htlcswitch: add heldHtlcSet

Isolation of the set logic so that it will be easier to add watchdog functionality later.

htlcswitch/held_htlc_set_test.go

@@ -0,0 +1,80 @@
+package htlcswitch
+
+import (
+	"testing"
+
+	"github.com/lightningnetwork/lnd/channeldb"
+	"github.com/lightningnetwork/lnd/lnwire"
+	"github.com/stretchr/testify/require"
+)
+
+func TestHeldHtlcSetEmpty(t *testing.T) {
+	set := newHeldHtlcSet()
+
+	// Test operations on an empty set.
+	require.False(t, set.exists(channeldb.CircuitKey{}))
+
+	_, err := set.pop(channeldb.CircuitKey{})
+	require.Error(t, err)
+
+	set.popAll(
+		func(_ InterceptedForward) {
+			require.Fail(t, "unexpected fwd")
+		},
+	)
+}
+
+func TestHeldHtlcSet(t *testing.T) {
+	set := newHeldHtlcSet()
+
+	key := channeldb.CircuitKey{
+		ChanID: lnwire.NewShortChanIDFromInt(1),
+		HtlcID: 2,
+	}
+
+	// Test pushing a nil forward.
+	require.Error(t, set.push(key, nil))
+
+	// Test pushing a forward.
+	fwd := &interceptedForward{
+		htlc: &lnwire.UpdateAddHTLC{},
+	}
+	require.NoError(t, set.push(key, fwd))
+
+	// Re-pushing should fail.
+	require.Error(t, set.push(key, fwd))
+
+	// Test popping the fwd.
+	poppedFwd, err := set.pop(key)
+	require.NoError(t, err)
+	require.Equal(t, fwd, poppedFwd)
+
+	_, err = set.pop(key)
+	require.Error(t, err)
+
+	// Pushing the forward again.
+	require.NoError(t, set.push(key, fwd))
+
+	// Test for each.
+	var cbCalled bool
+	set.forEach(func(_ InterceptedForward) {
+		cbCalled = true
+
+		require.Equal(t, fwd, poppedFwd)
+	})
+	require.True(t, cbCalled)
+
+	// Test popping all forwards.
+	cbCalled = false
+	set.popAll(
+		func(_ InterceptedForward) {
+			cbCalled = true
+
+			require.Equal(t, fwd, poppedFwd)
+		},
+	)
+	require.True(t, cbCalled)
+
+	_, err = set.pop(key)
+	require.Error(t, err)
+}