feat: update wei to sat conversion

internal/entities/wei.go

@@ -63,7 +63,14 @@ func (w *Wei) ToRbtc() *big.Float {
 }
 
 func (w *Wei) ToSatoshi() *big.Float {
-	return new(big.Float).Quo(new(big.Float).SetInt(w.AsBigInt()), new(big.Float).SetInt(bTenPowTen))
+	remainder := new(big.Int)
+	quotient := new(big.Int)
+	quotient.QuoRem(w.AsBigInt(), bTenPowTen, remainder)
+	if remainder.Cmp(big.NewInt(0)) == 0 {
+		return new(big.Float).SetInt(quotient)
+	}
+	quotient.Add(quotient, big.NewInt(1))
+	return new(big.Float).SetInt(quotient)
 }
 
 func (w *Wei) String() string {

internal/entities/wei_test.go

@@ -162,7 +162,22 @@ func TestWei_ToSatoshi(t *testing.T) {
 		{
 			name: "1 wei to sat",
 			w:    entities.NewWei(1),
-			want: new(big.Float).Quo(new(big.Float).SetInt64(1), new(big.Float).SetInt(new(big.Int).Exp(big.NewInt(10), big.NewInt(10), nil))),
+			want: big.NewFloat(1),
+		},
+		{
+			name: "72160329123080000 wei to 7216033 sat",
+			w:    entities.NewWei(72160329123080000),
+			want: big.NewFloat(7216033),
+		},
+		{
+			name: "4360000000000000 wei to 436000 sat",
+			w:    entities.NewWei(4360000000000000),
+			want: big.NewFloat(436000),
+		},
+		{
+			name: "1 RBTC to 100000000 sat",
+			w:    entities.NewWei(1000000000000000000),
+			want: big.NewFloat(100000000),
 		},
 	}
 	for _, tt := range tests {