e2e: improve p2p mode selection (#6929)

The previous implemention of hybrid set testing, which was entirely my
own creation, was a bit peculiar, and I think this probably clears thins up.

The previous implementation had far fewer legacy nodes in hybrid
networks, *and* also for some reason that I can't quite explain,
caused a test case to fail.

test/e2e/generator/generate.go

@@ -127,18 +127,11 @@ func generateTestnet(r *rand.Rand, opt map[string]interface{}) (e2e.Manifest, er
 		TxSize:           int64(txSize.Choose(r).(int)),
 	}
 
-	var p2pNodeFactor int
-
-	switch opt["p2p"].(P2PMode) {
-	case NewP2PMode:
-		manifest.UseLegacyP2P = true
-	case LegacyP2PMode:
-		manifest.UseLegacyP2P = false
-	case HybridP2PMode:
-		manifest.UseLegacyP2P = true
-		p2pNodeFactor = 2
+	p2pMode := opt["p2p"].(P2PMode)
+	switch p2pMode {
+	case NewP2PMode, LegacyP2PMode, HybridP2PMode:
 	default:
-		return manifest, fmt.Errorf("unknown p2p mode %s", opt["p2p"])
+		return manifest, fmt.Errorf("unknown p2p mode %s", p2pMode)
 	}
 
 	var numSeeds, numValidators, numFulls, numLightClients int
@@ -161,10 +154,11 @@ func generateTestnet(r *rand.Rand, opt map[string]interface{}) (e2e.Manifest, er
 	for i := 1; i <= numSeeds; i++ {
 		node := generateNode(r, e2e.ModeSeed, 0, manifest.InitialHeight, false)
 
-		if p2pNodeFactor == 0 {
-			node.UseLegacyP2P = manifest.UseLegacyP2P
-		} else if p2pNodeFactor%i == 0 {
-			node.UseLegacyP2P = !manifest.UseLegacyP2P
+		switch p2pMode {
+		case LegacyP2PMode:
+			node.UseLegacyP2P = true
+		case HybridP2PMode:
+			node.UseLegacyP2P = r.Intn(2) == 1
 		}
 
 		manifest.Nodes[fmt.Sprintf("seed%02d", i)] = node
@@ -185,10 +179,11 @@ func generateTestnet(r *rand.Rand, opt map[string]interface{}) (e2e.Manifest, er
 		node := generateNode(
 			r, e2e.ModeValidator, startAt, manifest.InitialHeight, i <= 2)
 
-		if p2pNodeFactor == 0 {
-			node.UseLegacyP2P = manifest.UseLegacyP2P
-		} else if p2pNodeFactor%i == 0 {
-			node.UseLegacyP2P = !manifest.UseLegacyP2P
+		switch p2pMode {
+		case LegacyP2PMode:
+			node.UseLegacyP2P = true
+		case HybridP2PMode:
+			node.UseLegacyP2P = r.Intn(2) == 1
 		}
 
 		manifest.Nodes[name] = node
@@ -221,11 +216,13 @@ func generateTestnet(r *rand.Rand, opt map[string]interface{}) (e2e.Manifest, er
 		}
 		node := generateNode(r, e2e.ModeFull, startAt, manifest.InitialHeight, false)
 
-		if p2pNodeFactor == 0 {
-			node.UseLegacyP2P = manifest.UseLegacyP2P
-		} else if p2pNodeFactor%i == 0 {
-			node.UseLegacyP2P = !manifest.UseLegacyP2P
+		switch p2pMode {
+		case LegacyP2PMode:
+			node.UseLegacyP2P = true
+		case HybridP2PMode:
+			node.UseLegacyP2P = r.Intn(2) == 1
 		}
+
 		manifest.Nodes[fmt.Sprintf("full%02d", i)] = node
 	}
 

test/e2e/pkg/manifest.go

@@ -60,9 +60,6 @@ type Manifest struct {
 	// by individual nodes.
 	LogLevel string `toml:"log_level"`
 
-	// UseLegacyP2P uses the legacy p2p layer for all nodes in a test.
-	UseLegacyP2P bool `toml:"use_legacy_p2p"`
-
 	// QueueType describes the type of queue that the system uses internally
 	QueueType string `toml:"queue_type"`
 

test/e2e/pkg/testnet.go

@@ -182,7 +182,7 @@ func LoadTestnet(file string) (*Testnet, error) {
 			Perturbations:    []Perturbation{},
 			LogLevel:         manifest.LogLevel,
 			QueueType:        manifest.QueueType,
-			UseLegacyP2P:     manifest.UseLegacyP2P && nodeManifest.UseLegacyP2P,
+			UseLegacyP2P:     nodeManifest.UseLegacyP2P,
 		}
 
 		if node.StartAt == testnet.InitialHeight {