e2e: add contexts and e2e generator tests (#9426)

test/e2e/pkg/manifest.go

@@ -124,8 +124,8 @@ type ManifestNode struct {
 	SnapshotInterval uint64 `toml:"snapshot_interval"`
 
 	// RetainBlocks specifies the number of recent blocks to retain. Defaults to
-	// 0, which retains all blocks. Must be greater that PersistInterval and
-	// SnapshotInterval.
+	// 0, which retains all blocks. Must be greater that PersistInterval,
+	// SnapshotInterval and EvidenceAgeHeight.
 	RetainBlocks uint64 `toml:"retain_blocks"`
 
 	// Perturb lists perturbations to apply to the node after it has been

test/e2e/pkg/testnet.go

@@ -105,6 +105,11 @@ func LoadTestnet(file string) (*Testnet, error) {
 	if err != nil {
 		return nil, err
 	}
+	return NewTestnetFromManifest(manifest, file)
+}
+
+// NewTestnetFromManifest creates and validates a testnet from a manifest
+func NewTestnetFromManifest(manifest Manifest, file string) (*Testnet, error) {
 	dir := strings.TrimSuffix(file, filepath.Ext(file))
 
 	// Set up resource generators. These must be deterministic.