*: replace test usages of context.TODO() with context.Background()

This commit replaces all usages of context.TODO() with context.Background()
in tests, and adds a lint rule ensuring context.TODO() does not appear.
Tests should always be initiating a new context if they are calling a
function for the first time - it is now "unknown" and hence not a "TODO"
application.

Release note: None

pkg/base/node_id_test.go

@@ -30,7 +30,7 @@ func TestNodeIDContainer(t *testing.T) {
 	}
 
 	for i := 0; i < 2; i++ {
-		n.Set(context.TODO(), 5)
+		n.Set(context.Background(), 5)
 		if val := n.Get(); val != 5 {
 			t.Errorf("value should be 5, not %d", val)
 		}

pkg/bench/bench_test.go

@@ -884,7 +884,7 @@ CREATE TABLE bench.insert_distinct (
 						fmt.Fprintf(&buf, "(%d, %d)", zipf.Uint64(), n)
 					}
 
-					if _, err := db.DB.ExecContext(context.TODO(), buf.String()); err != nil {
+					if _, err := db.DB.ExecContext(context.Background(), buf.String()); err != nil {
 						return err
 					}
 				}

pkg/bench/pgbench_test.go

@@ -109,7 +109,7 @@ func BenchmarkPgbenchExec(b *testing.B) {
 	defer log.Scope(b).Close(b)
 	b.Run("Cockroach", func(b *testing.B) {
 		s, _, _ := serverutils.StartServer(b, base.TestServerArgs{Insecure: true})
-		defer s.Stopper().Stop(context.TODO())
+		defer s.Stopper().Stop(context.Background())
 
 		pgURL, cleanupFn := sqlutils.PGUrl(
 			b, s.ServingSQLAddr(), "benchmarkCockroach", url.User(security.RootUser))

pkg/blobs/bench_test.go

@@ -62,7 +62,7 @@ func BenchmarkStreamingReadFile(b *testing.B) {
 	rpcContext.TestingAllowNamedRPCToAnonymousServer = true
 
 	factory := setUpService(b, rpcContext, localNodeID, remoteNodeID, localExternalDir, remoteExternalDir)
-	blobClient, err := factory(context.TODO(), remoteNodeID)
+	blobClient, err := factory(context.Background(), remoteNodeID)
 	if err != nil {
 		b.Fatal(err)
 	}
@@ -84,7 +84,7 @@ func benchmarkStreamingReadFile(b *testing.B, tc *benchmarkTestCase) {
 	b.ResetTimer()
 	b.SetBytes(tc.fileSize)
 	for i := 0; i < b.N; i++ {
-		reader, err := tc.blobClient.ReadFile(context.TODO(), tc.fileName)
+		reader, err := tc.blobClient.ReadFile(context.Background(), tc.fileName)
 		if err != nil {
 			b.Fatal(err)
 		}
@@ -113,7 +113,7 @@ func BenchmarkStreamingWriteFile(b *testing.B) {
 	rpcContext.TestingAllowNamedRPCToAnonymousServer = true
 
 	factory := setUpService(b, rpcContext, localNodeID, remoteNodeID, localExternalDir, remoteExternalDir)
-	blobClient, err := factory(context.TODO(), remoteNodeID)
+	blobClient, err := factory(context.Background(), remoteNodeID)
 	if err != nil {
 		b.Fatal(err)
 	}
@@ -134,7 +134,7 @@ func benchmarkStreamingWriteFile(b *testing.B, tc *benchmarkTestCase) {
 	b.ResetTimer()
 	b.SetBytes(tc.fileSize)
 	for i := 0; i < b.N; i++ {
-		err := tc.blobClient.WriteFile(context.TODO(), tc.fileName, bytes.NewReader(content))
+		err := tc.blobClient.WriteFile(context.Background(), tc.fileName, bytes.NewReader(content))
 		if err != nil {
 			b.Fatal(err)
 		}

pkg/blobs/client_test.go

@@ -41,7 +41,7 @@ func createTestResources(t testing.TB) (string, string, *stop.Stopper, func()) {
 	return localExternalDir, remoteExternalDir, stopper, func() {
 		cleanupFn()
 		cleanupFn2()
-		stopper.Stop(context.TODO())
+		stopper.Stop(context.Background())
 		leaktest.AfterTest(t)()
 	}
 }
@@ -173,7 +173,7 @@ func TestBlobClientReadFile(t *testing.T) {
 		},
 	} {
 		t.Run(tc.name, func(t *testing.T) {
-			ctx := context.TODO()
+			ctx := context.Background()
 			blobClient, err := blobClientFactory(ctx, tc.nodeID)
 			if err != nil {
 				t.Fatal(err)
@@ -244,7 +244,7 @@ func TestBlobClientWriteFile(t *testing.T) {
 		},
 	} {
 		t.Run(tc.name, func(t *testing.T) {
-			ctx := context.TODO()
+			ctx := context.Background()
 			blobClient, err := blobClientFactory(ctx, tc.nodeID)
 			if err != nil {
 				t.Fatal(err)
@@ -359,7 +359,7 @@ func TestBlobClientList(t *testing.T) {
 		},
 	} {
 		t.Run(tc.name, func(t *testing.T) {
-			ctx := context.TODO()
+			ctx := context.Background()
 			blobClient, err := blobClientFactory(ctx, tc.nodeID)
 			if err != nil {
 				t.Fatal(err)
@@ -441,7 +441,7 @@ func TestBlobClientDeleteFrom(t *testing.T) {
 		},
 	} {
 		t.Run(tc.name, func(t *testing.T) {
-			ctx := context.TODO()
+			ctx := context.Background()
 			blobClient, err := blobClientFactory(ctx, tc.nodeID)
 			if err != nil {
 				t.Fatal(err)
@@ -517,7 +517,7 @@ func TestBlobClientStat(t *testing.T) {
 		},
 	} {
 		t.Run(tc.name, func(t *testing.T) {
-			ctx := context.TODO()
+			ctx := context.Background()
 			blobClient, err := blobClientFactory(ctx, tc.nodeID)
 			if err != nil {
 				t.Fatal(err)

pkg/blobs/service_test.go

@@ -34,7 +34,7 @@ func TestBlobServiceList(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	ctx := context.TODO()
+	ctx := context.Background()
 
 	t.Run("list-correct-files", func(t *testing.T) {
 		resp, err := service.List(ctx, &blobspb.GlobRequest{
@@ -78,7 +78,7 @@ func TestBlobServiceDelete(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	ctx := context.TODO()
+	ctx := context.Background()
 
 	t.Run("delete-correct-file", func(t *testing.T) {
 		_, err := service.Delete(ctx, &blobspb.DeleteRequest{
@@ -127,7 +127,7 @@ func TestBlobServiceStat(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	ctx := context.TODO()
+	ctx := context.Background()
 
 	t.Run("get-correct-file-size", func(t *testing.T) {
 		resp, err := service.Stat(ctx, &blobspb.StatRequest{