multi: move itest out of lntest

This commit moves all the test cases living in `itest` out of `lntest`,
further making `lntest` an independent package for general testing.

itest/lnd_wumbo_channels_test.go

@@ -0,0 +1,52 @@
+package itest
+
+import (
+	"github.com/btcsuite/btcd/btcutil"
+	"github.com/lightningnetwork/lnd/funding"
+	"github.com/lightningnetwork/lnd/lntemp"
+	"github.com/lightningnetwork/lnd/lnwallet"
+)
+
+// testWumboChannels tests that only a node that signals wumbo channel
+// acceptances will allow a wumbo channel to be created. Additionally, if a
+// node is running with mini channels only enabled, then they should reject any
+// inbound wumbo channel requests.
+func testWumboChannels(ht *lntemp.HarnessTest) {
+	// With all the channel types exercised, we'll now make sure the wumbo
+	// signalling support works properly.
+	//
+	// We'll make two new nodes, with one of them signalling support for
+	// wumbo channels while the other doesn't.
+	wumboNode := ht.NewNode("wumbo", []string{"--protocol.wumbo-channels"})
+	miniNode := ht.NewNode("mini", nil)
+
+	// We'll send coins to the wumbo node, as it'll be the one imitating
+	// the channel funding.
+	ht.FundCoins(btcutil.SatoshiPerBitcoin, wumboNode)
+
+	// Next we'll connect both nodes, then attempt to make a wumbo channel
+	// funding request to the mini node we created above. The wumbo request
+	// should fail as the node isn't advertising wumbo channels.
+	ht.EnsureConnected(wumboNode, miniNode)
+
+	chanAmt := funding.MaxBtcFundingAmount + 1
+	// The test should indicate a failure due to the channel being too
+	// large.
+	ht.OpenChannelAssertErr(
+		wumboNode, miniNode, lntemp.OpenChannelParams{Amt: chanAmt},
+		lnwallet.ErrChanTooLarge(chanAmt, funding.MaxBtcFundingAmount),
+	)
+
+	// We'll now make another wumbo node to accept our wumbo channel
+	// funding.
+	wumboNode2 := ht.NewNode(
+		"wumbo2", []string{"--protocol.wumbo-channels"},
+	)
+
+	// Creating a wumbo channel between these two nodes should succeed.
+	ht.EnsureConnected(wumboNode, wumboNode2)
+	chanPoint := ht.OpenChannel(
+		wumboNode, wumboNode2, lntemp.OpenChannelParams{Amt: chanAmt},
+	)
+	ht.CloseChannel(wumboNode, chanPoint)
+}