Log changed files after backup

internal/restic/restic_test.go

@@ -190,6 +190,49 @@ func TestRestoreReportsProgress(t *testing.T) {
 	}
 }
 
+func TestDiffReportsLastChangedPaths(t *testing.T) {
+	dir := t.TempDir()
+	argsPath := filepath.Join(dir, "args")
+	script := filepath.Join(dir, "restic")
+	body := fmt.Sprintf(`#!/bin/sh
+printf '%%s\n' "$@" > '%s'
+printf '%%s\n' 'comparing snapshot before to after:'
+printf '%%s\n' '+    /mnt/user/new.txt'
+printf '%%s\n' 'M    /mnt/user/modified-a.txt'
+printf '%%s\n' '-    /mnt/user/removed.txt'
+printf '%%s\n' 'M    /mnt/user/modified-b.txt'
+printf '%%s\n' 'Files: 1 new, 1 removed, 2 changed'
+`, argsPath)
+	if err := os.WriteFile(script, []byte(body), 0700); err != nil {
+		t.Fatal(err)
+	}
+	runner := &Runner{Binary: script, RuntimeDir: dir, Secrets: fakeSecrets{"password": "secret"}}
+	repo := model.Repository{Type: model.RepositoryLocal, Location: "/repo", PasswordRef: "password"}
+	diff, err := runner.Diff(context.Background(), repo, "before", "after", 3)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if diff.Total != 4 || len(diff.Entries) != 3 {
+		t.Fatalf("unexpected diff result: %+v", diff)
+	}
+	expected := []DiffEntry{
+		{Kind: "modified", Path: "/mnt/user/modified-a.txt"},
+		{Kind: "removed", Path: "/mnt/user/removed.txt"},
+		{Kind: "modified", Path: "/mnt/user/modified-b.txt"},
+	}
+	for index, entry := range expected {
+		if diff.Entries[index] != entry {
+			t.Fatalf("entry %d = %+v, want %+v", index, diff.Entries[index], entry)
+		}
+	}
+	args, _ := os.ReadFile(argsPath)
+	for _, expected := range []string{"diff", "--metadata", "before", "after"} {
+		if !strings.Contains(string(args), expected) {
+			t.Fatalf("arguments missing %q: %s", expected, args)
+		}
+	}
+}
+
 func TestStatsUsesRequestedRepositoryCountingMode(t *testing.T) {
 	dir := t.TempDir()
 	argsPath := filepath.Join(dir, "args")