fix: background reader apart from global handler for testing

cmd/syft/cli/ui/handle_attestation.go

@@ -21,12 +21,11 @@ import (
 )
 
 var (
-	_ tea.Model          = (*attestLogFrame)(nil)
-	_ cosignOutputReader = (*backgroundLineReader)(nil)
+	_ tea.Model = (*attestLogFrame)(nil)
 )
 
 type attestLogFrame struct {
-	reader     cosignOutputReader
+	reader     *backgroundLineReader
 	prog       progress.Progressable
 	lines      []string
 	completed  bool
@@ -47,14 +46,16 @@ type attestLogFrameTickMsg struct {
 	ID       uint32
 }
 
-type cosignOutputReader interface {
-	Lines() []string
-}
-
 type backgroundLineReader struct {
 	limit int
 	lines *queue.Queue[string]
 	lock  *sync.RWMutex
+
+	// This is added specifically for tests to assert when the background reader is done.
+	// The main UI uses the global ui wait group from the handler to otherwise block
+	// Shared concerns among multiple model made it difficult to test using the global wait group
+	// so this is added to allow tests to assert when the background reader is done.
+	running *sync.WaitGroup
 }
 
 func (m *Handler) handleAttestationStarted(e partybus.Event) []tea.Model {
@@ -97,7 +98,7 @@ func (m *Handler) handleAttestationStarted(e partybus.Event) []tea.Model {
 	}
 }
 
-func newLogFrame(reader cosignOutputReader, prog progress.Progressable, borderStyle lipgloss.Style) attestLogFrame {
+func newLogFrame(reader *backgroundLineReader, prog progress.Progressable, borderStyle lipgloss.Style) attestLogFrame {
 	return attestLogFrame{
 		reader:         reader,
 		prog:           prog,
@@ -108,16 +109,23 @@ func newLogFrame(reader cosignOutputReader, prog progress.Progressable, borderSt
 }
 
 func newBackgroundLineReader(wg *sync.WaitGroup, reader io.Reader, stage *progress.Stage) *backgroundLineReader {
-	wg.Add(1)
 	r := &backgroundLineReader{
-		limit: 7,
-		lock:  &sync.RWMutex{},
-		lines: queue.New[string](),
+		limit:   7,
+		lock:    &sync.RWMutex{},
+		lines:   queue.New[string](),
+		running: &sync.WaitGroup{},
 	}
 
+	// tracks the background reader for the global handler wait group
+	wg.Add(1)
+
+	// tracks the background reader for the local wait group (used in tests to decouple from the global handler wait group)
+	r.running.Add(1)
+
 	go func() {
-		defer wg.Done()
 		r.read(reader, stage)
+		wg.Done()
+		r.running.Done()
 	}()
 
 	return r

cmd/syft/cli/ui/handle_attestation_test.go

@@ -28,7 +28,7 @@ func TestHandler_handleAttestationStarted(t *testing.T) {
 			// note: this model depends on a background reader. Multiple iterations ensures that the
 			// reader has time to at least start and process the test fixture before the runModel
 			// test harness completes (which is a fake event loop anyway).
-			iterations: 100,
+			iterations: 1,
 			eventFn: func(t *testing.T) partybus.Event {
 				reader := strings.NewReader("contents\nof\nstuff!")
 
@@ -61,7 +61,7 @@ func TestHandler_handleAttestationStarted(t *testing.T) {
 			// note: this model depends on a background reader. Multiple iterations ensures that the
 			// reader has time to at least start and process the test fixture before the runModel
 			// test harness completes (which is a fake event loop anyway).
-			iterations: 100,
+			iterations: 1,
 			eventFn: func(t *testing.T) partybus.Event {
 				reader := strings.NewReader("contents\nof\nstuff!")
 
@@ -123,7 +123,7 @@ func TestHandler_handleAttestationStarted(t *testing.T) {
 					Time:     time.Now(),
 					Sequence: log.sequence,
 					ID:       log.id,
-				})
+				}, log.reader.running)
 				t.Log(got)
 				snaps.MatchSnapshot(t, got)
 			})

cmd/syft/cli/ui/util_test.go

@@ -2,13 +2,14 @@ package ui
 
 import (
 	"reflect"
+	"sync"
 	"testing"
 	"unsafe"
 
 	tea "github.com/charmbracelet/bubbletea"
 )
 
-func runModel(t testing.TB, m tea.Model, iterations int, message tea.Msg) string {
+func runModel(t testing.TB, m tea.Model, iterations int, message tea.Msg, h ...*sync.WaitGroup) string {
 	t.Helper()
 	if iterations == 0 {
 		iterations = 1
@@ -29,6 +30,12 @@ func runModel(t testing.TB, m tea.Model, iterations int, message tea.Msg) string
 		}
 		cmd = tea.Batch(nextCmds...)
 	}
+
+	for _, each := range h {
+		if each != nil {
+			each.Wait()
+		}
+	}
 	return m.View()
 }