fix: Revert transactions (#441)

formancehq · Mar 29, 2023 · e088da1 · e088da1
1 parent cc9177b
commit e088da1
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Showing 2 changed files with 127 additions and 45 deletions.
diff --git a/pkg/core/posting.go b/pkg/core/posting.go
@@ -18,15 +18,12 @@ type Posting struct {
 type Postings []Posting
 
 func (ps Postings) Reverse() {
-	if len(ps) == 1 {
-		ps[0].Source, ps[0].Destination = ps[0].Destination, ps[0].Source
-		return
-	}
-	for i := len(ps)/2 - 1; i >= 0; i-- {
-		opp := len(ps) - 1 - i
-		ps[i], ps[opp] = ps[opp], ps[i]
+	for i := range ps {
 		ps[i].Source, ps[i].Destination = ps[i].Destination, ps[i].Source
-		ps[opp].Source, ps[opp].Destination = ps[opp].Destination, ps[opp].Source
+	}
+
+	for i := 0; i < len(ps)/2; i++ {
+		ps[i], ps[len(ps)-i-1] = ps[len(ps)-i-1], ps[i]
 	}
 }
 

diff --git a/pkg/core/transaction_test.go b/pkg/core/transaction_test.go
@@ -3,51 +3,136 @@ package core
 import (
 	"testing"
 
-	"github.com/google/go-cmp/cmp"
+	"github.com/stretchr/testify/require"
 )
 
 func TestReverseTransaction(t *testing.T) {
-	tx := &ExpandedTransaction{
-		Transaction: Transaction{
-			TransactionData: TransactionData{
-				Postings: Postings{
-					{
-						Source:      "world",
-						Destination: "users:001",
-						Amount:      NewMonetaryInt(100),
-						Asset:       "COIN",
+	t.Run("1 posting", func(t *testing.T) {
+		tx := &ExpandedTransaction{
+			Transaction: Transaction{
+				TransactionData: TransactionData{
+					Postings: Postings{
+						{
+							Source:      "world",
+							Destination: "users:001",
+							Amount:      NewMonetaryInt(100),
+							Asset:       "COIN",
+						},
 					},
-					{
-						Source:      "users:001",
-						Destination: "payments:001",
-						Amount:      NewMonetaryInt(100),
-						Asset:       "COIN",
+					Reference: "foo",
+				},
+			},
+		}
+
+		expected := TransactionData{
+			Postings: Postings{
+				{
+					Source:      "users:001",
+					Destination: "world",
+					Amount:      NewMonetaryInt(100),
+					Asset:       "COIN",
+				},
+			},
+			Reference: "revert_foo",
+		}
+		require.Equal(t, expected, tx.Reverse())
+	})
+
+	t.Run("2 postings", func(t *testing.T) {
+		tx := &ExpandedTransaction{
+			Transaction: Transaction{
+				TransactionData: TransactionData{
+					Postings: Postings{
+						{
+							Source:      "world",
+							Destination: "users:001",
+							Amount:      NewMonetaryInt(100),
+							Asset:       "COIN",
+						},
+						{
+							Source:      "users:001",
+							Destination: "payments:001",
+							Amount:      NewMonetaryInt(100),
+							Asset:       "COIN",
+						},
 					},
+					Reference: "foo",
 				},
-				Reference: "foo",
 			},
-		},
-	}
-
-	expected := TransactionData{
-		Postings: Postings{
-			{
-				Source:      "payments:001",
-				Destination: "users:001",
-				Amount:      NewMonetaryInt(100),
-				Asset:       "COIN",
+		}
+
+		expected := TransactionData{
+			Postings: Postings{
+				{
+					Source:      "payments:001",
+					Destination: "users:001",
+					Amount:      NewMonetaryInt(100),
+					Asset:       "COIN",
+				},
+				{
+					Source:      "users:001",
+					Destination: "world",
+					Amount:      NewMonetaryInt(100),
+					Asset:       "COIN",
+				},
 			},
-			{
-				Source:      "users:001",
-				Destination: "world",
-				Amount:      NewMonetaryInt(100),
-				Asset:       "COIN",
+			Reference: "revert_foo",
+		}
+		require.Equal(t, expected, tx.Reverse())
+	})
+
+	t.Run("3 postings", func(t *testing.T) {
+		tx := &ExpandedTransaction{
+			Transaction: Transaction{
+				TransactionData: TransactionData{
+					Postings: Postings{
+						{
+							Source:      "world",
+							Destination: "users:001",
+							Amount:      NewMonetaryInt(100),
+							Asset:       "COIN",
+						},
+						{
+							Source:      "users:001",
+							Destination: "payments:001",
+							Amount:      NewMonetaryInt(100),
+							Asset:       "COIN",
+						},
+						{
+							Source:      "payments:001",
+							Destination: "alice",
+							Amount:      NewMonetaryInt(100),
+							Asset:       "COIN",
+						},
+					},
+					Reference: "foo",
+				},
 			},
-		},
-		Reference: "revert_foo",
-	}
+		}
 
-	if diff := cmp.Diff(expected, tx.Reverse()); diff != "" {
-		t.Errorf("Reverse() mismatch (-want +got):\n%s", diff)
-	}
+		expected := TransactionData{
+			Postings: Postings{
+				{
+					Source:      "alice",
+					Destination: "payments:001",
+					Amount:      NewMonetaryInt(100),
+					Asset:       "COIN",
+				},
+				{
+					Source:      "payments:001",
+					Destination: "users:001",
+					Amount:      NewMonetaryInt(100),
+					Asset:       "COIN",
+				},
+				{
+					Source:      "users:001",
+					Destination: "world",
+					Amount:      NewMonetaryInt(100),
+					Asset:       "COIN",
+				},
+			},
+			Reference: "revert_foo",
+		}
+		require.Equal(t, expected, tx.Reverse())
+	})
 }