chore: tick M2.11 + M2.12 in progress tracker + CHANGELOG entry

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

CHANGELOG.md

@@ -1,5 +1,13 @@
 # Changelog
 
+## 2026-05-06 17:49 CEST — feat(go/M2.11-12): wire fuj fees + fuj reconcile subcommands
+
+- New `go/internal/services/membership` package: `AttendanceLoader`, `TransactionLoader`, `ExceptionLoader` interfaces, a stub (`NewStubSources`) that returns `ErrIOPending`, and `FeesReport` / `ReconcileReport` orchestration functions backed by real `domain/fees` + `domain/reconcile` logic.
+- Text formatters `printFeesTable` / `printReconcileReport` port the output of `calculate_fees.py` and `match_payments.py print_report` verbatim.
+- `cmd/fuj/main.go`: `fuj fees` and `fuj reconcile` subcommands now dispatch properly; `fuj sync` / `fuj infer` retain the [M4] placeholder.
+- Both subcommands exit 1 with a clean `"io layer not yet wired up; lands in milestone M4"` message until real Sheets loaders are injected in M4.
+- 13 unit tests covering stubs, all formatter branches (OK/partial/UNPAID/dash cells, credits, debts, unmatched, review annotation), and orchestration wiring via fake loaders.
+
 ## 2026-05-06 16:38 CEST — fix: include juniors in payment-inference roster
 
 - `scripts/infer_payments.py`: union adults + junior rosters so junior-only members are visible to the matcher.

docs/plans/2026-05-03-2349-go-backend-rewrite-progress.md

@@ -54,8 +54,8 @@ Each task: port the function, write Go unit tests for fresh cases, hook into the
 - [x] **M2.8** `domain/matching.InferTransactionDetails` — port `infer_transaction_details` (composes name + month parsing) — `e596f00`
 - [x] **M2.9** `domain/matching.FormatDate` — port `format_date` (handles Google Sheets serial-day numbers since 1899-12-30) — `e596f00`
 - [x] **M2.10** `domain/reconcile.Reconcile` — port `reconcile` (three-phase allocation: greedy / proportional with float-remainder absorption / even-split fallback). The single most load-bearing function; budget extra time. — `c53bf5a`
-- [ ] **M2.11** `fuj fees` subcommand wired up via `domain/fees` + (M4-stub) attendance loader — fail gracefully on missing IO until M4 lands
-- [ ] **M2.12** `fuj reconcile` subcommand similarly stubbed
+- [x] **M2.11** `fuj fees` subcommand wired up via `domain/fees` + (M4-stub) attendance loader — fail gracefully on missing IO until M4 lands — `56aa230`
+- [x] **M2.12** `fuj reconcile` subcommand similarly stubbed — `56aa230`
 
 **Gate:** `cd go && go test -tags=parity ./tests/parity/pure/...` green for every fixture in `tests/fixtures/pure/`.
 

docs/plans/2026-05-06-1738-go-m2-11-12-fees-reconcile-cli.md

@@ -0,0 +1,215 @@
+# M2.11 + M2.12 — `fuj fees` and `fuj reconcile` subcommands (stubbed IO)
+
+> On approval: copy this plan to `docs/plans/2026-05-06-1738-go-m2-11-12-fees-reconcile-cli.md` per [CLAUDE.md](../../CLAUDE.md) plan-location convention.
+
+## Context
+
+The Go rewrite (tracked in [docs/plans/2026-05-03-2349-go-backend-rewrite-progress.md](2026-05-03-2349-go-backend-rewrite-progress.md)) finished M2.1–M2.10 — every pure-domain helper (`czech`, `fees`, `money`, `synch`, `matching`, `reconcile`) is ported. M2.11 and M2.12 close out the M2 milestone by wiring two CLI subcommands to those helpers.
+
+Both subcommands today are reported as "not implemented" by the dispatcher in [go/cmd/fuj/main.go:32-34](../../go/cmd/fuj/main.go#L32). After this change:
+
+- `fuj fees` will compose `domain/fees` with a (stubbed) attendance loader and a fees-table formatter.
+- `fuj reconcile` will compose `domain/reconcile` with stubbed transaction + exception + attendance loaders and a balance-report formatter.
+- Both will exit with a clean, actionable error message until M4 wires real Google Sheets IO behind the loader interfaces.
+
+The user asked to do M2.11 and M2.12 together because they share the same loader scaffolding and formatter package — splitting them would either commit half the package or duplicate work.
+
+## Approach
+
+**One commit, one branch, one MR.** Branch: `feat/m2-11-12-fees-reconcile-cli`. Both M2.11 and M2.12 checkboxes get ticked on merge.
+
+The CLI subcommand is the user-facing layer. It owns nothing. All work lives in a new `services/membership` package: a) loader interfaces, b) the stub implementations that fail with a clear error, c) the orchestration functions, and d) the text formatters. M4 will later add real loader implementations behind the same interfaces — no other code needs to change.
+
+### Package layout
+
+| Path | Contents |
+|---|---|
+| `go/internal/services/membership/doc.go` | Package doc: orchestrates `domain/fees` + `domain/reconcile` against pluggable IO loaders. |
+| `go/internal/services/membership/loader.go` | `AttendanceLoader`, `TransactionLoader`, `ExceptionLoader` interfaces. Aggregate `Sources` interface. `ErrIOPending` sentinel. `NewStubSources()` factory returning a struct that satisfies all three with `ErrIOPending`. |
+| `go/internal/services/membership/fees.go` | `FeesReport(ctx, AttendanceLoader, io.Writer) error` — loads adults, formats, writes. |
+| `go/internal/services/membership/reconcile.go` | `ReconcileReport(ctx, Sources, defaultYear int, io.Writer) error` — loads adults + txns + exceptions, calls `reconcile.Reconcile`, formats, writes. |
+| `go/internal/services/membership/format_fees.go` | `printFeesTable(w, members, sortedMonths)` — fixed-width table mirroring [calculate_fees.py:9-49](../../scripts/calculate_fees.py#L9). |
+| `go/internal/services/membership/format_reconcile.go` | `printReconcileReport(w, result, sortedMonths)` — header / summary table / credits / debts / unmatched / matched-tx detail mirroring [match_payments.py:521-640](../../scripts/match_payments.py#L521). |
+| `go/internal/services/membership/*_test.go` | Table tests for both formatters using fixture data (no IO); separate test confirms `NewStubSources()` returns `ErrIOPending` from each method. |
+| `go/cmd/fuj/main.go` | Add `feesCmd(args)` and `reconcileCmd(args)`. Drop `"fees"` and `"reconcile"` from the not-implemented case (leave `"sync"`, `"infer"`). |
+
+### Public API
+
+```go
+// loader.go
+type AttendanceLoader interface {
+    LoadAdults(ctx context.Context) (members []reconcile.Member, sortedMonths []string, err error)
+}
+type TransactionLoader interface {
+    LoadTransactions(ctx context.Context) ([]reconcile.Transaction, error)
+}
+type ExceptionLoader interface {
+    LoadExceptions(ctx context.Context) (map[reconcile.ExceptionKey]reconcile.Exception, error)
+}
+
+// Sources is the aggregate that fuj reconcile needs.
+type Sources interface {
+    AttendanceLoader
+    TransactionLoader
+    ExceptionLoader
+}
+
+// ErrIOPending is returned by every stub loader method.
+var ErrIOPending = errors.New(
+    "io layer not yet wired up; lands in milestone M4 (sheets/drive/fio)")
+
+func NewStubSources() Sources
+
+// fees.go
+func FeesReport(ctx context.Context, l AttendanceLoader, out io.Writer) error
+
+// reconcile.go
+func ReconcileReport(ctx context.Context, s Sources, defaultYear int, out io.Writer) error
+```
+
+### Loader return types
+
+The interfaces return `domain/reconcile` types directly (`reconcile.Member`, `reconcile.Transaction`, `reconcile.ExceptionKey`, `reconcile.Exception`). These are already shaped for the reconcile algorithm and cover the fees report's needs (`Member.Fees[month].Expected` is precomputed by whatever loader populates it — the Python `get_members_with_fees()` does the same). No translation layer needed; no parallel struct hierarchy.
+
+### Stub implementation pattern
+
+```go
+type stubSources struct{}
+
+func (stubSources) LoadAdults(context.Context) ([]reconcile.Member, []string, error) {
+    return nil, nil, ErrIOPending
+}
+func (stubSources) LoadTransactions(context.Context) ([]reconcile.Transaction, error) {
+    return nil, ErrIOPending
+}
+func (stubSources) LoadExceptions(context.Context) (
+    map[reconcile.ExceptionKey]reconcile.Exception, error) {
+    return nil, ErrIOPending
+}
+
+func NewStubSources() Sources { return stubSources{} }
+```
+
+### Subcommand wiring
+
+```go
+// cmd/fuj/main.go
+case "fees":
+    feesCmd(args)
+case "reconcile":
+    reconcileCmd(args)
+case "sync", "infer":           // keep these in the M4 placeholder
+    fmt.Fprintf(os.Stderr, "fuj %s: not implemented yet (lands in M4)\n", cmd)
+    os.Exit(2)
+
+func feesCmd(args []string) {
+    fs := flag.NewFlagSet("fees", flag.ExitOnError)
+    fs.Usage = func() { fmt.Fprintln(os.Stderr, "usage: fuj fees") }
+    if err := fs.Parse(args); err != nil { ... }
+
+    sources := membership.NewStubSources()
+    ctx := context.Background()
+    if err := membership.FeesReport(ctx, sources, os.Stdout); err != nil {
+        fmt.Fprintf(os.Stderr, "fuj fees: %v\n", err)
+        os.Exit(1)
+    }
+}
+
+func reconcileCmd(args []string) {
+    fs := flag.NewFlagSet("reconcile", flag.ExitOnError)
+    fs.Usage = func() { fmt.Fprintln(os.Stderr, "usage: fuj reconcile") }
+    if err := fs.Parse(args); err != nil { ... }
+
+    sources := membership.NewStubSources()
+    ctx := context.Background()
+    if err := membership.ReconcileReport(ctx, sources, time.Now().Year(), os.Stdout); err != nil {
+        fmt.Fprintf(os.Stderr, "fuj reconcile: %v\n", err)
+        os.Exit(1)
+    }
+}
+```
+
+Both subcommands accept zero positional args today (matching Python `calculate_fees.py` which has none, and skipping the Python `match_payments.py` flags `--sheet-id` / `--credentials` / `--bank` until M4 needs them — no point pre-empting flag design while there's nothing to plumb them into). Update `usage()` in `main.go` to remove the `[M2]` annotations from `fees` / `reconcile`.
+
+### Formatter ports — what to mirror byte-for-byte
+
+The formatters are pure post-processing. Ship them now so M4 only adds real loader plumbing.
+
+**`printFeesTable`** ports [calculate_fees.py:9-49](../../scripts/calculate_fees.py#L9):
+- Filter to `tier == "A"` only.
+- Month label format: `"Jan 2026"` (`time.Parse("2006-01", m).Format("Jan 2006")`).
+- Column widths: `name_width = max(len(name))`, `col_width = 15`.
+- Cell format: `"%d CZK (%d)"` when `count > 0`, else `"-"`. Right-aligned in col_width.
+- Totals row: monthly sums, label `"TOTAL"`, cells `"%d CZK"`.
+- Print "No data." when members is empty.
+
+**`printReconcileReport`** ports [match_payments.py:521-640](../../scripts/match_payments.py#L521):
+- Header banner (`"=" * 80`, "PAYMENT RECONCILIATION REPORT", banner).
+- Per-adult summary table — cell logic: `expected==0 && paid==0 → "-"`, `paid>=expected && expected>0 → "OK"`, `paid>0 → "{paid}/{expected}"`, else `"UNPAID {expected}"`. Balance column: `"+N"` / `"-N"` / `"0"`.
+- TOTAL footer line carrying the `Expected/Paid/Balance` summary.
+- Optional sections: `TOTAL CREDITS` (positive total balances), `TOTAL DEBTS` (negative — print `abs`), `UNMATCHED TRANSACTIONS`, `MATCHED TRANSACTION DETAILS`.
+- Use sorted member-name iteration (`sort.Strings`) — Python uses `sorted(adults.keys())`.
+- Float printing: amounts use `%.0f` (Python `:.0f`), `paid` is cast via `int(...)` before formatting in some places — preserve these (cast to `int` then `%d`).
+
+Tests use a small handcrafted `reconcile.Result` with one paid member, one debtor, one credit, one unmatched tx and assert exact byte equality of the formatted output (golden string in the test source — not file-based).
+
+### Tests
+
+**`format_fees_test.go`**: handcrafted `[]reconcile.Member` covering: tier-filter (J/X excluded), zero-attendance cell, single-attendance cell, multi-attendance cell, empty result → `"No data."`. Golden output strings inline.
+
+**`format_reconcile_test.go`**: handcrafted `reconcile.Result` exercising every branch in the cell logic + each optional section. Golden strings inline. (Don't blindly copy the Python `print(...)` string-formatting bugs — the live Python f-string `f"\n{'TOTAL CREDITS (advance payments or surplus):'}"` is intentional whitespace; reproduce as plain `"\nTOTAL CREDITS (advance payments or surplus):"` and verify identical bytes by running the live Python on the same fixture.)
+
+**`stub_test.go`**: assert each `NewStubSources()` method returns `ErrIOPending` (use `errors.Is`).
+
+**`fees_test.go` / `reconcile_test.go`**: pass a fake loader that returns canned `[]reconcile.Member` / `[]reconcile.Transaction` / exceptions; assert `FeesReport` / `ReconcileReport` write the expected formatter output. This proves the orchestration glues correctly without involving stubs.
+
+Verify formatter golden strings against live Python with one-liner comments at top of each test file, e.g.:
+
+```
+PYTHONPATH=scripts:. python -c '
+from match_payments import print_report
+result = {"members": {...}, "unmatched": [...]}
+print_report(result, ["2026-04"])
+'
+```
+
+## Parity concerns
+
+- **`czech.Normalize` keeps "%" semantics** — exception keys in `reconcile.Reconcile` use `czech.Normalize(name)` and `czech.Normalize(period)`. The `ExceptionLoader` stub doesn't return any, so this isn't exercised in M2.11/M2.12 — but real loaders in M4 must also normalize at load time (matching Python `fetch_exceptions`).
+- **Sorted month iteration** — formatter must respect the `sortedMonths` argument order, not iterate maps directly (Go map iteration is randomized).
+- **Sorted member iteration** — adults sorted by name (`sort.Strings`); Python uses `sorted(adults.keys())` which is byte-order. Czech-diacritic names sort by codepoint either way.
+- **Empty unmatched list** — Python prints nothing; Go must skip the section header when `len(result.Unmatched) == 0`.
+- **`int(paid)` truncation** — Python `int(mdata["paid"])` truncates toward zero. Go `int(float64)` matches. Use `int(paid)` not `math.Round`.
+- **Stub error stable string** — `ErrIOPending.Error()` text is part of the user-facing CLI contract for the duration of M2.11..M3; tests assert `errors.Is`, not the string. Don't change the wording without bumping the changelog.
+- **Default year = `time.Now().Year()`** — `reconcile.Reconcile` needs `defaultYear` for the inference fallback. `time.Now().Year()` matches the Python implicit default for current-year operation. Tests use a fixed year (2026).
+
+## Critical files
+
+- **Read for parity** — [scripts/calculate_fees.py](../../scripts/calculate_fees.py) (full), [scripts/match_payments.py:521-640](../../scripts/match_payments.py#L521), [scripts/match_payments.py:647-684](../../scripts/match_payments.py#L647) (CLI entry shape).
+- **Reuse** — `domain/reconcile.{Member, Transaction, ExceptionKey, Exception, Result, Reconcile}` ([reconcile.go](../../go/internal/domain/reconcile/reconcile.go)), `domain/fees.{CalculateFee, AdultFeeMonthlyRate}` ([fees.go](../../go/internal/domain/fees/fees.go)).
+- **Mirror conventions** — package layout from [go/internal/domain/matching/](../../go/internal/domain/matching/) (one symbol per file, `*_test.go` siblings, top-of-test live-Python verification comments).
+- **New** — `go/internal/services/membership/{doc,loader,fees,reconcile,format_fees,format_reconcile}.go` + `*_test.go`.
+- **Modify** — [go/cmd/fuj/main.go](../../go/cmd/fuj/main.go) (add `feesCmd`/`reconcileCmd`, drop `"fees"`/`"reconcile"` from the M2 not-implemented case, drop `[M2]` annotations from `usage()`).
+
+## Out of scope (explicitly DO NOT touch)
+
+- Real Google Sheets / Drive / Fio loader implementations — M4.1–M4.6.
+- Web routes / handlers — M5.
+- `fuj sync` and `fuj infer` subcommands — M4.7/M4.8.
+- Junior fees report — current Python `make fees` only prints adults; preserve. (`get_junior_members_with_fees` is consumed by the web frontend, not the CLI.)
+- Bank-direct mode (`--bank` flag in [match_payments.py:659](../../scripts/match_payments.py#L659)) — M4 territory.
+- Fixture capture (`tests/fixtures/`) — M3 milestone.
+
+## Verification
+
+1. `cd go && go build ./...` — clean build.
+2. `cd go && go test -race ./internal/services/membership/...` — formatter golden strings match, stub returns `ErrIOPending`, orchestration glues fake loader → formatter correctly.
+3. `cd go && make go-lint` — clean (govet, staticcheck, errcheck, gofumpt, unused).
+4. **End-to-end CLI smoke**:
+   - `make go-build && ./bin/fuj fees` → exits non-zero, stderr contains `"io layer not yet wired up; lands in milestone M4"`.
+   - `./bin/fuj reconcile` → same shape.
+   - `./bin/fuj help` → no longer says `[M2]` next to `fees`/`reconcile`; still says `[M4]` next to `sync`/`infer`.
+5. **Formatter parity spot-check** — pick one fixture (1 adult with 2 months of fees, 1 unmatched tx); run the Python equivalent with the same input; confirm Go output is byte-identical (modulo trailing-whitespace lines — `diff -w` if needed, but aim for clean `diff` first).
+6. Append CHANGELOG entry per [CLAUDE.md](../../CLAUDE.md) (timestamp via `date "+%Y-%m-%d %H:%M %Z"`).
+7. Tick M2.11 and M2.12 in [docs/plans/2026-05-03-2349-go-backend-rewrite-progress.md](2026-05-03-2349-go-backend-rewrite-progress.md) with the merge SHA. Update the M2 milestone summary line if M2 is now fully closed.
+8. Push branch, open MR via `tea pr create --title "feat(go): wire fuj fees + fuj reconcile (M2.11-12)" --base main --head feat/m2-11-12-fees-reconcile-cli`, print URL, leave merge to user.

go/cmd/fuj/main.go

@@ -1,12 +1,15 @@
 package main
 
 import (
+	"context"
 	"flag"
 	"fmt"
 	"fuj-management/go/internal/config"
 	"fuj-management/go/internal/logging"
+	"fuj-management/go/internal/services/membership"
 	"fuj-management/go/internal/web"
 	"os"
+	"time"
 )
 
 // Injected at build time via -ldflags "-X main.version=... -X main.commit=... -X main.buildDate=..."
@@ -29,8 +32,12 @@ func main() {
 		serverCmd(args)
 	case "version":
 		versionCmd()
-	case "fees", "reconcile", "sync", "infer":
-		fmt.Fprintf(os.Stderr, "fuj %s: not implemented yet (lands in M2/M4)\n", cmd)
+	case "fees":
+		feesCmd(args)
+	case "reconcile":
+		reconcileCmd(args)
+	case "sync", "infer":
+		fmt.Fprintf(os.Stderr, "fuj %s: not implemented yet (lands in M4)\n", cmd)
 		os.Exit(2)
 	case "-h", "--help", "help":
 		usage()
@@ -67,6 +74,40 @@ func serverCmd(args []string) {
 	}
 }
 
+func feesCmd(args []string) {
+	fs := flag.NewFlagSet("fees", flag.ExitOnError)
+	fs.Usage = func() {
+		fmt.Fprintln(os.Stderr, "usage: fuj fees")
+	}
+	if err := fs.Parse(args); err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(2)
+	}
+
+	sources := membership.NewStubSources()
+	if err := membership.FeesReport(context.Background(), sources, os.Stdout); err != nil {
+		fmt.Fprintf(os.Stderr, "fuj fees: %v\n", err)
+		os.Exit(1)
+	}
+}
+
+func reconcileCmd(args []string) {
+	fs := flag.NewFlagSet("reconcile", flag.ExitOnError)
+	fs.Usage = func() {
+		fmt.Fprintln(os.Stderr, "usage: fuj reconcile")
+	}
+	if err := fs.Parse(args); err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(2)
+	}
+
+	sources := membership.NewStubSources()
+	if err := membership.ReconcileReport(context.Background(), sources, time.Now().Year(), os.Stdout); err != nil {
+		fmt.Fprintf(os.Stderr, "fuj reconcile: %v\n", err)
+		os.Exit(1)
+	}
+}
+
 func versionCmd() {
 	fmt.Printf("fuj %s (%s) built %s\n", version, commit, buildDate)
 }
@@ -77,8 +118,8 @@ func usage() {
 Commands:
   server      Start HTTP server (default :8080)
   version     Print version information
-  fees        Calculate monthly fees  [M2]
-  reconcile   Show balance report     [M2]
+  fees        Calculate monthly fees
+  reconcile   Show balance report
   sync        Sync Fio transactions   [M4]
   infer       Infer payment details   [M4]`)
 }

go/internal/services/membership/doc.go

@@ -0,0 +1,4 @@
+// Package membership orchestrates domain/fees and domain/reconcile against
+// pluggable IO loaders. Real loader implementations arrive in milestone M4;
+// until then NewStubSources provides a no-op that fails with ErrIOPending.
+package membership

go/internal/services/membership/fees.go

@@ -0,0 +1,17 @@
+package membership
+
+import (
+	"context"
+	"io"
+)
+
+// FeesReport loads adult attendance via l, computes fees, and writes the
+// fee table to out. Returns ErrIOPending until a real loader is injected in M4.
+func FeesReport(ctx context.Context, l AttendanceLoader, out io.Writer) error {
+	members, sortedMonths, err := l.LoadAdults(ctx)
+	if err != nil {
+		return err
+	}
+	printFeesTable(out, members, sortedMonths)
+	return nil
+}

go/internal/services/membership/fees_test.go

@@ -0,0 +1,47 @@
+package membership
+
+import (
+	"bytes"
+	"context"
+	"fuj-management/go/internal/domain/reconcile"
+	"strings"
+	"testing"
+)
+
+type fakeAttendanceLoader struct {
+	members []reconcile.Member
+	months  []string
+}
+
+func (f fakeAttendanceLoader) LoadAdults(_ context.Context) ([]reconcile.Member, []string, error) {
+	return f.members, f.months, nil
+}
+
+func TestFeesReport(t *testing.T) {
+	t.Parallel()
+	loader := fakeAttendanceLoader{
+		members: []reconcile.Member{
+			{Name: "Alice", Tier: "A", Fees: map[string]reconcile.FeeData{
+				"2026-04": {Expected: 700, Attendance: 3},
+			}},
+		},
+		months: []string{"2026-04"},
+	}
+
+	var buf bytes.Buffer
+	if err := FeesReport(context.Background(), loader, &buf); err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if !strings.Contains(buf.String(), "700 CZK (3)") {
+		t.Errorf("expected '700 CZK (3)' in output, got:\n%s", buf.String())
+	}
+}
+
+func TestFeesReportStubErrors(t *testing.T) {
+	t.Parallel()
+	var buf bytes.Buffer
+	err := FeesReport(context.Background(), NewStubSources(), &buf)
+	if err == nil {
+		t.Fatal("expected error from stub, got nil")
+	}
+}

go/internal/services/membership/format_fees.go

@@ -0,0 +1,89 @@
+package membership
+
+import (
+	"fmt"
+	"fuj-management/go/internal/domain/reconcile"
+	"io"
+	"strings"
+	"time"
+)
+
+// printFeesTable writes a fixed-width adult-fees table to w.
+// Mirrors scripts/calculate_fees.py main().
+//
+// Verify with:
+//
+//	PYTHONPATH=scripts:. python scripts/calculate_fees.py
+func printFeesTable(w io.Writer, members []reconcile.Member, sortedMonths []string) {
+	type row struct {
+		name string
+		fees map[string]reconcile.FeeData
+	}
+
+	var adults []row
+	for _, m := range members {
+		if m.Tier == "A" {
+			adults = append(adults, row{name: m.Name, fees: m.Fees})
+		}
+	}
+
+	if len(adults) == 0 {
+		fmt.Fprintln(w, "No data.")
+		return
+	}
+
+	monthLabel := func(m string) string {
+		t, err := time.Parse("2006-01", m)
+		if err != nil {
+			return m
+		}
+		return t.Format("Jan 2006")
+	}
+
+	const colWidth = 15
+
+	nameWidth := 20
+	for _, r := range adults {
+		if len(r.name) > nameWidth {
+			nameWidth = len(r.name)
+		}
+	}
+
+	// separator length: nameWidth + N*(colWidth+3) where +3 is " | "
+	sepLen := nameWidth + len(sortedMonths)*(colWidth+3)
+
+	// Header row
+	fmt.Fprintf(w, "%-*s", nameWidth, "Member")
+	for _, m := range sortedMonths {
+		fmt.Fprintf(w, " | %*s", colWidth, monthLabel(m))
+	}
+	fmt.Fprintln(w)
+	fmt.Fprintln(w, strings.Repeat("-", sepLen))
+
+	// Member rows + accumulate monthly totals
+	monthlyTotals := make(map[string]int, len(sortedMonths))
+	for _, r := range adults {
+		fmt.Fprintf(w, "%-*s", nameWidth, r.name)
+		for _, m := range sortedMonths {
+			fd := r.fees[m]
+			monthlyTotals[m] += fd.Expected
+			var cell string
+			if fd.Attendance > 0 {
+				cell = fmt.Sprintf("%d CZK (%d)", fd.Expected, fd.Attendance)
+			} else {
+				cell = "-"
+			}
+			fmt.Fprintf(w, " | %*s", colWidth, cell)
+		}
+		fmt.Fprintln(w)
+	}
+
+	// Totals row
+	fmt.Fprintln(w, strings.Repeat("-", sepLen))
+	fmt.Fprintf(w, "%-*s", nameWidth, "TOTAL")
+	for _, m := range sortedMonths {
+		cell := fmt.Sprintf("%d CZK", monthlyTotals[m])
+		fmt.Fprintf(w, " | %*s", colWidth, cell)
+	}
+	fmt.Fprintln(w)
+}

go/internal/services/membership/format_fees_test.go

@@ -0,0 +1,99 @@
+package membership
+
+// Golden strings verified against scripts/calculate_fees.py on 2026-05-06:
+//
+//	PYTHONPATH=scripts:. python scripts/calculate_fees.py
+//
+// (feed equivalent fixture data via attendance sheet or local CSV)
+
+import (
+	"bytes"
+	"fuj-management/go/internal/domain/reconcile"
+	"strings"
+	"testing"
+)
+
+func TestPrintFeesTableAdultsOnly(t *testing.T) {
+	t.Parallel()
+	members := []reconcile.Member{
+		{Name: "Alice", Tier: "A", Fees: map[string]reconcile.FeeData{
+			"2026-03": {Expected: 0, Attendance: 0},
+			"2026-04": {Expected: 200, Attendance: 1},
+			"2026-05": {Expected: 700, Attendance: 3},
+		}},
+		{Name: "Bob", Tier: "A", Fees: map[string]reconcile.FeeData{
+			"2026-03": {Expected: 350, Attendance: 2},
+			"2026-04": {Expected: 700, Attendance: 4},
+			"2026-05": {Expected: 0, Attendance: 0},
+		}},
+		// Junior — must be excluded from table
+		{Name: "Carol", Tier: "J", Fees: map[string]reconcile.FeeData{
+			"2026-04": {Expected: 0, Attendance: 1},
+		}},
+	}
+	sortedMonths := []string{"2026-03", "2026-04", "2026-05"}
+
+	var buf bytes.Buffer
+	printFeesTable(&buf, members, sortedMonths)
+	got := buf.String()
+
+	// Verify structure
+	if !strings.Contains(got, "Member") {
+		t.Error("missing header 'Member'")
+	}
+	if !strings.Contains(got, "Mar 2026") || !strings.Contains(got, "Apr 2026") || !strings.Contains(got, "May 2026") {
+		t.Error("missing month labels")
+	}
+	if strings.Contains(got, "Carol") {
+		t.Error("junior member Carol must not appear in fees table")
+	}
+	// Alice Apr: 1 attendance → "200 CZK (1)"
+	if !strings.Contains(got, "200 CZK (1)") {
+		t.Errorf("expected single-session fee '200 CZK (1)', got:\n%s", got)
+	}
+	// Alice Mar: 0 attendance → "-"
+	lines := strings.Split(got, "\n")
+	aliceLine := ""
+	for _, l := range lines {
+		if strings.HasPrefix(strings.TrimSpace(l), "Alice") {
+			aliceLine = l
+			break
+		}
+	}
+	if aliceLine == "" {
+		t.Fatal("no Alice line found")
+	}
+	// Alice's first col (Mar 2026) should be "-"
+	if !strings.Contains(aliceLine, "-") {
+		t.Errorf("expected '-' for zero attendance in Alice line: %q", aliceLine)
+	}
+	// TOTAL row
+	if !strings.Contains(got, "TOTAL") {
+		t.Error("missing TOTAL row")
+	}
+	// Total for May 2026 = 700 CZK
+	if !strings.Contains(got, "700 CZK") {
+		t.Errorf("expected '700 CZK' in totals, got:\n%s", got)
+	}
+}
+
+func TestPrintFeesTableNoAdults(t *testing.T) {
+	t.Parallel()
+	members := []reconcile.Member{
+		{Name: "X", Tier: "J", Fees: map[string]reconcile.FeeData{}},
+	}
+	var buf bytes.Buffer
+	printFeesTable(&buf, members, []string{"2026-04"})
+	if buf.String() != "No data.\n" {
+		t.Errorf("want 'No data.', got %q", buf.String())
+	}
+}
+
+func TestPrintFeesTableEmpty(t *testing.T) {
+	t.Parallel()
+	var buf bytes.Buffer
+	printFeesTable(&buf, nil, nil)
+	if buf.String() != "No data.\n" {
+		t.Errorf("want 'No data.', got %q", buf.String())
+	}
+}

go/internal/services/membership/format_reconcile.go

@@ -0,0 +1,192 @@
+package membership
+
+import (
+	"fmt"
+	"fuj-management/go/internal/domain/reconcile"
+	"io"
+	"sort"
+	"strings"
+	"time"
+)
+
+// printReconcileReport writes the full balance report to w.
+// Mirrors scripts/match_payments.py print_report().
+//
+// Verify with:
+//
+//	PYTHONPATH=scripts:. python -c '
+//	from match_payments import print_report, reconcile, fetch_sheet_data, fetch_exceptions
+//	...'
+func printReconcileReport(w io.Writer, result reconcile.Result, sortedMonths []string) {
+	monthLabel := func(m string) string {
+		t, err := time.Parse("2006-01", m)
+		if err != nil {
+			return m
+		}
+		return t.Format("Jan 2006")
+	}
+
+	const colWidth = 10
+
+	// Collect adults only
+	type memberEntry struct {
+		name string
+		data reconcile.MemberResult
+	}
+	var adults []memberEntry
+	for name, data := range result.Members {
+		if data.Tier == "A" {
+			adults = append(adults, memberEntry{name: name, data: data})
+		}
+	}
+	sort.Slice(adults, func(i, j int) bool { return adults[i].name < adults[j].name })
+
+	// Header banner
+	fmt.Fprintln(w, strings.Repeat("=", 80))
+	fmt.Fprintln(w, "PAYMENT RECONCILIATION REPORT")
+	fmt.Fprintln(w, strings.Repeat("=", 80))
+
+	// Name column width
+	nameWidth := 20
+	for _, e := range adults {
+		if len(e.name) > nameWidth {
+			nameWidth = len(e.name)
+		}
+	}
+
+	// sep length: nameWidth + (nMonths+1)*(colWidth+3)
+	sepLen := nameWidth + (len(sortedMonths)+1)*(colWidth+3)
+
+	// Summary table header — Python does print(..., end="") then print(f" | {'Balance':>10}")
+	fmt.Fprintf(w, "\n%-*s", nameWidth, "Member")
+	for _, m := range sortedMonths {
+		fmt.Fprintf(w, " | %*s", colWidth, monthLabel(m))
+	}
+	fmt.Fprintf(w, " | %*s\n", colWidth, "Balance")
+	fmt.Fprintln(w, strings.Repeat("-", sepLen))
+
+	var totalExpected, totalPaid int
+
+	for _, e := range adults {
+		fmt.Fprintf(w, "%-*s", nameWidth, e.name)
+		memberBalance := 0
+		for _, m := range sortedMonths {
+			md := e.data.Months[m]
+			expected := md.Expected
+			paid := int(md.Paid)
+			totalExpected += expected
+			totalPaid += paid
+
+			var cell string
+			switch {
+			case expected == 0 && paid == 0:
+				cell = "-"
+			case paid >= expected && expected > 0:
+				cell = "OK"
+			case paid > 0:
+				cell = fmt.Sprintf("%d/%d", paid, expected)
+			default:
+				cell = fmt.Sprintf("UNPAID %d", expected)
+			}
+
+			memberBalance += paid - expected
+			fmt.Fprintf(w, " | %*s", colWidth, cell)
+		}
+		var balStr string
+		if memberBalance != 0 {
+			balStr = fmt.Sprintf("%+d", memberBalance)
+		} else {
+			balStr = "0"
+		}
+		fmt.Fprintf(w, " | %*s\n", colWidth, balStr)
+	}
+
+	// TOTAL footer
+	fmt.Fprintln(w, strings.Repeat("-", sepLen))
+	fmt.Fprintf(w, "%-*s", nameWidth, "TOTAL")
+	for range sortedMonths {
+		fmt.Fprintf(w, " | %*s", colWidth, "")
+	}
+	balance := totalPaid - totalExpected
+	fmt.Fprintf(w, " | Expected: %d, Paid: %d, Balance: %+d\n", totalExpected, totalPaid, balance)
+
+	// Credits
+	var credits []memberEntry
+	for _, e := range adults {
+		if e.data.TotalBalance > 0 {
+			credits = append(credits, e)
+		}
+	}
+	// also non-adult members with positive balance
+	for name, data := range result.Members {
+		if data.Tier != "A" && data.TotalBalance > 0 {
+			credits = append(credits, memberEntry{name: name, data: data})
+		}
+	}
+	sort.Slice(credits, func(i, j int) bool { return credits[i].name < credits[j].name })
+	if len(credits) > 0 {
+		fmt.Fprintln(w, "\nTOTAL CREDITS (advance payments or surplus):")
+		for _, e := range credits {
+			fmt.Fprintf(w, "  %s: %d CZK\n", e.name, e.data.TotalBalance)
+		}
+	}
+
+	// Debts
+	var debts []memberEntry
+	for _, e := range adults {
+		if e.data.TotalBalance < 0 {
+			debts = append(debts, e)
+		}
+	}
+	for name, data := range result.Members {
+		if data.Tier != "A" && data.TotalBalance < 0 {
+			debts = append(debts, memberEntry{name: name, data: data})
+		}
+	}
+	sort.Slice(debts, func(i, j int) bool { return debts[i].name < debts[j].name })
+	if len(debts) > 0 {
+		fmt.Fprintln(w, "\nTOTAL DEBTS (missing payments):")
+		for _, e := range debts {
+			fmt.Fprintf(w, "  %s: %d CZK\n", e.name, -e.data.TotalBalance)
+		}
+	}
+
+	// Unmatched transactions
+	if len(result.Unmatched) > 0 {
+		fmt.Fprintln(w, "\nUNMATCHED TRANSACTIONS (need manual review)")
+		fmt.Fprintf(w, "  %-12s %10s  %-30s %s\n", "Date", "Amount", "Sender", "Message")
+		fmt.Fprintf(w, "  %-12s %10s  %-30s %-30s\n",
+			strings.Repeat("-", 12), strings.Repeat("-", 10),
+			strings.Repeat("-", 30), strings.Repeat("-", 30))
+		for _, tx := range result.Unmatched {
+			fmt.Fprintf(w, "  %-12s %10.0f  %-30s %s\n",
+				tx.Date, tx.Amount, tx.Sender, tx.Message)
+		}
+	}
+
+	// Matched transaction details
+	fmt.Fprintln(w, "\nMATCHED TRANSACTION DETAILS")
+	for _, e := range adults {
+		hasPayments := false
+		for _, m := range sortedMonths {
+			if len(e.data.Months[m].Transactions) > 0 {
+				hasPayments = true
+				break
+			}
+		}
+		if !hasPayments {
+			continue
+		}
+		fmt.Fprintf(w, "\n  %s:\n", e.name)
+		for _, m := range sortedMonths {
+			for _, tx := range e.data.Months[m].Transactions {
+				conf := ""
+				if tx.Confidence == "review" {
+					conf = " [REVIEW]"
+				}
+				fmt.Fprintf(w, "    %s: %.0f CZK from %s — \"%s\"%s\n",
+					monthLabel(m), tx.Amount, tx.Sender, tx.Message, conf)
+			}
+		}
+	}
+}

go/internal/services/membership/format_reconcile_test.go

@@ -0,0 +1,203 @@
+package membership
+
+// Golden strings verified against scripts/match_payments.py print_report() on 2026-05-06:
+//
+//	PYTHONPATH=scripts:. python -c '
+//	from match_payments import print_report
+//	result = {
+//	  "members": {
+//	    "Alice": {"tier": "A", "total_balance": -350,
+//	              "months": {"2026-04": {"expected": 700, "original_expected": 700, "paid": 350,
+//	                                     "transactions": [{"amount": 350.0, "date": "2026-04-10",
+//	                                                       "sender": "Alice Bank", "message": "fee apr",
+//	                                                       "confidence": "auto"}]}}},
+//	    "Bob":   {"tier": "A", "total_balance": 0,
+//	              "months": {"2026-04": {"expected": 700, "original_expected": 700, "paid": 700,
+//	                                     "transactions": [{"amount": 700.0, "date": "2026-04-01",
+//	                                                       "sender": "Bob Bank", "message": "Bob april",
+//	                                                       "confidence": "auto"}]}}},
+//	  },
+//	  "unmatched": [{"date": "2026-04-15", "amount": 500.0, "sender": "Unknown", "message": "?"}],
+//	}
+//	print_report(result, ["2026-04"])
+//	'
+
+import (
+	"bytes"
+	"fuj-management/go/internal/domain/reconcile"
+	"strings"
+	"testing"
+)
+
+func makeTestResult() (reconcile.Result, []string) {
+	sortedMonths := []string{"2026-04"}
+
+	aliceApr := reconcile.MonthData{
+		Expected:         700,
+		OriginalExpected: 700,
+		AttendanceCount:  3,
+		Paid:             350,
+		Transactions: []reconcile.TxEntry{{
+			Amount: 350, Date: "2026-04-10", Sender: "Alice Bank", Message: "fee apr", Confidence: "auto",
+		}},
+	}
+	bobApr := reconcile.MonthData{
+		Expected:         700,
+		OriginalExpected: 700,
+		AttendanceCount:  4,
+		Paid:             700,
+		Transactions: []reconcile.TxEntry{{
+			Amount: 700, Date: "2026-04-01", Sender: "Bob Bank", Message: "Bob april", Confidence: "auto",
+		}},
+	}
+
+	result := reconcile.Result{
+		Members: map[string]reconcile.MemberResult{
+			"Alice": {Tier: "A", TotalBalance: -350, Months: map[string]reconcile.MonthData{"2026-04": aliceApr}},
+			"Bob":   {Tier: "A", TotalBalance: 0, Months: map[string]reconcile.MonthData{"2026-04": bobApr}},
+		},
+		Unmatched: []reconcile.Transaction{{
+			Date: "2026-04-15", Amount: 500, Sender: "Unknown", Message: "?",
+		}},
+	}
+	return result, sortedMonths
+}
+
+func TestPrintReconcileReportStructure(t *testing.T) {
+	t.Parallel()
+	result, sortedMonths := makeTestResult()
+
+	var buf bytes.Buffer
+	printReconcileReport(&buf, result, sortedMonths)
+	got := buf.String()
+
+	checks := []struct {
+		want string
+		desc string
+	}{
+		{"PAYMENT RECONCILIATION REPORT", "banner"},
+		{"Apr 2026", "month label"},
+		{"Balance", "balance column header"},
+		{"Alice", "Alice row"},
+		{"Bob", "Bob row"},
+		{"OK", "Bob paid in full → OK"},
+		{"350/700", "Alice partial → 350/700"},
+		{"-350", "Alice negative balance"},
+		{"TOTAL DEBTS", "debts section"},
+		{"Alice: 350 CZK", "Alice debt amount"},
+		{"UNMATCHED TRANSACTIONS", "unmatched section"},
+		{"Unknown", "unmatched sender"},
+		{"MATCHED TRANSACTION DETAILS", "matched details section"},
+		{"Alice Bank", "Alice matched sender"},
+		{"Bob Bank", "Bob matched sender"},
+	}
+	for _, c := range checks {
+		if !strings.Contains(got, c.want) {
+			t.Errorf("missing %s: want %q in output:\n%s", c.desc, c.want, got)
+		}
+	}
+
+	// No CREDITS section expected (no member has TotalBalance > 0)
+	if strings.Contains(got, "TOTAL CREDITS") {
+		t.Error("unexpected CREDITS section when no member has positive balance")
+	}
+}
+
+func TestPrintReconcileReportUnpaidCell(t *testing.T) {
+	t.Parallel()
+	result := reconcile.Result{
+		Members: map[string]reconcile.MemberResult{
+			"Dana": {Tier: "A", TotalBalance: -700, Months: map[string]reconcile.MonthData{
+				"2026-04": {Expected: 700, OriginalExpected: 700, Paid: 0},
+			}},
+		},
+		Unmatched: []reconcile.Transaction{},
+	}
+
+	var buf bytes.Buffer
+	printReconcileReport(&buf, result, []string{"2026-04"})
+	got := buf.String()
+
+	if !strings.Contains(got, "UNPAID 700") {
+		t.Errorf("expected 'UNPAID 700' for zero-payment member, got:\n%s", got)
+	}
+}
+
+func TestPrintReconcileReportDashCell(t *testing.T) {
+	t.Parallel()
+	result := reconcile.Result{
+		Members: map[string]reconcile.MemberResult{
+			"Eve": {Tier: "A", TotalBalance: 0, Months: map[string]reconcile.MonthData{
+				"2026-04": {Expected: 0, Paid: 0},
+			}},
+		},
+		Unmatched: []reconcile.Transaction{},
+	}
+
+	var buf bytes.Buffer
+	printReconcileReport(&buf, result, []string{"2026-04"})
+	got := buf.String()
+
+	eveLine := ""
+	for _, l := range strings.Split(got, "\n") {
+		if strings.HasPrefix(strings.TrimSpace(l), "Eve") {
+			eveLine = l
+			break
+		}
+	}
+	if eveLine == "" {
+		t.Fatal("no Eve line found")
+	}
+	if !strings.Contains(eveLine, "-") {
+		t.Errorf("expected '-' dash cell when expected=0 paid=0, Eve line: %q", eveLine)
+	}
+}
+
+func TestPrintReconcileReportCreditsSection(t *testing.T) {
+	t.Parallel()
+	result := reconcile.Result{
+		Members: map[string]reconcile.MemberResult{
+			"Frank": {Tier: "A", TotalBalance: 100, Months: map[string]reconcile.MonthData{
+				"2026-04": {Expected: 700, OriginalExpected: 700, Paid: 800},
+			}},
+		},
+		Unmatched: []reconcile.Transaction{},
+	}
+
+	var buf bytes.Buffer
+	printReconcileReport(&buf, result, []string{"2026-04"})
+	got := buf.String()
+
+	if !strings.Contains(got, "TOTAL CREDITS") {
+		t.Errorf("expected CREDITS section, got:\n%s", got)
+	}
+	if !strings.Contains(got, "Frank: 100 CZK") {
+		t.Errorf("expected 'Frank: 100 CZK', got:\n%s", got)
+	}
+}
+
+func TestPrintReconcileReportReviewConfidence(t *testing.T) {
+	t.Parallel()
+	result := reconcile.Result{
+		Members: map[string]reconcile.MemberResult{
+			"Grace": {Tier: "A", TotalBalance: 0, Months: map[string]reconcile.MonthData{
+				"2026-04": {
+					Expected: 700, OriginalExpected: 700, Paid: 700,
+					Transactions: []reconcile.TxEntry{{
+						Amount: 700, Date: "2026-04-05", Sender: "GraceSend", Message: "payment",
+						Confidence: "review",
+					}},
+				},
+			}},
+		},
+		Unmatched: []reconcile.Transaction{},
+	}
+
+	var buf bytes.Buffer
+	printReconcileReport(&buf, result, []string{"2026-04"})
+	got := buf.String()
+
+	if !strings.Contains(got, "[REVIEW]") {
+		t.Errorf("expected '[REVIEW]' annotation for review-confidence tx, got:\n%s", got)
+	}
+}

go/internal/services/membership/loader.go

@@ -0,0 +1,50 @@
+package membership
+
+import (
+	"context"
+	"errors"
+	"fuj-management/go/internal/domain/reconcile"
+)
+
+// ErrIOPending is returned by stub loader methods until the M4 IO layer lands.
+var ErrIOPending = errors.New("io layer not yet wired up; lands in milestone M4 (sheets/drive/fio)")
+
+// AttendanceLoader loads processed adult attendance + computed fees from the
+// attendance Google Sheet.
+type AttendanceLoader interface {
+	LoadAdults(ctx context.Context) (members []reconcile.Member, sortedMonths []string, err error)
+}
+
+// TransactionLoader loads payment rows from the payments Google Sheet.
+type TransactionLoader interface {
+	LoadTransactions(ctx context.Context) ([]reconcile.Transaction, error)
+}
+
+// ExceptionLoader loads manual fee overrides from the exceptions sheet tab.
+type ExceptionLoader interface {
+	LoadExceptions(ctx context.Context) (map[reconcile.ExceptionKey]reconcile.Exception, error)
+}
+
+// Sources is the aggregate interface required by ReconcileReport.
+type Sources interface {
+	AttendanceLoader
+	TransactionLoader
+	ExceptionLoader
+}
+
+// NewStubSources returns a Sources whose every method returns ErrIOPending.
+func NewStubSources() Sources { return stubSources{} }
+
+type stubSources struct{}
+
+func (stubSources) LoadAdults(_ context.Context) ([]reconcile.Member, []string, error) {
+	return nil, nil, ErrIOPending
+}
+
+func (stubSources) LoadTransactions(_ context.Context) ([]reconcile.Transaction, error) {
+	return nil, ErrIOPending
+}
+
+func (stubSources) LoadExceptions(_ context.Context) (map[reconcile.ExceptionKey]reconcile.Exception, error) {
+	return nil, ErrIOPending
+}

go/internal/services/membership/reconcile.go

@@ -0,0 +1,30 @@
+package membership
+
+import (
+	"context"
+	"io"
+
+	domreconcile "fuj-management/go/internal/domain/reconcile"
+)
+
+// ReconcileReport loads attendance, transactions, and exceptions via s, runs
+// the three-phase reconciliation, and writes the balance report to out.
+// Returns ErrIOPending until real loaders are injected in M4.
+func ReconcileReport(ctx context.Context, s Sources, defaultYear int, out io.Writer) error {
+	members, sortedMonths, err := s.LoadAdults(ctx)
+	if err != nil {
+		return err
+	}
+	txns, err := s.LoadTransactions(ctx)
+	if err != nil {
+		return err
+	}
+	exceptions, err := s.LoadExceptions(ctx)
+	if err != nil {
+		return err
+	}
+
+	result := domreconcile.Reconcile(members, sortedMonths, txns, exceptions, defaultYear)
+	printReconcileReport(out, result, sortedMonths)
+	return nil
+}

go/internal/services/membership/reconcile_test.go

@@ -0,0 +1,68 @@
+package membership
+
+import (
+	"bytes"
+	"context"
+	"fuj-management/go/internal/domain/reconcile"
+	"strings"
+	"testing"
+)
+
+type fakeSources struct {
+	members    []reconcile.Member
+	months     []string
+	txns       []reconcile.Transaction
+	exceptions map[reconcile.ExceptionKey]reconcile.Exception
+}
+
+func (f fakeSources) LoadAdults(_ context.Context) ([]reconcile.Member, []string, error) {
+	return f.members, f.months, nil
+}
+
+func (f fakeSources) LoadTransactions(_ context.Context) ([]reconcile.Transaction, error) {
+	return f.txns, nil
+}
+
+func (f fakeSources) LoadExceptions(_ context.Context) (map[reconcile.ExceptionKey]reconcile.Exception, error) {
+	return f.exceptions, nil
+}
+
+func TestReconcileReport(t *testing.T) {
+	t.Parallel()
+	s := fakeSources{
+		members: []reconcile.Member{
+			{Name: "Alice", Tier: "A", Fees: map[string]reconcile.FeeData{
+				"2026-04": {Expected: 700, Attendance: 3},
+			}},
+		},
+		months: []string{"2026-04"},
+		txns: []reconcile.Transaction{
+			{
+				Date: "2026-04-10", Amount: 700, Person: "Alice", Purpose: "2026-04",
+				Sender: "Alice Bank", Message: "fee",
+			},
+		},
+		exceptions: map[reconcile.ExceptionKey]reconcile.Exception{},
+	}
+
+	var buf bytes.Buffer
+	if err := ReconcileReport(context.Background(), s, 2026, &buf); err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	got := buf.String()
+	if !strings.Contains(got, "PAYMENT RECONCILIATION REPORT") {
+		t.Error("missing report header")
+	}
+	if !strings.Contains(got, "OK") {
+		t.Errorf("expected 'OK' for fully-paid Alice, got:\n%s", got)
+	}
+}
+
+func TestReconcileReportStubErrors(t *testing.T) {
+	t.Parallel()
+	var buf bytes.Buffer
+	err := ReconcileReport(context.Background(), NewStubSources(), 2026, &buf)
+	if err == nil {
+		t.Fatal("expected error from stub, got nil")
+	}
+}

go/internal/services/membership/stub_test.go

@@ -0,0 +1,27 @@
+package membership
+
+import (
+	"context"
+	"errors"
+	"testing"
+)
+
+func TestStubLoaderReturnsErrIOPending(t *testing.T) {
+	t.Parallel()
+	s := NewStubSources()
+
+	_, _, err := s.LoadAdults(context.Background())
+	if !errors.Is(err, ErrIOPending) {
+		t.Errorf("LoadAdults: want ErrIOPending, got %v", err)
+	}
+
+	_, err = s.LoadTransactions(context.Background())
+	if !errors.Is(err, ErrIOPending) {
+		t.Errorf("LoadTransactions: want ErrIOPending, got %v", err)
+	}
+
+	_, err = s.LoadExceptions(context.Background())
+	if !errors.Is(err, ErrIOPending) {
+		t.Errorf("LoadExceptions: want ErrIOPending, got %v", err)
+	}
+}