multi: context.Background() -> t.Context()

Use the new feature of Go 1.24, fix linter warnings.

This change was produced by:
 - running golangci-lint run --fix
 - sed 's/context.Background/t.Context/' -i `git grep -l context.Background | grep test.go`
 - manually fixing broken tests
 - itest, lntest: use ht.Context() where ht or hn is available
 - in HarnessNode.Stop() we keep using context.Background(), because it is
   called from a cleanup handler in which t.Context() is canceled already.

graph/builder_test.go

@@ -2,7 +2,6 @@ package graph
 
 import (
 	"bytes"
-	"context"
 	"crypto/sha256"
 	"encoding/hex"
 	"encoding/json"
@@ -44,7 +43,7 @@ const (
 // info was added to the database.
 func TestAddProof(t *testing.T) {
 	t.Parallel()
-	ctxb := context.Background()
+	ctxb := t.Context()
 
 	ctx := createTestCtxSingleNode(t, 0)
 
@@ -109,7 +108,7 @@ func TestIgnoreNodeAnnouncement(t *testing.T) {
 	}
 	copy(node.PubKeyBytes[:], pub.SerializeCompressed())
 
-	err := ctx.builder.AddNode(context.Background(), node)
+	err := ctx.builder.AddNode(t.Context(), node)
 	if !IsError(err, ErrIgnored) {
 		t.Fatalf("expected to get ErrIgnore, instead got: %v", err)
 	}
@@ -119,7 +118,7 @@ func TestIgnoreNodeAnnouncement(t *testing.T) {
 // ignore a channel policy for a channel not in the graph.
 func TestIgnoreChannelEdgePolicyForUnknownChannel(t *testing.T) {
 	t.Parallel()
-	ctxb := context.Background()
+	ctxb := t.Context()
 
 	const startingBlockHeight = 101
 
@@ -194,7 +193,7 @@ func TestIgnoreChannelEdgePolicyForUnknownChannel(t *testing.T) {
 // confirmed on the stale chain, and resync to the main chain.
 func TestWakeUpOnStaleBranch(t *testing.T) {
 	t.Parallel()
-	ctxb := context.Background()
+	ctxb := t.Context()
 
 	const startingBlockHeight = 101
 	ctx := createTestCtxSingleNode(t, startingBlockHeight)
@@ -354,7 +353,7 @@ func TestWakeUpOnStaleBranch(t *testing.T) {
 	// Give time to process new blocks.
 	time.Sleep(time.Millisecond * 500)
 
-	selfNode, err := ctx.graph.SourceNode(context.Background())
+	selfNode, err := ctx.graph.SourceNode(t.Context())
 	require.NoError(t, err)
 
 	// Create new router with same graph database.
@@ -408,7 +407,7 @@ func TestWakeUpOnStaleBranch(t *testing.T) {
 // it is active.
 func TestDisconnectedBlocks(t *testing.T) {
 	t.Parallel()
-	ctxb := context.Background()
+	ctxb := t.Context()
 
 	const startingBlockHeight = 101
 	ctx := createTestCtxSingleNode(t, startingBlockHeight)
@@ -609,7 +608,7 @@ func TestDisconnectedBlocks(t *testing.T) {
 // ChannelRouter, then the channels are properly pruned.
 func TestChansClosedOfflinePruneGraph(t *testing.T) {
 	t.Parallel()
-	ctxb := context.Background()
+	ctxb := t.Context()
 
 	const startingBlockHeight = 101
 	ctx := createTestCtxSingleNode(t, startingBlockHeight)
@@ -1037,7 +1036,7 @@ func testPruneChannelGraphDoubleDisabled(t *testing.T, assumeValid bool) {
 // node announcements.
 func TestIsStaleNode(t *testing.T) {
 	t.Parallel()
-	ctxb := context.Background()
+	ctxb := t.Context()
 
 	const startingBlockHeight = 101
 	ctx := createTestCtxSingleNode(t, startingBlockHeight)
@@ -1095,7 +1094,7 @@ func TestIsStaleNode(t *testing.T) {
 		Features:             testFeatures,
 	}
 	copy(n1.PubKeyBytes[:], priv1.PubKey().SerializeCompressed())
-	if err := ctx.builder.AddNode(context.Background(), n1); err != nil {
+	if err := ctx.builder.AddNode(t.Context(), n1); err != nil {
 		t.Fatalf("could not add node: %v", err)
 	}
 
@@ -1117,7 +1116,7 @@ func TestIsStaleNode(t *testing.T) {
 // channel announcements.
 func TestIsKnownEdge(t *testing.T) {
 	t.Parallel()
-	ctxb := context.Background()
+	ctxb := t.Context()
 
 	const startingBlockHeight = 101
 	ctx := createTestCtxSingleNode(t, startingBlockHeight)
@@ -1167,7 +1166,7 @@ func TestIsKnownEdge(t *testing.T) {
 // stale channel edge update announcements.
 func TestIsStaleEdgePolicy(t *testing.T) {
 	t.Parallel()
-	ctxb := context.Background()
+	ctxb := t.Context()
 
 	const startingBlockHeight = 101
 	ctx := createTestCtxFromFile(t, startingBlockHeight, basicGraphFilePath)
@@ -1359,7 +1358,7 @@ func createTestCtxFromFile(t *testing.T,
 func parseTestGraph(t *testing.T, useCache bool, path string) (
 	*testGraphInstance, error) {
 
-	ctx := context.Background()
+	ctx := t.Context()
 
 	graphJSON, err := os.ReadFile(path)
 	if err != nil {
@@ -1751,7 +1750,7 @@ func createTestGraphFromChannels(t *testing.T, useCache bool,
 	testChannels []*testChannel, source string) (*testGraphInstance,
 	error) {
 
-	ctx := context.Background()
+	ctx := t.Context()
 
 	// We'll use this fake address for the IP address of all the nodes in
 	// our tests. This value isn't needed for path finding so it doesn't