types: add Abs() method to sdk.Int (#8963)

Fixes #8962

Co-authored-by: Alessio Treglia <alessio@tendermint.com>

types/int.go

@@ -37,6 +37,8 @@ func mod(i *big.Int, i2 *big.Int) *big.Int { return new(big.Int).Mod(i, i2) }
 
 func neg(i *big.Int) *big.Int { return new(big.Int).Neg(i) }
 
+func abs(i *big.Int) *big.Int { return new(big.Int).Abs(i) }
+
 func min(i *big.Int, i2 *big.Int) *big.Int {
 	if i.Cmp(i2) == 1 {
 		return new(big.Int).Set(i2)
@@ -304,6 +306,11 @@ func (i Int) Neg() (res Int) {
 	return Int{neg(i.i)}
 }
 
+// Abs returns the absolute value of Int.
+func (i Int) Abs() Int {
+	return Int{abs(i.i)}
+}
+
 // return the minimum of the ints
 func MinInt(i1, i2 Int) Int {
 	return Int{min(i1.BigInt(), i2.BigInt())}

types/int_test.go

@@ -159,6 +159,8 @@ func (s *intTestSuite) TestArithInt() {
 			{sdk.MinInt(i1, i2), minint(n1, n2)},
 			{sdk.MaxInt(i1, i2), maxint(n1, n2)},
 			{i1.Neg(), -n1},
+			{i1.Abs(), n1},
+			{i1.Neg().Abs(), n1},
 		}
 
 		for tcnum, tc := range cases {
@@ -206,6 +208,7 @@ func (s *intTestSuite) TestImmutabilityAllInt() {
 		func(i *sdk.Int) { _ = i.MulRaw(rand.Int63()) },
 		func(i *sdk.Int) { _ = i.QuoRaw(rand.Int63()) },
 		func(i *sdk.Int) { _ = i.Neg() },
+		func(i *sdk.Int) { _ = i.Abs() },
 		func(i *sdk.Int) { _ = i.IsZero() },
 		func(i *sdk.Int) { _ = i.Sign() },
 		func(i *sdk.Int) { _ = i.Equal(randint()) },