fix tvx init.

cmd/tvx/extract.go

@@ -49,6 +49,8 @@ var extractCmd = &cli.Command{
 	Name:        "extract",
 	Description: "generate a test vector by extracting it from a live chain",
 	Action:      runExtract,
+	Before:      initialize,
+	After:       destroy,
 	Flags: []cli.Flag{
 		&repoFlag,
 		&cli.StringFlag{

cmd/tvx/extract_many.go

@@ -43,6 +43,8 @@ var extractManyCmd = &cli.Command{
    after these compulsory seven.
 `,
 	Action: runExtractMany,
+	Before: initialize,
+	After:  destroy,
 	Flags: []cli.Flag{
 		&repoFlag,
 		&cli.StringFlag{

cmd/tvx/main.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"fmt"
 	"log"
 	"os"
 	"sort"
@@ -47,11 +48,6 @@ func main() {
    tvx extract-many performs a batch extraction of many messages, supplied in a
    CSV file. Refer to the help of that subcommand for more info.
 
-   tvx project projects an existing test vector against a different protocol
-   version, reporting the result, optionally appending a new variant to the
-   vector in place if deemed equivalent, or producing a new vector if
-   non-equivalent.
-
    tvx simulate takes a raw message and simulates it on top of the supplied
    epoch, reporting the result on stderr and writing a test vector on stdout
    or into the specified file.
@@ -80,8 +76,6 @@ func main() {
 			extractManyCmd,
 			simulateCmd,
 		},
-		Before: initialize,
-		After:  destroy,
 	}
 
 	sort.Sort(cli.CommandsByName(app.Commands))
@@ -107,7 +101,9 @@ func initialize(c *cli.Context) error {
 
 	// Make the API client.
 	var err error
-	FullAPI, Closer, err = lcli.GetFullNodeAPI(c)
+	if FullAPI, Closer, err = lcli.GetFullNodeAPI(c); err != nil {
+		err = fmt.Errorf("failed to locate Lotus node; ")
+	}
 	return err
 }
 

cmd/tvx/simulate.go

@@ -29,15 +29,19 @@ var simulateFlags struct {
 
 var simulateCmd = &cli.Command{
 	Name: "simulate",
-	Description: "simulate a raw message on top of the supplied" +
+	Description: "simulate a raw message on top of the supplied epoch (or HEAD), " +
-		"epoch, reporting the result on stderr and writing a test vector on stdout" +
+		"reporting the result on stderr and writing a test vector on stdout " +
 		"or into the specified file",
 	Action: runSimulateCmd,
+	Before: initialize,
+	After:  destroy,
 	Flags: []cli.Flag{
+		&repoFlag,
 		&cli.StringFlag{
 			Name:        "msg",
 			Usage:       "base64 cbor-encoded message",
 			Destination: &simulateFlags.msg,
+			Required:    true,
 		},
 		&cli.Int64Flag{
 			Name:        "at-epoch",