test: ensure tests convert from BTC to SAT properly

This commit is a follow up to the prior commit which fixed a rounding
error bug in lnwallet. For uniformity, we also fix other occurrences in
the breach arbiter, as well as the integration tests.

breacharbiter_test.go

@@ -1255,7 +1255,11 @@ func createInitChannels(revocationWindow int) (*lnwallet.LightningChannel, *lnwa
 	bobKeyPriv, bobKeyPub := btcec.PrivKeyFromBytes(btcec.S256(),
 		bobsPrivKey)
 
-	channelCapacity := btcutil.Amount(10 * 1e8)
+	channelCapacity, err := btcutil.NewAmount(10)
+	if err != nil {
+		return nil, nil, nil, err
+	}
+
 	channelBal := channelCapacity / 2
 	aliceDustLimit := btcutil.Amount(200)
 	bobDustLimit := btcutil.Amount(1300)

lnd_test.go

@@ -1418,7 +1418,7 @@ func testChannelForceClosure(net *lntest.NetworkHarness, t *harnessTest) {
 		t.Fatalf("unable to get carol's balance: %v", err)
 	}
 
-	carolStartingBalance := btcutil.Amount(carolBalResp.ConfirmedBalance * 1e8)
+	carolStartingBalance := carolBalResp.ConfirmedBalance
 
 	ctxt, _ := context.WithTimeout(ctxb, timeout)
 	chanPoint := openChannelAndAssert(ctxt, t, net, net.Alice, carol,
@@ -1965,11 +1965,11 @@ func testChannelForceClosure(net *lntest.NetworkHarness, t *harnessTest) {
 	if err != nil {
 		t.Fatalf("unable to get carol's balance: %v", err)
 	}
-	carolExpectedBalance := carolStartingBalance + pushAmt
-	if btcutil.Amount(carolBalResp.ConfirmedBalance*1e8) < carolExpectedBalance {
+	carolExpectedBalance := btcutil.Amount(carolStartingBalance) + pushAmt
+	if btcutil.Amount(carolBalResp.ConfirmedBalance) < carolExpectedBalance {
 		t.Fatalf("carol's balance is incorrect: expected %v got %v",
 			carolExpectedBalance,
-			btcutil.Amount(carolBalResp.ConfirmedBalance*1e8))
+			carolBalResp.ConfirmedBalance)
 	}
 }