actually yield checksums to caller

While fixing a bug that log messages were ending up
in the output buffer for backups, we fixed up a bunch of
things to do with log messages and output for various
commands.

Due to a subtle oversight, this means that since we did
that, executor_test's `chkSumCluster` has been dutifully
printing `hash:blahblahblah` to os.Stdout, and returning
an empty string.

This also, indirectly, fixes a very strange behavior
we've had ever since then, which is that a lot of test
output silently disappears. The reason is probably,
although I haven't found the right code path, that we
were ending up closing os.Stdout.

cmd/chksum.go

@@ -3,13 +3,15 @@
 package cmd
 
 import (
+	"os"
+
 	"github.com/featurebasedb/featurebase/v3/ctl"
 	"github.com/featurebasedb/featurebase/v3/logger"
 	"github.com/spf13/cobra"
 )
 
 func newChkSumCommand(logdest logger.Logger) *cobra.Command {
-	cmd := ctl.NewChkSumCommand(logdest)
+	cmd := ctl.NewChkSumCommand(logdest, os.Stdout)
 	ccmd := &cobra.Command{
 		Use:   "chksum",
 		Short: "Digital signature of FeatureBase data",

ctl/chksum.go

@@ -7,7 +7,6 @@ import (
 	"crypto/tls"
 	"fmt"
 	"io"
-	"os"
 
 	"github.com/cespare/xxhash"
 	pilosa "github.com/featurebasedb/featurebase/v3"
@@ -38,9 +37,9 @@ func (cmd *ChkSumCommand) Logger() logger.Logger {
 }
 
 // NewChkSumCommand returns a new instance of BackupCommand.
-func NewChkSumCommand(logdest logger.Logger) *ChkSumCommand {
+func NewChkSumCommand(logdest logger.Logger, stdout io.Writer) *ChkSumCommand {
 	return &ChkSumCommand{
-		stdout:  os.Stdout,
+		stdout:  stdout,
 		logDest: logdest,
 	}
 }

ctl/chksum_test.go

@@ -13,9 +13,8 @@ import (
 
 func TestChkSumCommand_Run(t *testing.T) {
 	cmLog := logger.NewStandardLogger(os.Stderr)
-	cm := NewChkSumCommand(cmLog)
 	buf := &bytes.Buffer{}
-	cm.stdout = buf
+	cm := NewChkSumCommand(cmLog, buf)
 
 	cluster := test.MustRunCluster(t, 1)
 	defer cluster.Close()

executor_test.go

@@ -7447,15 +7447,16 @@ func backupTarTest(t *testing.T, c *test.Cluster, index string) {
 
 func chkSumCluster(t *testing.T, c *test.Cluster) string {
 	t.Helper()
-	buf := &bytes.Buffer{}
-	chkSumLog := logger.NewStandardLogger(buf)
-	chkSum := ctl.NewChkSumCommand(chkSumLog)
+	errBuf := &bytes.Buffer{}
+	outBuf := &bytes.Buffer{}
+	chkSumLog := logger.NewStandardLogger(errBuf)
+	chkSum := ctl.NewChkSumCommand(chkSumLog, outBuf)
 	chkSum.Host = c.Nodes[len(c.Nodes)-1].URL()
 	if err := chkSum.Run(context.Background()); err != nil {
 		t.Fatalf("running checksum: %v", err)
 	}
 
-	return buf.String()
+	return outBuf.String()
 }
 
 func backupCluster(t *testing.T, c *test.Cluster, index string) (backupDir string) {