test(agentcompat): add process supervision harness

Co-authored-by: naiba/CloudCode <hi+cloudcode@nai.ba>

integration/agentcompat/internal/process/sqlite_journal_watch_test.go

@@ -0,0 +1,186 @@
+//go:build linux
+
+package process
+
+import (
+	"context"
+	"errors"
+	"os"
+	"path/filepath"
+	"testing"
+	"time"
+
+	"golang.org/x/sys/unix"
+)
+
+func TestSQLiteJournalWatch_CapturesExactIdentityAndCloses(t *testing.T) {
+	// Given
+	path := writeJournal(t, "dashboard.sqlite-journal")
+	watch, err := OpenSQLiteJournalWatch(path)
+	requireNoError(t, err)
+	t.Cleanup(func() { requireNoError(t, watch.Close()) })
+
+	// When
+	identity := watch.Identity()
+
+	// Then
+	if identity.MountID == 0 || identity.Inode == 0 || identity.BirthTime.Sec == 0 {
+		t.Fatalf("identity = %#v, want complete statx identity", identity)
+	}
+	if err := watch.Verify(); err != nil {
+		t.Fatalf("verify identity: %v", err)
+	}
+	journalFD, inotifyFD := watch.journalFD, watch.inotifyFD
+	requireNoError(t, watch.Close())
+	requireNoError(t, watch.Close())
+	if _, err := unix.FcntlInt(uintptr(journalFD), unix.F_GETFD, 0); !errors.Is(err, unix.EBADF) {
+		t.Fatalf("journal descriptor remains open: %v", err)
+	}
+	if _, err := unix.FcntlInt(uintptr(inotifyFD), unix.F_GETFD, 0); !errors.Is(err, unix.EBADF) {
+		t.Fatalf("inotify descriptor remains open: %v", err)
+	}
+}
+
+func TestSQLiteJournalWatch_RejectsReplacementPathDrift(t *testing.T) {
+	// Given
+	path := writeJournal(t, "dashboard.sqlite-journal")
+	watch, err := OpenSQLiteJournalWatch(path)
+	requireNoError(t, err)
+	t.Cleanup(func() { requireNoError(t, watch.Close()) })
+	replacement := filepath.Join(filepath.Dir(path), "replacement")
+	requireNoError(t, os.WriteFile(replacement, []byte("replacement"), 0o600))
+	requireNoError(t, os.Rename(replacement, path))
+
+	// When
+	err = watch.Verify()
+
+	// Then
+	if !errors.Is(err, ErrSQLiteJournalIdentityMismatch) {
+		t.Fatalf("verify error = %v, want identity mismatch", err)
+	}
+}
+
+func TestSQLiteJournalWatch_VerifiesIdentityForEveryWindowSample(t *testing.T) {
+	// Given
+	path := writeJournal(t, "dashboard.sqlite-journal")
+	watch, err := OpenSQLiteJournalWatch(path)
+	requireNoError(t, err)
+	t.Cleanup(func() { requireNoError(t, watch.Close()) })
+	verified := 0
+
+	// When
+	window, err := SampleWindow(t.Context(), WindowSpec{PID: os.Getpid(), Interval: time.Millisecond, ObserveSample: func(ctx context.Context, sample Sample) error {
+		verified++
+		return watch.ObserveSample(ctx, sample)
+	}})
+
+	// Then
+	requireNoError(t, err)
+	if len(window.Samples) != 5 || verified != 5 {
+		t.Fatalf("samples = %d, verified = %d, want 5", len(window.Samples), verified)
+	}
+}
+
+func TestSQLiteJournalIdentity_RejectsMissingRequiredStatxMask(t *testing.T) {
+	// Given
+	stat := unix.Statx_t{Mask: unix.STATX_MNT_ID, Mnt_id: 1, Ino: 2}
+
+	// When / Then
+	if _, err := sqliteJournalIdentity(stat); !errors.Is(err, ErrSQLiteJournalUnsupported) {
+		t.Fatalf("birth-time error = %v, want unsupported", err)
+	}
+	stat.Mask = unix.STATX_BTIME
+	if _, err := sqliteJournalIdentity(stat); !errors.Is(err, ErrSQLiteJournalUnsupported) {
+		t.Fatalf("mount-ID error = %v, want unsupported", err)
+	}
+}
+
+func TestSQLiteJournalWatch_RejectsInvalidLifecycleEvents(t *testing.T) {
+	for name, mask := range map[string]uint32{
+		"overflow":      unix.IN_Q_OVERFLOW,
+		"move self":     unix.IN_MOVE_SELF,
+		"unmount":       unix.IN_UNMOUNT,
+		"ignored":       unix.IN_IGNORED,
+		"missing close": unix.IN_DELETE_SELF,
+	} {
+		t.Run(name, func(t *testing.T) {
+			// Given
+			watch := &SQLiteJournalWatch{}
+			// When
+			err := watch.observe(mask)
+
+			// Then
+			if err == nil {
+				t.Fatal("invalid lifecycle event was accepted")
+			}
+		})
+	}
+}
+
+func TestSQLiteJournalWatch_RejectsDuplicateTerminalEvent(t *testing.T) {
+	// Given
+	watch := &SQLiteJournalWatch{}
+	requireNoError(t, watch.observe(unix.IN_CLOSE_WRITE))
+	requireNoError(t, watch.observe(unix.IN_DELETE_SELF))
+
+	// When
+	err := watch.observe(unix.IN_DELETE_SELF)
+
+	// Then
+	if !errors.Is(err, ErrSQLiteJournalLifecycle) {
+		t.Fatalf("duplicate terminal error = %v, want lifecycle error", err)
+	}
+}
+
+func TestSQLiteJournalWatch_WaitsForCloseThenDeleteAndCancellation(t *testing.T) {
+	// Given
+	path := writeJournal(t, "dashboard.sqlite-journal")
+	watch, err := OpenSQLiteJournalWatch(path)
+	requireNoError(t, err)
+	t.Cleanup(func() { requireNoError(t, watch.Close()) })
+	ctx, cancel := context.WithCancel(t.Context())
+	result := make(chan error, 1)
+	go func() { result <- watch.Wait(ctx) }()
+
+	// When
+	cancel()
+	err = <-result
+
+	// Then
+	if !errors.Is(err, context.Canceled) {
+		t.Fatalf("wait error = %v, want cancellation", err)
+	}
+	if err := watch.observe(unix.IN_CLOSE_WRITE); err != nil {
+		t.Fatalf("close write: %v", err)
+	}
+	if err := watch.observe(unix.IN_DELETE_SELF); err != nil {
+		t.Fatalf("delete self: %v", err)
+	}
+}
+
+func TestSQLiteJournalWatch_WaitsForExactCloseDeleteLifecycle(t *testing.T) {
+	// Given
+	path := writeJournal(t, "dashboard.sqlite-journal")
+	watch, err := OpenSQLiteJournalWatch(path)
+	requireNoError(t, err)
+	t.Cleanup(func() { requireNoError(t, watch.Close()) })
+	result := make(chan error, 1)
+	go func() { result <- watch.Wait(t.Context()) }()
+	journal, err := os.OpenFile(path, os.O_WRONLY|os.O_APPEND, 0)
+	requireNoError(t, err)
+	requireNoError(t, journal.Close())
+	requireNoError(t, os.Remove(path))
+
+	// When
+	err = <-result
+
+	// Then
+	requireNoError(t, err)
+}
+
+func writeJournal(t *testing.T, name string) string {
+	t.Helper()
+	path := filepath.Join(t.TempDir(), name)
+	requireNoError(t, os.WriteFile(path, []byte("journal"), 0o600))
+	return path
+}