1 files changed, 263 insertions, 0 deletions
diff --git a/internal/scan/scan_test.go b/internal/scan/scan_test.go
new file mode 100644
index 0000000..94f922b
--- /dev/null
+++ b/internal/scan/scan_test.go
@@ -0,0 +1,263 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+package scan
+
+import (
+	"errors"
+	"fmt"
+	"io/fs"
+	"os"
+	"path/filepath"
+	"reflect"
+	"syscall"
+	"testing"
+	"time"
+
+	"krino/internal/ignore"
+)
+
+var now = time.Date(2026, 9, 11, 12, 0, 0, 0, time.UTC)
+
+// tree creates files (with an mtime one hour before now) and returns the root.
+func tree(t *testing.T, files ...string) string {
+	t.Helper()
+	root := t.TempDir()
+	for _, f := range files {
+		p := filepath.Join(root, f)
+		if err := os.MkdirAll(filepath.Dir(p), 0o755); err != nil {
+			t.Fatal(err)
+		}
+		if err := os.WriteFile(p, []byte(f), 0o644); err != nil {
+			t.Fatal(err)
+		}
+		old := now.Add(-time.Hour)
+		if err := os.Chtimes(p, old, old); err != nil {
+			t.Fatal(err)
+		}
+	}
+	return root
+}
+
+func rels(r *Result) []string {
+	var out []string
+	for _, f := range r.Files {
+		out = append(out, f.Rel)
+	}
+	return out
+}
+
+func skipped(r *Result) map[string]Reason {
+	m := map[string]Reason{}
+	for _, s := range r.Skipped {
+		m[s.Rel] = s.Reason
+	}
+	return m
+}
+
+func TestTopLevelOnly(t *testing.T) {
+	root := tree(t, "a.pdf", "b.txt", "sub/c.txt")
+	r, err := Walk(root, Options{Now: now})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if want := []string{"a.pdf", "b.txt"}; !reflect.DeepEqual(rels(r), want) {
+		t.Fatalf("files = %v, want %v", rels(r), want)
+	}
+	f := r.Files[0]
+	if f.Name != "a.pdf" || f.Size != int64(len("a.pdf")) || f.Path != filepath.Join(root, "a.pdf") || !f.ModTime.Equal(now.Add(-time.Hour)) {
+		t.Fatalf("file = %+v", f)
+	}
+}
+
+func TestRecursiveDepthExcludeIgnore(t *testing.T) {
+	root := tree(t, "a.txt", "one/b.txt", "one/two/c.txt", "Work/filed.pdf", "skip/x.txt", "keep/y.log")
+	m, _ := ignore.New([]string{"skip/", "*.log"})
+	r, err := Walk(root, Options{Recursive: true, Ignore: m, Exclude: []string{filepath.Join(root, "Work")}, Now: now})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if want := []string{"a.txt", "one/b.txt", "one/two/c.txt"}; !reflect.DeepEqual(rels(r), want) {
+		t.Fatalf("files = %v, want %v", rels(r), want)
+	}
+	if got := skipped(r); got["keep/y.log"] != Ignored {
+		t.Fatalf("skipped = %v", got)
+	}
+	r, _ = Walk(root, Options{Recursive: true, MaxDepth: 2, Now: now})
+	for _, rel := range rels(r) {
+		if rel == "one/two/c.txt" {
+			t.Fatalf("MaxDepth 2 reached depth 3: %v", rels(r))
+		}
+	}
+}
+
+func TestBusyTooNewSymlinkFifo(t *testing.T) {
+	root := tree(t, "movie.mkv", "movie.mkv.aria2", "doc.pdf", "doc.pdf.part", "plain.txt")
+	fresh := filepath.Join(root, "fresh.txt")
+	if err := os.WriteFile(fresh, nil, 0o644); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.Chtimes(fresh, now.Add(-30*time.Second), now.Add(-30*time.Second)); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.Symlink(filepath.Join(root, "plain.txt"), filepath.Join(root, "link.txt")); err != nil {
+		t.Fatal(err)
+	}
+	fifo := filepath.Join(root, "pipe")
+	haveFifo := syscall.Mkfifo(fifo, 0o644) == nil
+	m, _ := ignore.New([]string{"*.part", "*.aria2"})
+	r, err := Walk(root, Options{Ignore: m, Busy: []string{".part", ".aria2"}, MinAge: 2 * time.Minute, Now: now})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if want := []string{"plain.txt"}; !reflect.DeepEqual(rels(r), want) {
+		t.Fatalf("files = %v, want %v", rels(r), want)
+	}
+	want := map[string]Reason{
+		"movie.mkv": Busy, "doc.pdf": Busy, "movie.mkv.aria2": Ignored, "doc.pdf.part": Ignored,
+		"fresh.txt": TooNew, "link.txt": Symlink,
+	}
+	if haveFifo {
+		want["pipe"] = NotRegular
+	}
+	if got := skipped(r); !reflect.DeepEqual(got, want) {
+		t.Fatalf("skipped = %v, want %v", got, want)
+	}
+}
+
+func TestSymlinkedDirNotFollowed(t *testing.T) {
+	root := tree(t, "real/x.txt")
+	if err := os.Symlink(filepath.Join(root, "real"), filepath.Join(root, "alias")); err != nil {
+		t.Fatal(err)
+	}
+	r, err := Walk(root, Options{Recursive: true, Now: now})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if want := []string{"real/x.txt"}; !reflect.DeepEqual(rels(r), want) {
+		t.Fatalf("files = %v, want %v", rels(r), want)
+	}
+	if skipped(r)["alias"] != Symlink {
+		t.Fatalf("skipped = %v", skipped(r))
+	}
+}
+
+func TestReasonString(t *testing.T) {
+	want := map[Reason]string{Ignored: "ignored", Busy: "busy", TooNew: "too new", Symlink: "symlink", NotRegular: "not a regular file", Unreadable: "unreadable"}
+	for r, s := range want {
+		if r.String() != s {
+			t.Errorf("%d = %q, want %q", r, r.String(), s)
+		}
+	}
+}
+
+func TestUnreadableSubdir(t *testing.T) {
+	if os.Geteuid() == 0 {
+		t.Skip("running as root: permissions are not enforced")
+	}
+	root := tree(t, "a.txt", "locked/secret.txt", "one/b.txt")
+	locked := filepath.Join(root, "locked")
+	if err := os.Chmod(locked, 0o000); err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(func() {
+		if err := os.Chmod(locked, 0o755); err != nil {
+			t.Fatal(err)
+		}
+	})
+	r, err := Walk(root, Options{Recursive: true, Now: now})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if want := []string{"a.txt", "one/b.txt"}; !reflect.DeepEqual(rels(r), want) {
+		t.Fatalf("files = %v, want %v", rels(r), want)
+	}
+	if got := skipped(r)["locked"]; got != Unreadable {
+		t.Fatalf("skipped[locked] = %v, want Unreadable", got)
+	}
+}
+
+func TestRootMustBeDirectory(t *testing.T) {
+	root := tree(t, "f")
+	if _, err := Walk(filepath.Join(root, "f"), Options{Now: now}); err == nil {
+		t.Fatal("walking a file succeeded")
+	}
+	if _, err := Walk(filepath.Join(root, "missing"), Options{Now: now}); err == nil {
+		t.Fatal("walking a missing path succeeded")
+	}
+}
+
+// fakeDirEntry is an os.DirEntry whose Info() returns a canned result,
+// simulating a race scan_test cannot otherwise provoke portably: a file
+// renamed or removed between being listed by ReadDir and having Info()
+// called on it (A2), or some other Info() failure.
+type fakeDirEntry struct {
+	name    string
+	info    fs.FileInfo
+	infoErr error
+}
+
+func (f fakeDirEntry) Name() string               { return f.name }
+func (f fakeDirEntry) IsDir() bool                { return false }
+func (f fakeDirEntry) Type() fs.FileMode          { return 0 }
+func (f fakeDirEntry) Info() (fs.FileInfo, error) { return f.info, f.infoErr }
+
+// TestFileInfoFailureMidWalk: A2. A vanished file's Info() failure
+// (fs.ErrNotExist) is skipped silently, with no trace in Skipped; any
+// other Info() failure is reported as Unreadable; and the walk continues
+// to later entries in either case rather than aborting.
+func TestFileInfoFailureMidWalk(t *testing.T) {
+	root := t.TempDir()
+	okPath := filepath.Join(root, "ok.txt")
+	if err := os.WriteFile(okPath, []byte("ok"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+	old := now.Add(-time.Hour)
+	if err := os.Chtimes(okPath, old, old); err != nil {
+		t.Fatal(err)
+	}
+	okInfo, err := os.Lstat(okPath)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	entries := []os.DirEntry{
+		fakeDirEntry{name: "vanished.txt", infoErr: fmt.Errorf("stat vanished.txt: %w", fs.ErrNotExist)},
+		fakeDirEntry{name: "denied.txt", infoErr: errors.New("stat denied.txt: permission denied")},
+		fakeDirEntry{name: "ok.txt", info: okInfo},
+	}
+
+	w := &walker{root: root, opt: Options{Now: now}}
+	if err := w.walk(root, "", 1, entries); err != nil {
+		t.Fatalf("walk aborted: %v", err)
+	}
+
+	if want := []string{"ok.txt"}; !reflect.DeepEqual(rels(&w.result), want) {
+		t.Fatalf("files = %v, want %v", rels(&w.result), want)
+	}
+	got := skipped(&w.result)
+	if _, vanished := got["vanished.txt"]; vanished {
+		t.Errorf("vanished file recorded as skipped: %v", got)
+	}
+	if got["denied.txt"] != Unreadable {
+		t.Errorf("skipped[denied.txt] = %v, want Unreadable", got["denied.txt"])
+	}
+}
+
+// TestIgnoredDirectoryReportedOnce: C2. An ignored directory with files
+// inside it is reported once, for the directory itself, not once per file
+// — pruning it without descending is the point — so its contents are not
+// simply invisible to every count and to -v.
+func TestIgnoredDirectoryReportedOnce(t *testing.T) {
+	root := tree(t, "keep.txt", "skip/a.txt", "skip/b.txt", "skip/c.txt")
+	m, _ := ignore.New([]string{"skip/"})
+	r, err := Walk(root, Options{Recursive: true, Ignore: m, Now: now})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if want := []string{"keep.txt"}; !reflect.DeepEqual(rels(r), want) {
+		t.Fatalf("files = %v, want %v", rels(r), want)
+	}
+	if want := (map[string]Reason{"skip": Ignored}); !reflect.DeepEqual(skipped(r), want) {
+		t.Fatalf("skipped = %v, want %v (the directory once, not its three files)", skipped(r), want)
+	}
+}