Fix coverage tests

2 problems:
  - spawnCmdWithLogger was not implemented (when built with 'cov' tag)
  - the logic was depending on relative paths. We change it to absolute
to be able to run in the test-specific temporary directories.

tests/e2e/etcd_spawn_cov.go

@@ -19,31 +19,41 @@ package e2e
 
 import (
 	"fmt"
-	"log"
 	"os"
 	"path/filepath"
+	"strings"
 	"syscall"
 	"time"
 
 	"go.etcd.io/etcd/client/pkg/v3/fileutil"
 	"go.etcd.io/etcd/pkg/v3/expect"
+	"go.uber.org/zap"
 )
 
 const noOutputLineCount = 2 // cov-enabled binaries emit PASS and coverage count lines
 
 func spawnCmd(args []string) (*expect.ExpectProcess, error) {
+	return spawnCmdWithLogger(zap.NewNop(), args)
+}
+
+func spawnCmdWithLogger(lg *zap.Logger, args []string) (*expect.ExpectProcess, error) {
 	cmd := args[0]
 	env := make([]string, 0)
-	switch cmd {
-	case binPath:
-		cmd = "../../bin/etcd_test"
-	case ctlBinPath:
-		cmd = "../../bin/etcdctl_test"
-	case ctlBinPath + "3":
-		cmd = "../../bin/etcdctl_test"
+	switch {
+	case strings.HasSuffix(cmd, "/etcd"):
+		cmd = cmd + "_test"
+	case strings.HasSuffix(cmd, "/etcdctl"):
+		cmd = cmd + "_test"
+	case strings.HasSuffix(cmd, "/etcdctl3"):
+		cmd = ctlBinPath + "_test"
 		env = append(env, "ETCDCTL_API=3")
 	}
 
+	wd, err := os.Getwd()
+	if err != nil {
+		return nil, err
+	}
+
 	covArgs, err := getCovArgs()
 	if err != nil {
 		return nil, err
@@ -52,7 +62,7 @@ func spawnCmd(args []string) (*expect.ExpectProcess, error) {
 	// they must be included in ctl_cov_env.
 	env = append(env, os.Environ()...)
 	all_args := append(args[1:], covArgs...)
-	log.Printf("Executing %v %v", cmd, all_args)
+	lg.Info("spawning process", zap.Strings("args", all_args), zap.String("working-dir", wd))
 	ep, err := expect.NewExpectWithEnv(cmd, all_args, env)
 	if err != nil {
 		return nil, err