fixup Move networks to .testnetctl/networks

As per a comment from dasconnor, this supports storing non-network
data in the .testnetctl path in the future.

Author: maru-ava

tests/e2e/README.md

@@ -54,11 +54,11 @@ $ scripts/build_testnetctl.sh
 # Start a new network
 $ ./build/testnetctl start-network --avalanchego-path=/path/to/avalanchego
 ...
-Started network 1337 @ /home/me/.testnetctl/1337-20230705-213938-1707053131
+Started network 1337 @ /home/me/.testnetctl/networks/1337-20230705-213938-1707053131
 
 Configure testnetctl to target this network by default with one of the following statements:
- - source /home/me/.testnetctl/1337-20230705-213938-1707053131/network.env
- - export TESTNETCTL_NETWORK_DIR=/home/me/.testnetctl/1337-20230705-213938-1707053131
+ - source /home/me/.testnetctl/networks/1337-20230705-213938-1707053131/network.env
+ - export TESTNETCTL_NETWORK_DIR=/home/me/.testnetctl/networks/1337-20230705-213938-1707053131
 
 # Start a new test run to use the persistent network
 ginkgo -v ./tests/e2e -- \

tests/fixture/testnet/config.go

@@ -80,7 +80,7 @@ func (c *NetworkConfig) PopulateNetworkConfig(networkID uint32, validatorIDs []i
 			// - Randomly generate the network id (making sure it isn't a reserved ID)
 			// - Use only the network id (without a datetime suffix) on the filesystem
 			// - Support referring to a network by just the id against a default path
-			//   - e.g. ~/.testnetctl/[network id]
+			//   - e.g. ~/.testnetctl/networks/[network id]
 			networkID = uint32(1337)
 		}
 

tests/fixture/testnet/local/README.md

@@ -40,11 +40,11 @@ $ scripts/build_testnetctl.sh
 # Start a new network
 $ ./build/testnetctl start-network --avalanchego-path=/path/to/avalanchego
 ...
-Started network 1337 @ /home/me/.testnetctl/1337-20230705-213938-1707053131
+Started network 1337 @ /home/me/.testnetctl/networks/1337-20230705-213938-1707053131
 
 Configure testnetctl to target this network by default with one of the following statements:
- - source /home/me/.testnetctl/1337-20230705-213938-1707053131/network.env
- - export TESTNETCTL_NETWORK_DIR=/home/me/.testnetctl/1337-20230705-213938-1707053131
+ - source /home/me/.testnetctl/networks/1337-20230705-213938-1707053131/network.env
+ - export TESTNETCTL_NETWORK_DIR=/home/me/.testnetctl/networks/1337-20230705-213938-1707053131
 
 # Stop the network
 $ ./build/testnetctl stop-network --network-dir=/path/to/network
@@ -121,25 +121,26 @@ A local network relies on configuration written to disk in the following structu
 
 ```
 HOME
-└── .testnetctl                                           // Default parent directory for local networks
-    └── 1337-20230630-203525-2336789419              // Network path with form [network-id]-[timestamp]
-        ├── NodeID-37E8UK3x2YFsHE3RdALmfWcppcZ1eTuj9 // The id of a node is the name of its data dir
-        │   ├── chainData
-        │   │   └── ...
-        │   ├── config.json            // Node flags
-        │   ├── db
-        │   │   └── ...
-        │   ├── logs
-        │   │   └── ...
-        │   ├── plugins
-        │   │   └── ...
-        │   └── runtime.json           // Node runtime state (bootstrap IP, API URI, PID)
-        ├── chains
-        │   └── C
-        │       └── cchain_config.json // C-Chain config for all nodes
-        ├── defaults.json              // Default flags and configuration for network
-        ├── genesis.json               // Genesis for all nodes
-        └── network.env                // Sets network dir env to simplify use of network
+└── .testnetctl                                          // Root path for tool
+    └── networks                                         // Default parent directory for local networks
+        └── 1337-20230630-203525-2336789419              // Network path with form [network-id]-[timestamp]
+            ├── NodeID-37E8UK3x2YFsHE3RdALmfWcppcZ1eTuj9 // The id of a node is the name of its data dir
+            │   ├── chainData
+            │   │   └── ...
+            │   ├── config.json                          // Node flags
+            │   ├── db
+            │   │   └── ...
+            │   ├── logs
+            │   │   └── ...
+            │   ├── plugins
+            │   │   └── ...
+            │   └── runtime.json                         // Node runtime state (bootstrap IP, API URI, PID)
+            ├── chains
+            │   └── C
+            │       └── cchain_config.json               // C-Chain config for all nodes
+            ├── defaults.json                            // Default flags and configuration for network
+            ├── genesis.json                             // Genesis for all nodes
+            └── network.env                              // Sets network dir env to simplify use of network
 
 ```
 

tests/fixture/testnet/local/network.go

@@ -26,7 +26,7 @@ func GetDefaultRootDir() (string, error) {
 	if err != nil {
 		return "", err
 	}
-	return filepath.Join(homeDir, ".testnetctl"), nil
+	return filepath.Join(homeDir, ".testnetctl", "networks"), nil
 }
 
 // Defines the configuration required for a local network (i.e. one composed of local processes).
@@ -199,6 +199,11 @@ func (ln *LocalNetwork) Create(rootDir string) error {
 			}
 		}
 
+		// Ensure the directory exists
+		if err := os.MkdirAll(rootDir, perms.ReadWriteExecute); err != nil {
+			return fmt.Errorf("failed to create root network dir: %w", err)
+		}
+
 		// Create the path for the network's configuration. Putting the runtime configuration of a
 		// local network at a common path enables management of that network without a daemon.
 		//