extracted error

Author: SUSTAPLE117

pointers/wallet.go

@@ -16,17 +16,18 @@ type Wallet struct {
 }
 
 func (w *Wallet) Deposit(amount Bitcoin) {
-	fmt.Printf("address of balance in Deposit is %v \n", &w.balance)
 	w.balance += amount
 }
 
 func (w *Wallet) Balance() Bitcoin {
 	return w.balance
 }
 
+var ErrInsufficientFunds = errors.New("cannot withdraw, insufficient funds")
+
 func (w *Wallet) Withdraw(amount Bitcoin) error {
 	if amount > w.balance {
-		return errors.New("cannot withdraw, insufficient funds")
+		return ErrInsufficientFunds
 	}
 	w.balance -= amount
 	return nil

pointers/wallet_test.go

@@ -15,13 +15,13 @@ func TestWallet(t *testing.T) {
 		}
 	}
 
-	assertError := func(t *testing.T, got error, want string) {
+	assertError := func(t *testing.T, got error, want error) {
 		t.Helper()
 		if got == nil {
 			t.Fatal("wanted an error but didn't get one")
 		}
 
-		if got.Error() != want {
+		if got != want {
 			t.Errorf("got %q, want %q", got, want)
 		}
 	}
@@ -43,6 +43,6 @@ func TestWallet(t *testing.T) {
 		err := wallet.Withdraw(Bitcoin(100))
 
 		assertBalance(t, wallet, Bitcoin(20))
-		assertError(t, err, "cannot withdraw, insufficient funds")
+		assertError(t, err, ErrInsufficientFunds)
 	})
 }