firewalldb: return consistent errors for priv map tests

In preparation for adding a different implementation of the privacy
mapper DB, we make sure that the unit tests are expecting consistent
errors.

Author: ellemouton

firewalldb/privacy_mapper.go

@@ -5,6 +5,7 @@ import (
 	"crypto/rand"
 	"encoding/binary"
 	"encoding/hex"
+	"errors"
 	"fmt"
 	"math/big"
 	"strconv"
@@ -14,6 +15,20 @@ import (
 	"github.com/lightninglabs/lightning-terminal/session"
 )
 
+var (
+	// ErrDuplicateRealValue is returned when an attempt is made to insert
+	// a new real-pseudo pair into the db, but the real value already exists
+	// in the db.
+	ErrDuplicateRealValue = errors.New("an entry with the given real " +
+		"value already exists")
+
+	// ErrDuplicatePseudoValue is returned when an attempt is made to
+	// insert a new real-pseudo pair into the db, but the pseudo value
+	// already exists in the db.
+	ErrDuplicatePseudoValue = errors.New("an entry with the given pseudo " +
+		"value already exists")
+)
+
 // NewPrivacyMapDB is a function type that takes a group ID and uses it to
 // construct a new PrivacyMapDB.
 type NewPrivacyMapDB func(groupID session.ID) PrivacyMapDB

firewalldb/privacy_mapper_kvdb.go

@@ -77,13 +77,12 @@ func (p *privacyMapTx) NewPair(_ context.Context, real, pseudo string) error {
 	}
 
 	if len(realToPseudoBucket.Get([]byte(real))) != 0 {
-		return fmt.Errorf("an entry already exists for real "+
-			"value: %x", real)
+		return fmt.Errorf("%w, real: %v", ErrDuplicateRealValue, real)
 	}
 
 	if len(pseudoToRealBucket.Get([]byte(pseudo))) != 0 {
-		return fmt.Errorf("an entry already exists for pseudo "+
-			"value: %x", pseudo)
+		return fmt.Errorf("%w, pseudo: %v", ErrDuplicatePseudoValue,
+			pseudo)
 	}
 
 	err = realToPseudoBucket.Put([]byte(real), []byte(pseudo))

firewalldb/privacy_mapper_test.go

@@ -96,14 +96,12 @@ func TestPrivacyMapStorage(t *testing.T) {
 		// Try to add a new pair that has the same real value as the
 		// first pair. This should fail.
 		err = tx.NewPair(ctx, "real 1", "pseudo 2")
-		require.ErrorContains(t, err, "an entry already exists for "+
-			"real value")
+		require.ErrorIs(t, err, ErrDuplicateRealValue)
 
 		// Try to add a new pair that has the same pseudo value as the
 		// first pair. This should fail.
 		err = tx.NewPair(ctx, "real 2", "pseudo 1")
-		require.ErrorContains(t, err, "an entry already exists for "+
-			"pseudo value")
+		require.ErrorIs(t, err, ErrDuplicatePseudoValue)
 
 		// Add a few more pairs.
 		err = tx.NewPair(ctx, "real 2", "pseudo 2")