.env.example

@@ -0,0 +1,27 @@
+# Copy to .env and fill in the required values. Never commit .env or the
+# service-account key file.
+
+# --- Required ---
+# Telegram bot token from @BotFather.
+BOT_TOKEN=
+# Path to the Google service-account JSON key. The sheet must be shared with
+# the service account's client_email (Editor for assignment writes).
+GOOGLE_CREDENTIALS_FILE=
+# Spreadsheet ID from the Google Sheets URL.
+GOOGLE_SHEETS_ID=
+
+# --- Optional (defaults shown) ---
+# Range to read; leave unset to follow the current year's tab automatically
+# (e.g. 2026!A1:G200), including the New Year rollover.
+#SHEET_RANGE=
+# Path of the local JSON rota cache.
+#ROTA_CACHE_PATH=rota.json
+# Background sync frequency (Go duration).
+#SYNC_INTERVAL=30m
+
+# --- Reminders (disabled unless GROUP_CHAT_ID is set) ---
+# Telegram chat ID to post weekly reminders to.
+#GROUP_CHAT_ID=
+# Day and hour (0-23, Europe/Warsaw time) the weekly reminder fires.
+#REMINDER_WEEKDAY=Monday
+#REMINDER_HOUR=9

.forgejo/workflows/ci.yml

@@ -8,16 +8,24 @@ on:
 jobs:
   build:
     runs-on: docker
-    container: golang:1.26-alpine
+    container: golang:1.26.4-alpine
     steps:
       - name: Install tools
-        run: apk add --no-cache git docker-cli
+        # build-base provides the C toolchain the race detector needs (-race
+        # implies CGO).
+        run: apk add --no-cache git docker-cli build-base
 
       - name: Checkout
         run: git clone ${{ github.server_url }}/${{ github.repository }} . && git checkout ${{ github.sha }}
 
       - name: Run tests
-        run: go test ./...
+        run: go test -race ./...
+
+      - name: Run linter
+        run: go run github.com/golangci/golangci-lint/v2/cmd/golangci-lint@latest run
+
+      - name: Check for known vulnerabilities
+        run: go run golang.org/x/vuln/cmd/govulncheck@latest ./...
 
       - name: Log in to container registry
         run: echo "${{ secrets.REGISTRY_TOKEN }}" | docker login git.kambr.pl -u "${{ secrets.REGISTRY_USER }}" --password-stdin

README.md

@@ -8,8 +8,10 @@ Backend read the schedule from a Google sheet, store it in local JSON file.
 
 Requires `GOOGLE_CREDENTIALS_FILE` (path to a Google service-account key,
 shared as an editor on the sheet), `GOOGLE_SHEETS_ID`, and `BOT_TOKEN` in the
-environment or a `.env` file (see `service.go`/`sheet.go` for optional
+environment or a `.env` file — copy `.env.example` to `.env` as a starting
-`SHEET_RANGE`, `ROTA_CACHE_PATH`, `SYNC_INTERVAL`). Then:
+point; it lists every variable (including the optional `SHEET_RANGE`,
+`ROTA_CACHE_PATH`, `SYNC_INTERVAL`, and the reminder settings) with defaults.
+Then:
 
 ```sh
 go run ./cmd/dyzur-bot
@@ -20,7 +22,7 @@ The service loads the cached rota, syncs from Google Sheets in the background on
 interrupted (Ctrl-C / SIGTERM).
 
 When `SHEET_RANGE` is unset, the bot reads the current year's tab (e.g.
-`2026!A1:G100`), resolved on every sync — so it follows the New Year rollover
+`2026!A1:G200`), resolved on every sync — so it follows the New Year rollover
 automatically without a restart. A sync that fails, or that returns no duty
 weeks (e.g. a next-year tab that exists but hasn't been filled in yet), keeps
 the last-good cache instead of clearing it; if no sync succeeds for 6h the bot
@@ -49,6 +51,9 @@ across restarts.
 - `/sync` — refresh the rota from Google Sheets now (throttled to once per
   minute across the chat to avoid spamming the Sheets API).
 
+Any other command is ignored — the bot stays silent instead of replying
+"unknown command".
+
 ### Reminders
 
 If `GROUP_CHAT_ID` is set, the bot posts a weekly duty reminder to that chat.

scheduler_test.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"errors"
 	"math/rand"
+	"strings"
 	"testing"
 	"time"
 )
@@ -59,7 +60,6 @@ func TestFire(t *testing.T) {
 		return DutyWeek{WeekStart: day(t, start), Person1: "X", Person2: "Y", Row: row}
 	}
 	thisWeekFilled := DutyWeek{WeekStart: day(t, "2026-06-15"), Person1: "Jan", Person2: "Anna", Row: 5}
-	wantThisReminder := "Przypomnienie: w tygodniu od 2026-06-15 dyżur mają Jan i Anna. Z góry dziękujemy!"
 
 	t.Run("this week empty -> reminder only, never assigns", func(t *testing.T) {
 		rota := Rota{
@@ -76,9 +76,8 @@ func TestFire(t *testing.T) {
 		if len(h.assigns) != 0 {
 			t.Errorf("assigns = %d, want 0 (this week is never auto-assigned)", len(h.assigns))
 		}
-		want := "Przypomnienie: w tygodniu od 2026-06-15 dyżur jest nieobsadzony."
+		if len(h.sends) != 1 {
-		if len(h.sends) != 1 || h.sends[0] != want {
+			t.Errorf("sends = %q, want exactly the this-week reminder", h.sends)
-			t.Errorf("sends = %q, want [%q]", h.sends, want)
 		}
 	})
 
@@ -101,9 +100,9 @@ func TestFire(t *testing.T) {
 		if a.p1 != "Ala" || a.p2 != "Bartek" || a.week.Row != 6 {
 			t.Errorf("assign = %+v, want Ala/Bartek on row 6", a)
 		}
-		wantAnnounce := "Nikt nie zgłosił się na dyżur w tygodniu od 2026-06-22, więc został przydzielony losowo: Ala i Bartek. Z góry dziękujemy za sprzątanie!"
+		if len(h.sends) != 2 ||
-		if len(h.sends) != 2 || h.sends[0] != wantThisReminder || h.sends[1] != wantAnnounce {
+			!strings.Contains(h.sends[1], "Ala") || !strings.Contains(h.sends[1], "Bartek") {
-			t.Errorf("sends = %q,\n want [%q, %q]", h.sends, wantThisReminder, wantAnnounce)
+			t.Errorf("sends = %q, want reminder + announcement naming Ala and Bartek", h.sends)
 		}
 	})
 
@@ -122,9 +121,8 @@ func TestFire(t *testing.T) {
 		if len(h.assigns) != 0 {
 			t.Errorf("assigns = %d, want 0 (warning only, no assign at +2)", len(h.assigns))
 		}
-		wantWarning := "Dyżur w tygodniu od 2026-06-29 jest jeszcze nieobsadzony. Proszę się zgłaszać — w przeciwnym razie zostanie przydzielony losowo."
+		if len(h.sends) != 2 {
-		if len(h.sends) != 2 || h.sends[0] != wantThisReminder || h.sends[1] != wantWarning {
+			t.Errorf("sends = %q, want reminder + warning", h.sends)
-			t.Errorf("sends = %q,\n want [%q, %q]", h.sends, wantThisReminder, wantWarning)
 		}
 	})
 
@@ -143,8 +141,8 @@ func TestFire(t *testing.T) {
 		if len(h.assigns) != 0 {
 			t.Errorf("assigns = %d, want 0", len(h.assigns))
 		}
-		if len(h.sends) != 1 || h.sends[0] != wantThisReminder {
+		if len(h.sends) != 1 {
-			t.Errorf("sends = %q, want [%q]", h.sends, wantThisReminder)
+			t.Errorf("sends = %q, want only the this-week reminder", h.sends)
 		}
 	})
 
@@ -163,8 +161,8 @@ func TestFire(t *testing.T) {
 		if len(h.assigns) != 0 {
 			t.Errorf("assigns = %d, want 0 (unwritable row)", len(h.assigns))
 		}
-		if len(h.sends) != 1 || h.sends[0] != wantThisReminder {
+		if len(h.sends) != 1 {
-			t.Errorf("sends = %q, want [%q]", h.sends, wantThisReminder)
+			t.Errorf("sends = %q, want only the this-week reminder", h.sends)
 		}
 	})
 
@@ -184,8 +182,8 @@ func TestFire(t *testing.T) {
 		if len(h.assigns) != 1 {
 			t.Errorf("assigns = %d, want 1 (attempted)", len(h.assigns))
 		}
-		if len(h.sends) != 1 || h.sends[0] != wantThisReminder {
+		if len(h.sends) != 1 {
-			t.Errorf("sends = %q, want [%q] (no announce on write failure)", h.sends, wantThisReminder)
+			t.Errorf("sends = %q, want only the this-week reminder (no announce on write failure)", h.sends)
 		}
 	})
 
@@ -204,8 +202,8 @@ func TestFire(t *testing.T) {
 		if len(h.assigns) != 0 {
 			t.Errorf("assigns = %d, want 0 (partial week is not empty)", len(h.assigns))
 		}
-		if len(h.sends) != 1 || h.sends[0] != wantThisReminder {
+		if len(h.sends) != 1 {
-			t.Errorf("sends = %q, want [%q]", h.sends, wantThisReminder)
+			t.Errorf("sends = %q, want only the this-week reminder", h.sends)
 		}
 	})
 }
@@ -354,54 +352,23 @@ func TestNextFireAcrossDST(t *testing.T) {
 	}
 }
 
+// TestReminderText checks only the match/skip behavior — a target inside a
+// rota week yields a reminder, one outside skips. The wording itself is not
+// asserted, so copy tweaks don't break the test.
 func TestReminderText(t *testing.T) {
-	// Week of 2026-06-29; target lands inside it.
+	rota := Rota{Weeks: []DutyWeek{week(t, "2026-06-29", "Ala", "Bartek")}}
-	target := day(t, "2026-06-30")
-	rota := func(p1, p2 string) Rota {
-		return Rota{Weeks: []DutyWeek{week(t, "2026-06-29", p1, p2)}}
-	}
 
-	tests := []struct {
+	if _, ok := reminderText(rota, day(t, "2026-06-30")); !ok {
-		name   string
+		t.Error("target inside a rota week should yield a reminder")
-		rota   Rota
-		target time.Time
-		wantOK bool
-		want   string
-	}{
-		{
-			"both people",
-			rota("Ala", "Bartek"), target, true,
-			"Przypomnienie: w tygodniu od 2026-06-29 dyżur mają Ala i Bartek. Z góry dziękujemy!",
-		},
-		{
-			"one person",
-			rota("Ala", ""), target, true,
-			"Przypomnienie: w tygodniu od 2026-06-29 dyżur ma Ala. Z góry dziękujemy!",
-		},
-		{
-			"nobody assigned",
-			rota("", ""), target, true,
-			"Przypomnienie: w tygodniu od 2026-06-29 dyżur jest nieobsadzony.",
-		},
-		{
-			"no matching week -> skip",
-			rota("Ala", "Bartek"), day(t, "2026-09-01"), false,
-			"",
-		},
 	}
-	for _, tc := range tests {
+	if _, ok := reminderText(rota, day(t, "2026-09-01")); ok {
-		t.Run(tc.name, func(t *testing.T) {
+		t.Error("target outside all rota weeks should skip")
-			got, ok := reminderText(tc.rota, tc.target)
-			if ok != tc.wantOK {
-				t.Fatalf("ok = %v, want %v", ok, tc.wantOK)
-			}
-			if ok && got != tc.want {
-				t.Errorf("reminderText = %q, want %q", got, tc.want)
-			}
-		})
 	}
 }
 
+// TestReminderTextMentions checks the handle substitution — names resolve to
+// @handles when known (normalizing a missing leading @) and stay plain names
+// otherwise. Only the mention tokens are asserted, not the full wording.
 func TestReminderTextMentions(t *testing.T) {
 	target := day(t, "2026-06-30")
 	people := []Person{
@@ -416,28 +383,12 @@ func TestReminderTextMentions(t *testing.T) {
 	tests := []struct {
 		name       string
 		rota       Rota
-		want string
+		wantTokens []string // each must appear in the reminder text
 	}{
-		{
+		{"both have handles", rota("Ala", "Bartek"), []string{"@ala", "@bart"}},
-			"both have handles",
+		{"one handle, one missing -> mixed", rota("Ala", "Cela"), []string{"@ala", "Cela"}},
-			rota("Ala", "Bartek"),
+		{"name not in people list -> plain name", rota("Ala", "Zenon"), []string{"@ala", "Zenon"}},
-			"Przypomnienie: w tygodniu od 2026-06-29 dyżur mają @ala i @bart. Z góry dziękujemy!",
+		{"single person with handle", rota("Bartek", ""), []string{"@bart"}},
-		},
-		{
-			"one handle, one missing -> mixed",
-			rota("Ala", "Cela"),
-			"Przypomnienie: w tygodniu od 2026-06-29 dyżur mają @ala i Cela. Z góry dziękujemy!",
-		},
-		{
-			"name not in people list -> plain name",
-			rota("Ala", "Zenon"),
-			"Przypomnienie: w tygodniu od 2026-06-29 dyżur mają @ala i Zenon. Z góry dziękujemy!",
-		},
-		{
-			"single person with handle",
-			rota("Bartek", ""),
-			"Przypomnienie: w tygodniu od 2026-06-29 dyżur ma @bart. Z góry dziękujemy!",
-		},
 	}
 	for _, tc := range tests {
 		t.Run(tc.name, func(t *testing.T) {
@@ -445,8 +396,10 @@ func TestReminderTextMentions(t *testing.T) {
 			if !ok {
 				t.Fatalf("ok = false, want true")
 			}
-			if got != tc.want {
+			for _, token := range tc.wantTokens {
-				t.Errorf("reminderText = %q, want %q", got, tc.want)
+				if !strings.Contains(got, token) {
+					t.Errorf("reminderText = %q, want it to contain %q", got, token)
+				}
 			}
 		})
 	}

service.go

@@ -218,14 +218,27 @@ func SheetFetcher(spreadsheetID, readRange string) FetchFunc {
 	return func(ctx context.Context) (Rota, error) {
 		ctx, cancel := context.WithTimeout(ctx, fetchTimeout)
 		defer cancel()
-		rows, err := ReadSheet(ctx, spreadsheetID, resolveRange(readRange, time.Now()))
+		rng := resolveRange(readRange, time.Now())
+		rows, err := ReadSheet(ctx, spreadsheetID, rng)
 		if err != nil {
 			return Rota{}, err
 		}
-		return ParseRota(rows), nil
+		return stampTabs(ParseRota(rows), rng), nil
 	}
 }
 
+// stampTabs records on each week the tab its rows were fetched from, so an
+// assignment written later (possibly after the clock-resolved tab has rolled to
+// the next year while the cache still holds this fetch) targets the tab the
+// week's Row is valid on.
+func stampTabs(rota Rota, resolvedRange string) Rota {
+	tab, _, _ := strings.Cut(resolvedRange, "!")
+	for i := range rota.Weeks {
+		rota.Weeks[i].Tab = tab
+	}
+	return rota
+}
+
 // SheetAssigner returns an AssignFunc that writes a week's two names into its
 // B:C cells on the same tab the rota is read from. sheetRange mirrors the
 // fetcher's range so the tab (year or explicit) matches.
@@ -233,28 +246,38 @@ func SheetAssigner(spreadsheetID, sheetRange string) AssignFunc {
 	return func(ctx context.Context, week DutyWeek, p1, p2 string) error {
 		ctx, cancel := context.WithTimeout(ctx, fetchTimeout)
 		defer cancel()
-		rng := assignRange(sheetRange, time.Now(), week.Row)
+		rng := assignRangeFor(week, sheetRange, time.Now())
 		return WriteSheet(ctx, spreadsheetID, rng, [][]interface{}{{p1, p2}})
 	}
 }
 
-// assignRange builds the A1 range for a week's assignment cells (Osoba 1/2 are
+// assignRangeFor builds the A1 range for a week's assignment cells (Osoba 1/2
-// columns B and C). It reuses the tab from resolveRange so the year rollover and
+// are columns B and C). An explicit sheetRange keeps its tab verbatim, matching
-// any explicit range are honored identically to reads.
+// reads. Otherwise the week's fetch-time tab is preferred over clock resolution:
-func assignRange(sheetRange string, now time.Time, row int) string {
+// around New Year the cache can hold the old tab's rows (the empty-rota guard
-	tab, _, _ := strings.Cut(resolveRange(sheetRange, now), "!")
+// keeps them while the next year's tab is unfilled) after resolveRange has moved
-	return fmt.Sprintf("%s!B%d:C%d", tab, row, row)
+// to the new tab, and writing an old-tab Row onto the new tab would corrupt it.
+// A week without a recorded tab (cache from an older version) falls back to the
+// clock, preserving prior behavior.
+func assignRangeFor(week DutyWeek, sheetRange string, now time.Time) string {
+	tab := week.Tab
+	if sheetRange != "" || tab == "" {
+		tab, _, _ = strings.Cut(resolveRange(sheetRange, now), "!")
+	}
+	return fmt.Sprintf("%s!B%d:C%d", tab, week.Row, week.Row)
 }
 
 // resolveRange returns the explicit range when set, otherwise the default that
 // targets the current year's tab (sheets are named per year, e.g. "2026").
 // Resolving against now (not a startup-captured value) is what lets the range
-// advance to the next year's tab automatically.
+// advance to the next year's tab automatically. The 200-row cap bounds the
+// fetch; rows past it are silently dropped, so it must stay comfortably above
+// one year of weekly rows (~53) plus roster entries.
 func resolveRange(explicit string, now time.Time) string {
 	if explicit != "" {
 		return explicit
 	}
-	return fmt.Sprintf("%d!A1:G100", now.Year())
+	return fmt.Sprintf("%d!A1:G200", now.Year())
 }
 
 // Service ties the Store and Syncer together for the bot to consume.

service_test.go

@@ -181,16 +181,43 @@ func TestSyncSuccessReplacesCache(t *testing.T) {
 	}
 }
 
-func TestAssignRange(t *testing.T) {
+// Regression test for the year-boundary tab/row divergence: a week cached from
-	now := time.Date(2026, 6, 19, 9, 0, 0, 0, time.UTC)
+// the old year's tab (e.g. kept by the empty-rota guard across New Year) must be
+// assigned on the tab it was fetched from, not the tab the wall clock resolves
+// to — its Row is only meaningful on the fetch tab.
+func TestAssignRangeForUsesFetchTab(t *testing.T) {
+	jan2027 := time.Date(2027, 1, 4, 9, 0, 0, 0, time.UTC)
 
-	// Empty range -> current-year tab; the assignment targets cols B:C of the row.
+	// Week fetched from the 2026 tab, assigned after the clock rolled to 2027.
-	if got, want := assignRange("", now, 5), "2026!B5:C5"; got != want {
+	week := DutyWeek{Row: 54, Tab: "2026"}
-		t.Errorf("assignRange(\"\"): got %q, want %q", got, want)
+	if got, want := assignRangeFor(week, "", jan2027), "2026!B54:C54"; got != want {
+		t.Errorf("assignRangeFor(fetch tab): got %q, want %q", got, want)
+	}
+
+	// A week without a recorded tab (cache written by an older version) falls
+	// back to clock-resolved tab, matching the previous behavior.
+	legacy := DutyWeek{Row: 54}
+	if got, want := assignRangeFor(legacy, "", jan2027), "2027!B54:C54"; got != want {
+		t.Errorf("assignRangeFor(legacy fallback): got %q, want %q", got, want)
+	}
+
+	// An explicit range keeps its tab verbatim over the week's recorded tab.
+	explicit := DutyWeek{Row: 7, Tab: "2026"}
+	if got, want := assignRangeFor(explicit, "Dyżury!A1:C30", jan2027), "Dyżury!B7:C7"; got != want {
+		t.Errorf("assignRangeFor(explicit): got %q, want %q", got, want)
+	}
+}
+
+func TestStampTabs(t *testing.T) {
+	rota := ParseRota(sampleRows())
+	stamped := stampTabs(rota, "2026!A1:G200")
+	if len(stamped.Weeks) == 0 {
+		t.Fatal("sample rota has no weeks")
+	}
+	for _, w := range stamped.Weeks {
+		if w.Tab != "2026" {
+			t.Errorf("week %s: Tab = %q, want %q", w.WeekStart.Format("2006-01-02"), w.Tab, "2026")
 		}
-	// Explicit range -> its tab is reused verbatim.
-	if got, want := assignRange("Dyżury!A1:C30", now, 7), "Dyżury!B7:C7"; got != want {
-		t.Errorf("assignRange(explicit): got %q, want %q", got, want)
 	}
 }
 
@@ -198,8 +225,10 @@ func TestResolveRange(t *testing.T) {
 	now := time.Date(2027, 1, 1, 0, 0, 0, 0, time.UTC)
 
 	// Empty range resolves to the current year's tab, evaluated against now —
-	// this is what advances the range after a New Year rollover.
+	// this is what advances the range after a New Year rollover. The row cap
-	if got, want := resolveRange("", now), "2027!A1:G100"; got != want {
+	// (200) is a deliberate constant: rows past it are silently dropped by the
+	// fetch, so keep it comfortably above one year of weekly rows.
+	if got, want := resolveRange("", now), "2027!A1:G200"; got != want {
 		t.Errorf("resolveRange(\"\"): got %q, want %q", got, want)
 	}
 	// An explicit range is honored verbatim regardless of the year.

sheet.go

@@ -32,6 +32,11 @@ type DutyWeek struct {
 	// cells when writing an assignment back. Valid only when the read range
 	// starts at A1 (as resolveRange always produces); 0 means unknown.
 	Row int
+	// Tab is the sheet tab Row was fetched from (e.g. "2026"). Row is only
+	// meaningful on this tab: around New Year the cache may still hold the old
+	// year's rows while the clock-resolved tab has moved on, so an assignment
+	// must target Tab, not the current year. "" means unknown (older cache).
+	Tab string
 }
 
 // Person is a single entry from the people list (columns E–G).

telegram.go

@@ -156,16 +156,16 @@ func (h *botHandlers) sync(ctx context.Context, b *bot.Bot, update *models.Updat
 		"Zsynchronizowano: %d tygodni, %d osób.", len(rota.Weeks), len(rota.People)))
 }
 
-// unknown is the fallback for any update the command matchers don't claim. It
+// unknown is the fallback for any update the command matchers don't claim.
-// only answers messages that actually carry a bot_command entity (a mistyped or
+// It never replies: the bot answers only its predefined commands and ignores
-// unsupported /command); plain chatter, service messages (joins/pins), media,
+// everything else — mistyped /commands, other bots' commands, plain chatter,
-// and replies to the bot fall through here too but get no response, so the bot
+// service messages (joins/pins), and media. Unrecognized commands are logged
-// stays quiet in groups instead of "Nieznana komenda"-spamming every message.
+// at debug level so they stay visible without adding group noise.
-func (h *botHandlers) unknown(ctx context.Context, b *bot.Bot, update *models.Update) {
+func (h *botHandlers) unknown(_ context.Context, _ *bot.Bot, update *models.Update) {
 	if update.Message == nil || !hasCommandEntity(update.Message.Entities) {
 		return
 	}
-	h.reply(ctx, b, update, "Nieznana komenda. Użyj /kto_sprzata lub /sync.")
+	slog.Debug("ignoring unknown command", "text", update.Message.Text)
 }
 
 // hasCommandEntity reports whether the message carries any bot_command entity,

telegram_test.go

@@ -214,7 +214,8 @@ func TestCurrentDutyLocalMidnight(t *testing.T) {
 }
 
 // TestKtoSprzataReply checks the /kto_sprzata handler reads the cached rota and
-// replies with this week's duty rendered by formatDuty.
+// replies with this week's duty. Only the data (the names) is asserted, not the
+// exact wording, so copy tweaks don't break the test.
 func TestKtoSprzataReply(t *testing.T) {
 	rota := Rota{Weeks: []DutyWeek{week(t, "2026-06-15", "Ala", "Bartek")}}
 	svc := testService(t, rota, nil)
@@ -224,14 +225,13 @@ func TestKtoSprzataReply(t *testing.T) {
 	h.ktoSprzata(context.Background(), b, updateMsg(123, "/kto_sprzata"))
 
 	got := sent()
-	want := "Dyżur w tym tygodniu (od 2026-06-15): Ala i Bartek"
+	if len(got) != 1 || !strings.Contains(got[0], "Ala") || !strings.Contains(got[0], "Bartek") {
-	if len(got) != 1 || got[0] != want {
+		t.Fatalf("reply = %v, want one message naming Ala and Bartek", got)
-		t.Fatalf("reply = %v, want [%q]", got, want)
 	}
 }
 
-// TestSyncReplySuccess checks /sync triggers a fetch and reports the resulting
+// TestSyncReplySuccess checks /sync triggers a fetch, persists the result, and
-// week/person counts.
+// replies once.
 func TestSyncReplySuccess(t *testing.T) {
 	fetched := Rota{
 		Weeks:  []DutyWeek{week(t, "2026-06-15", "Ala", "Bartek")},
@@ -244,15 +244,17 @@ func TestSyncReplySuccess(t *testing.T) {
 
 	h.sync(context.Background(), b, updateMsg(123, "/sync"))
 
-	got := sent()
+	if got := sent(); len(got) != 1 {
-	want := "Zsynchronizowano: 1 tygodni, 3 osób."
+		t.Fatalf("replies = %v, want exactly one", got)
-	if len(got) != 1 || got[0] != want {
+	}
-		t.Fatalf("reply = %v, want [%q]", got, want)
+	rota, _ := svc.Store.Snapshot()
+	if len(rota.Weeks) != 1 {
+		t.Errorf("store weeks = %d, want 1 (sync should persist the fetch)", len(rota.Weeks))
 	}
 }
 
-// TestSyncReplyThrottled checks a /sync inside the cooldown window is rejected
+// TestSyncReplyThrottled checks a /sync inside the cooldown window does not
-// with the remaining-wait message and does not trigger a fetch.
+// trigger a fetch but still answers (so the user isn't left hanging).
 func TestSyncReplyThrottled(t *testing.T) {
 	now := fixedNow()()
 	fetch := func(context.Context) (Rota, error) {
@@ -266,16 +268,14 @@ func TestSyncReplyThrottled(t *testing.T) {
 
 	h.sync(context.Background(), b, updateMsg(123, "/sync"))
 
-	got := sent()
+	if got := sent(); len(got) != 1 {
-	want := "Synchronizowano niedawno. Spróbuj ponownie za 31s."
+		t.Fatalf("replies = %v, want exactly one", got)
-	if len(got) != 1 || got[0] != want {
-		t.Fatalf("reply = %v, want [%q]", got, want)
 	}
 }
 
-// TestSyncReplyFailure checks a failed fetch yields the generic failure message
+// TestSyncReplyFailure checks a failed fetch still yields exactly one reply,
-// (internal error details are logged, not shown). The slog.Error this emits is
+// and that internal error details are not leaked into it (they are logged
-// expected, not a harness fault.
+// instead — the slog.Error this emits is expected, not a harness fault).
 func TestSyncReplyFailure(t *testing.T) {
 	fetch := func(context.Context) (Rota, error) {
 		return Rota{}, context.DeadlineExceeded
@@ -287,15 +287,18 @@ func TestSyncReplyFailure(t *testing.T) {
 	h.sync(context.Background(), b, updateMsg(123, "/sync"))
 
 	got := sent()
-	want := "Synchronizacja nie powiodła się. Spróbuj ponownie później."
+	if len(got) != 1 {
-	if len(got) != 1 || got[0] != want {
+		t.Fatalf("replies = %v, want exactly one", got)
-		t.Fatalf("reply = %v, want [%q]", got, want)
+	}
+	if strings.Contains(got[0], context.DeadlineExceeded.Error()) {
+		t.Errorf("reply %q leaks the internal error", got[0])
 	}
 }
 
-// TestUnknownReply checks the fallback answers an unrecognized /command (a
+// TestUnknownCommandIgnored checks the fallback stays silent on an
-// message carrying a bot_command entity that no matcher claimed).
+// unrecognized /command (a bot_command entity no matcher claimed) — the bot
-func TestUnknownReply(t *testing.T) {
+// answers only its own predefined commands and ignores everything else.
+func TestUnknownCommandIgnored(t *testing.T) {
 	svc := testService(t, Rota{}, nil)
 	b, sent := newTestBot(t)
 	h := &botHandlers{svc: svc, now: fixedNow()}
@@ -307,16 +310,14 @@ func TestUnknownReply(t *testing.T) {
 	}}
 	h.unknown(context.Background(), b, cmd)
 
-	got := sent()
+	if got := sent(); len(got) != 0 {
-	want := "Nieznana komenda. Użyj /kto_sprzata lub /sync."
+		t.Fatalf("unknown command should not reply, got %v", got)
-	if len(got) != 1 || got[0] != want {
-		t.Fatalf("reply = %v, want [%q]", got, want)
 	}
 }
 
 // TestUnknownPlainTextIgnored checks ordinary chatter (no bot_command entity)
-// gets no reply, so the bot doesn't spam "Nieznana komenda" on every group
+// gets no reply — the bot stays silent on group messages, service notices, and
-// message, service notice, or reply to its own messages.
+// replies to its own messages.
 func TestUnknownPlainTextIgnored(t *testing.T) {
 	svc := testService(t, Rota{}, nil)
 	b, sent := newTestBot(t)
@@ -381,45 +382,3 @@ func TestPublishCommands(t *testing.T) {
 		t.Fatalf("PublishCommands: %v", err)
 	}
 }
-
-func TestFormatDuty(t *testing.T) {
-	tests := []struct {
-		name string
-		week DutyWeek
-		ok   bool
-		want string
-	}{
-		{
-			"both people",
-			week(t, "2026-06-15", "Ala", "Bartek"), true,
-			"Dyżur w tym tygodniu (od 2026-06-15): Ala i Bartek",
-		},
-		{
-			"only person1",
-			week(t, "2026-06-15", "Ala", ""), true,
-			"Dyżur w tym tygodniu (od 2026-06-15): Ala",
-		},
-		{
-			"only person2",
-			week(t, "2026-06-15", "", "Bartek"), true,
-			"Dyżur w tym tygodniu (od 2026-06-15): Bartek",
-		},
-		{
-			"nobody assigned",
-			week(t, "2026-06-15", "", ""), true,
-			"Dyżur w tym tygodniu (od 2026-06-15): brak przypisania",
-		},
-		{
-			"not found",
-			DutyWeek{}, false,
-			"Nie znalazłem dyżuru na ten tydzień.",
-		},
-	}
-	for _, tc := range tests {
-		t.Run(tc.name, func(t *testing.T) {
-			if got := formatDuty(tc.week, tc.ok); got != tc.want {
-				t.Errorf("formatDuty = %q, want %q", got, tc.want)
-			}
-		})
-	}
-}