add comments

nodebuilder/tests/fraud_test.go

@@ -112,7 +112,6 @@ func TestFraudProofHandling(t *testing.T) {
 	getCancel()
 
 	require.NoError(t, err)
-	require.NotNil(t, proofs)
 	require.Len(t, proofs, 1)
 	require.True(t, proofs[0].Type() == byzantine.BadEncoding)
 	// This is an obscure way to check if the Syncer was stopped.
@@ -121,8 +120,16 @@ func TestFraudProofHandling(t *testing.T) {
 	//  lifecycles of each Module.
 	// 6.
 	attempts := 0
-	timeOut := blockTime * 5
+	// random height after befp.height
 	height := uint64(15)
+	// initial timeout is set to 5 sec, as we are targeting the height=15,
+	// blockTime=1 sec, expected befp height=10
+	timeOut := blockTime * 5
+
+	// during befp validation the node can still receive headers and it mostly depends on
+	// the operating system or hardware(e.g. on macOS tests is working 100% time with a single height=15,
+	// and on the Linux VM sometimes the last height is 17-18). So, lets give a chance for our befp validator to check
+	// the fraud proof and stop the syncer.
 	for attempts < 5 {
 		syncCtx, syncCancel := context.WithTimeout(context.Background(), timeOut)
 		_, err = full.HeaderServ.WaitForHeight(syncCtx, height)
@@ -134,9 +141,8 @@ func TestFraudProofHandling(t *testing.T) {
 		timeOut = blockTime
 		height++
 	}
-
-	require.NotNil(t, err)
 	require.ErrorIs(t, err, context.DeadlineExceeded)
+
 	// 7.
 	cfg = nodebuilder.DefaultConfig(node.Light)
 	cfg.Header.TrustedPeers = append(cfg.Header.TrustedPeers, addrs[0].String())