package wallet

import "testing"

func TestWallet(t *testing.T) {
  assertBalance := func(t testing.TB, wallet Wallet, want Bitcoin) {
    t.Helper()
    got := wallet.Balance()

    if got != want {
      t.Errorf("got %s want %s", got, want)
    }
  }

  assertNoError := func(t testing.TB, got error) {
    t.Helper()
    if got != nil {
      t.Fatal("got an error but didn't want one")
    }
  }

  assertError := func(t testing.TB, got, want error) {
    t.Helper()
    if got == nil {
      t.Fatal("wanted an error but didn't get one")
    }

    if got != want {
      t.Errorf("got %q, want %q", got, want)
    }
  }

  t.Run("deposit", func(t *testing.T) {
    wallet := Wallet{}
    wallet.Deposit(Bitcoin(10))
    assertBalance(t, wallet, Bitcoin(10))
  })
  t.Run("withdraw with funds", func(t *testing.T) {
    wallet := Wallet{balance: Bitcoin(20)}
    err := wallet.Withdraw(Bitcoin(10))
    assertNoError(t, err)
    assertBalance(t, wallet, Bitcoin(10))
  })
  t.Run("withdraw insufficient funds", func(t *testing.T) {
    startingBalance := Bitcoin(20)
    wallet := Wallet{startingBalance}
    err := wallet.Withdraw(Bitcoin(100))
    assertError(t, err, ErrInsufficientFunds)
    assertBalance(t, wallet, startingBalance)
  })
}