internal/delivery/export_test.go

@@ -216,19 +216,8 @@ func (e *Engine) ExportRegisterHooks(lc fx.Lifecycle) {
 }
 
 // ExportStop exposes stop for testing.
-func (e *Engine) ExportStop(ctx context.Context) error {
-	return e.stop(ctx)
-}
-
-// ExportWedgeWorker adds a goroutine to the engine's WaitGroup
-// that never observes cancellation and returns only when release
-// is closed. It stands in for a worker stuck inside a delivery
-// target that never returns, which is the only way stop can be
-// made to outlast its context.
-func (e *Engine) ExportWedgeWorker(release <-chan struct{}) {
-	e.wg.Go(func() {
-		<-release
-	})
+func (e *Engine) ExportStop() {
+	e.stop()
 }
 
 // ExportDeliveryCh returns the delivery channel.
@@ -529,19 +518,8 @@ func (s *ArchiveSweeper) ExportRegisterHooks(lc fx.Lifecycle) {
 }
 
 // ExportStop stops the sweeper's background loop for tests.
-func (s *ArchiveSweeper) ExportStop(ctx context.Context) error {
-	return s.stop(ctx)
-}
-
-// ExportWedgeLoop adds a goroutine to the sweeper's WaitGroup
-// that never observes cancellation and returns only when release
-// is closed. It stands in for a prune stuck on a locked archive.
-func (s *ArchiveSweeper) ExportWedgeLoop(
-	release <-chan struct{},
-) {
-	s.wg.Go(func() {
-		<-release
-	})
+func (s *ArchiveSweeper) ExportStop() {
+	s.stop()
 }
 
 // ExportSetInterval overrides the sweep interval for tests.

internal/handlers/export_test.go

@@ -1,6 +1,19 @@
 package handlers
 
-import "net/http"
+import (
+	"html/template"
+	"net/http"
+)
+
+// AddTemplateForTest registers a template under a page name so that
+// the handlers_test package can drive the render path with a
+// template of its own.
+func (s *Handlers) AddTemplateForTest(
+	pageTemplate string,
+	tmpl *template.Template,
+) {
+	s.templates[pageTemplate] = tmpl
+}
 
 // RenderTemplateForTest exposes renderTemplate for use in the
 // handlers_test package.

internal/handlers/handlers.go

@@ -3,6 +3,7 @@
 package handlers
 
 import (
+	"bytes"
 	"context"
 	"encoding/json"
 	"errors"
@@ -224,13 +225,20 @@ func (s *Handlers) renderTemplate(
 	s.executeTemplate(w, tmpl, wrapper)
 }
 
-// executeTemplate runs the template and handles errors.
+// executeTemplate renders the template into a buffer and writes to
+// the response only once rendering has fully succeeded. Executing
+// straight into the ResponseWriter commits a partial body and a 200
+// status before a mid-render error can be reported, leaving no way
+// to serve a 500. These pages are small, so holding one in memory is
+// the right trade.
 func (s *Handlers) executeTemplate(
 	w http.ResponseWriter,
 	tmpl *template.Template,
 	data any,
 ) {
-	err := tmpl.Execute(w, data)
+	var buf bytes.Buffer
+
+	err := tmpl.Execute(&buf, data)
 	if err != nil {
 		s.log.Error(
 			"failed to execute template", "error", err,
@@ -239,5 +247,16 @@ func (s *Handlers) executeTemplate(
 			w, "Internal server error",
 			http.StatusInternalServerError,
 		)
+
+		return
+	}
+
+	w.Header().Set("Content-Type", "text/html; charset=utf-8")
+
+	_, err = buf.WriteTo(w)
+	if err != nil {
+		s.log.Error(
+			"failed to write rendered page", "error", err,
+		)
 	}
 }

internal/handlers/handlers_test.go

@@ -2,6 +2,8 @@ package handlers_test
 
 import (
 	"context"
+	"errors"
+	"html/template"
 	"net/http"
 	"net/http/httptest"
 	"sync"
@@ -220,6 +222,68 @@ func TestRenderTemplate(t *testing.T) {
 	)
 }
 
+// errMidRender is the failure a test template raises partway through
+// rendering.
+var errMidRender = errors.New("deliberate mid-render failure")
+
+// midRenderFailure is template data whose first method renders and
+// whose second fails, so the template aborts after output has
+// already been produced.
+type midRenderFailure struct{}
+
+// Prefix is the output a streaming renderer would flush before the
+// failure below aborts the template.
+func (midRenderFailure) Prefix() string { return partialPageMarker }
+
+// Boom aborts template execution.
+func (midRenderFailure) Boom() (string, error) {
+	return "", errMidRender
+}
+
+// partialPageMarker is content the failing template emits before it
+// aborts.
+const partialPageMarker = "PARTIAL PAGE CONTENT"
+
+// TestRenderTemplateMidRenderErrorSendsNoPartialBody proves the
+// renderer does not commit output it cannot finish: a template that
+// fails partway through must yield a 500 and a body carrying none of
+// the content emitted before the failure. Against a renderer that
+// executes straight into the ResponseWriter this fails on both
+// counts, returning 200 with the prefix already flushed.
+func TestRenderTemplateMidRenderErrorSendsNoPartialBody(t *testing.T) {
+	t.Parallel()
+
+	var h *handlers.Handlers
+
+	app := newTestApp(t, &h)
+	app.RequireStart()
+
+	t.Cleanup(app.RequireStop)
+
+	h.AddTemplateForTest("failing.html", template.Must(
+		template.New("failing").Parse(
+			`{{.Data.Prefix}}{{.Data.Boom}}TAIL`,
+		),
+	))
+
+	req := httptest.NewRequestWithContext(
+		context.Background(), http.MethodGet, "/", nil)
+	w := httptest.NewRecorder()
+
+	h.RenderTemplateForTest(
+		w, req, "failing.html", midRenderFailure{},
+	)
+
+	assert.Equal(
+		t, http.StatusInternalServerError, w.Code,
+		"a failed render must report a 500",
+	)
+	assert.Equal(
+		t, "Internal server error\n", w.Body.String(),
+		"the response must carry no part of the aborted page",
+	)
+}
+
 func TestBuildDatabaseTargetConfig_Valid(t *testing.T) {
 	t.Parallel()
 

internal/lifecycle/lifecycle.go

@@ -1,57 +0,0 @@
-// Package lifecycle holds helpers shared by the components that
-// register fx start and stop hooks.
-package lifecycle
-
-import (
-	"context"
-	"fmt"
-	"log/slog"
-	"sync"
-)
-
-// WaitForShutdown waits for wg to drain, bounded by ctx.
-//
-// fx hands OnStop a context carrying the application's stop
-// timeout. A bare wg.Wait() discards that deadline, so a single
-// goroutine that never observes cancellation — a delivery target
-// that never returns, a SQLite operation blocked on a lock —
-// hangs the process forever instead of letting it exit when the
-// timeout expires, which is exactly when a clean shutdown matters
-// most.
-//
-// On timeout it logs at error naming component and returns an
-// error: the goroutines are still running, and reporting success
-// would hide an unclean shutdown from the operator. The waiting
-// goroutine outlives this call and exits when (if) wg drains; it
-// holds nothing but the channel it closes.
-func WaitForShutdown(
-	ctx context.Context,
-	log *slog.Logger,
-	component string,
-	wg *sync.WaitGroup,
-) error {
-	done := make(chan struct{})
-
-	go func() {
-		defer close(done)
-
-		wg.Wait()
-	}()
-
-	select {
-	case <-done:
-		return nil
-	case <-ctx.Done():
-		log.Error(
-			"shutdown timed out, goroutines still running",
-			"component", component,
-			"error", ctx.Err(),
-		)
-
-		return fmt.Errorf(
-			"%s: shutdown timed out, "+
-				"goroutines still running: %w",
-			component, ctx.Err(),
-		)
-	}
-}

internal/lifecycle/lifecycle_test.go

@@ -1,62 +0,0 @@
-package lifecycle_test
-
-import (
-	"context"
-	"log/slog"
-	"sync"
-	"testing"
-	"time"
-
-	"github.com/stretchr/testify/require"
-	"sneak.berlin/go/webhooker/internal/lifecycle"
-)
-
-// waitTimeout is the stop budget the timeout case gives a
-// goroutine that never returns. The test's own patience is the
-// go test deadline, so the only thing this value affects is how
-// long the case takes.
-const waitTimeout = 100 * time.Millisecond
-
-func discardLogger() *slog.Logger {
-	return slog.New(slog.DiscardHandler)
-}
-
-func TestWaitForShutdown_DrainedGroup(t *testing.T) {
-	t.Parallel()
-
-	var wg sync.WaitGroup
-
-	wg.Go(func() {})
-
-	require.NoError(
-		t,
-		lifecycle.WaitForShutdown(
-			context.Background(), discardLogger(),
-			"test component", &wg,
-		),
-	)
-}
-
-func TestWaitForShutdown_ContextExpires(t *testing.T) {
-	t.Parallel()
-
-	release := make(chan struct{})
-
-	t.Cleanup(func() { close(release) })
-
-	var wg sync.WaitGroup
-
-	wg.Go(func() { <-release })
-
-	ctx, cancel := context.WithTimeout(
-		context.Background(), waitTimeout,
-	)
-	defer cancel()
-
-	err := lifecycle.WaitForShutdown(
-		ctx, discardLogger(), "test component", &wg,
-	)
-
-	require.ErrorIs(t, err, context.DeadlineExceeded)
-	require.ErrorContains(t, err, "test component")
-}