refactor: BigInt newtype has a working Set(), allowing UnmarshalJSON(…

…) to work properly

integration_test/spend_test.go

@@ -2,6 +2,7 @@ package integrationtest
 
 import (
 	"fmt"
+	"math/big"
 	"testing"
 
 	"github.com/aeternity/aepp-sdk-go/aeternity"
@@ -22,9 +23,10 @@ func TestSpendTx(t *testing.T) {
 	expected := new(big.Int)
 	bobState, err := node.APIGetAccount(bob.Address)
 	if err != nil {
-		expected.Set(amount.Int)
+		expected.Set(amount)
 	} else {
-		expected.Add(bobState.Balance.Int, amount.Int)
+		bS := big.Int(bobState.Balance)
+		expected.Add(&bS, amount)
 	}
 
 	ttl, nonce, err := node.GetTTLNonce(sender, aeternity.Config.Client.TTL)
@@ -50,8 +52,9 @@ func TestSpendTx(t *testing.T) {
 		}
 	}
 	delay(getBobsAccount)
+	b := big.Int(bobState.Balance)
 
-	if bobState.Balance.Cmp(expected.Int) != 0 {
+	if expected.Cmp(&b) != 0 {
 		t.Fatalf("Bob should have %v, but has %v instead", expected.String(), bobState.Balance.String())
 	}
 }

utils/utils.go

@@ -136,6 +136,7 @@ func AskPassword(question string) (password string, err error) {
 }
 
 // BigInt is an alias for math/big.Int, for use with Swagger generated code.
+// Even though it has some corresponding methods, convert it as soon as possible into big.Int.
 type BigInt big.Int
 
 // String casts BigInt into big.Int and uses its String method.
@@ -178,8 +179,27 @@ func (b *BigInt) LargerOrEqualToZero() bool {
 
 // UnmarshalJSON casts BigInt into big.Int and uses its UnmarshalJSON method.
 func (b *BigInt) UnmarshalJSON(text []byte) error {
-	bc := big.Int(*b)
-	return bc.UnmarshalJSON(text)
+	bc := new(big.Int)
+	err := bc.UnmarshalJSON(text)
+	if err != nil {
+		return err
+	}
+	b.Set(bc)
+	return nil
+}
+
+// Set makes a BigInt equal to a given big.Int.
+func (b *BigInt) Set(i *big.Int) *BigInt {
+	iB := BigInt(*i)
+	*b = iB
+	return b
+}
+
+// Cmp compares two BigInts just like big.Int
+func (b *BigInt) Cmp(i *BigInt) int {
+	b2 := big.Int(*b)
+	i2 := big.Int(*i)
+	return b2.Cmp(&i2)
 }
 
 // NewBigIntFromString returns a new math/big.Int from a string representation

utils/utils_test.go

@@ -70,3 +70,31 @@ func TestBigIntLargerThanZero(t *testing.T) {
 		}
 	}
 }
+
+func TestBigInt_UnmarshalJSON(t *testing.T) {
+	type args struct {
+		text []byte
+	}
+	tests := []struct {
+		name    string
+		b       BigInt
+		args    args
+		wantErr bool
+	}{{
+		name:    "Deserialize this",
+		args:    args{[]byte("1600000000000000000129127208515966861305")},
+		b:       BigInt(*RequireBigIntFromString("1600000000000000000129127208515966861305")),
+		wantErr: false,
+	}}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			b := &BigInt{}
+			if err := b.UnmarshalJSON(tt.args.text); (err != nil) != tt.wantErr {
+				t.Errorf("BigInt.UnmarshalJSON() error = %v, wantErr %v", err, tt.wantErr)
+			}
+			if b.Cmp(&tt.b) != 0 {
+				t.Errorf("The values are not the same: b: %s, want: %s", b.String(), tt.b.String())
+			}
+		})
+	}
+}