Distinguish debit and credit postings sharing an upstream reference

2026-09-10 15:48:42 +02:00
parent 964b9dfc15
commit bec6d0b444
3 changed files with 119 additions and 8 deletions
@@ -105,6 +105,104 @@ func TestUpstreamIdentityPreferredAndAccountScoped(t *testing.T) {
 		t.Fatal("changed immutable upstream money accepted")
 	}
 }
+func TestUpstreamReferenceSeparatesDebitAndCredit(t *testing.T) {
+	d := fixtureDataset()
+	debit := fixtureFacts()
+	debit.Source = "enablebanking"
+	debit.ExternalID = "shared-bank-reference"
+	credit := debit
+	credit.Amount = "12.30"
+	rows, err := NormalizeAndDedupe(d, []domain.Facts{debit, credit, debit, credit})
+	if err != nil {
+		t.Fatal(err)
+	}
+	amounts := map[domain.Money]int{}
+	for _, row := range rows {
+		amounts[row.Facts.Amount]++
+	}
+	if !reflect.DeepEqual(amounts, map[domain.Money]int{"-12.30": 1, "12.30": 1}) {
+		t.Fatalf("debit/credit postings lost or duplicated: %+v", rows)
+	}
+	d.Transactions = rows
+	if err := domain.Validate(d); err != nil {
+		t.Fatal(err)
+	}
+	again, err := NormalizeAndDedupe(d, []domain.Facts{credit, debit})
+	if err != nil || len(again) != 0 {
+		t.Fatalf("repeated debit/credit pair was not idempotent: %+v %v", again, err)
+	}
+}
+
+func TestUpstreamDirectionPreservesPreviouslyStoredIdentity(t *testing.T) {
+	for _, amount := range []domain.Money{"-12.30", "12.30"} {
+		t.Run(string(amount), func(t *testing.T) {
+			d := fixtureDataset()
+			stored := fixtureFacts()
+			stored.Source = "enablebanking"
+			stored.ExternalID = "shared-bank-reference"
+			stored.Amount = amount
+			// Reproduce the journal identity written before direction scoping.
+			stored.ID = "tx_" + digest(stored.AccountID, stored.Source, stored.ExternalID)
+			stored.Fingerprint = fingerprint(stored)
+			d.Transactions = []domain.Transaction{{Facts: stored, Enrichment: domain.Fallback(stored)}}
+			opposite := stored
+			opposite.Amount = "12.30"
+			if amount == "12.30" {
+				opposite.Amount = "-12.30"
+			}
+			incoming := stored
+			incoming.RawDescription = "Updated upstream display"
+			added, err := NormalizeAndDedupe(d, []domain.Facts{opposite, incoming})
+			if err != nil || len(added) != 1 || added[0].Facts.Amount != opposite.Amount {
+				t.Fatalf("stored posting duplicated or opposite posting lost: %+v %v", added, err)
+			}
+			if !reflect.DeepEqual(d.Transactions[0].Facts, stored) {
+				t.Fatal("previously stored bank facts were rewritten")
+			}
+			d.Transactions = append(d.Transactions, added...)
+			if err := domain.Validate(d); err != nil {
+				t.Fatal(err)
+			}
+			again, err := NormalizeAndDedupe(d, []domain.Facts{incoming, opposite})
+			if err != nil || len(again) != 0 {
+				t.Fatalf("upgraded journal was not idempotent: %+v %v", again, err)
+			}
+		})
+	}
+}
+
+func TestUpstreamReferenceRejectsSameDirectionConflicts(t *testing.T) {
+	original := fixtureFacts()
+	original.Source = "enablebanking"
+	original.ExternalID = "shared-bank-reference"
+	original.Amount = "12.30"
+	for _, tc := range []struct {
+		name   string
+		change func(*domain.Facts)
+	}{
+		{"amount", func(f *domain.Facts) { f.Amount = "99.00" }},
+		{"booking date", func(f *domain.Facts) { f.BookingDate = "2026-09-02" }},
+		{"currency", func(f *domain.Facts) { f.Currency = "USD" }},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			d := fixtureDataset()
+			changed := original
+			tc.change(&changed)
+			if added, err := NormalizeAndDedupe(d, []domain.Facts{original, changed}); err == nil || added != nil {
+				t.Fatal("conflicting incoming postings were accepted")
+			}
+			var err error
+			d.Transactions, err = NormalizeAndDedupe(d, []domain.Facts{original})
+			if err != nil {
+				t.Fatal(err)
+			}
+			if added, err := NormalizeAndDedupe(d, []domain.Facts{changed}); err == nil || added != nil {
+				t.Fatal("changed stored booking facts were accepted")
+			}
+		})
+	}
+}
+
 func TestDistinctUpstreamIDsPreserveEqualTransactions(t *testing.T) {
 	d := fixtureDataset()
 	a := fixtureFacts()