diff --git a/errors_test.go b/errors_test.go
index fdebb52..247a4d2 100644
--- a/errors_test.go
+++ b/errors_test.go
@@ -11,6 +11,7 @@ import (
 func TestErrors(t *testing.T) {
 	var errors runn.Errors
 	errors.Add(fmt.Errorf("error1"))
+	errors.Add(nil)
 	errors.Add(fmt.Errorf("error2"))
 	errors.Add(fmt.Errorf("error3"))
 
diff --git a/executor.go b/executor.go
index c6f767b..c289a9e 100644
--- a/executor.go
+++ b/executor.go
@@ -1,11 +1,5 @@
 package runn
 
-import (
-	"bytes"
-	"fmt"
-	"os/exec"
-)
-
 // Executor do the code statement execution
 type Executor struct {
 	StopWhenError bool
@@ -31,20 +25,6 @@ func (e Executor) Execute(stmts ...interface{}) (err error) {
 				}
 				errs.Add(runErr)
 			}
-		case *exec.Cmd:
-			execCmd := stmt.(*exec.Cmd)
-			buf := bytes.Buffer{}
-			execCmd.Stdout = &buf
-			execCmd.Stderr = &buf
-
-			runErr := execCmd.Run()
-			if err != nil {
-				runErr = fmt.Errorf("%s: %s", err.Error(), buf.String())
-				if e.StopWhenError {
-					return runErr
-				}
-				errs.Add(runErr)
-			}
 		}
 	}
 	if len(errs) > 0 {
diff --git a/executor_test.go b/executor_test.go
index dcdb57f..fc0bbc1 100644
--- a/executor_test.go
+++ b/executor_test.go
@@ -12,7 +12,7 @@ import (
 
 type RunnerImplementationWithError struct{}
 
-func (i RunnerImplementationWithError) Run() error { return errors.New("some-error") }
+func (i RunnerImplementationWithError) Run() error { return errors.New("some-runner-error") }
 
 type RunnerImplementationNoError struct{}
 
@@ -27,12 +27,12 @@ func TestExecutor_All(t *testing.T) {
 		{
 			false,
 			[]interface{}{
-				RunnerImplementationWithError{},
 				errors.New("error1"),
+				RunnerImplementationWithError{},
 				errors.New("error2"),
 				exec.Command("wrong-command", "bad-argument"),
 			},
-			errors.New("some-error; error1; error2; exec: \"wrong-command\": executable file not found in $PATH"),
+			errors.New("error1; some-runner-error; error2; exec: \"wrong-command\": executable file not found in $PATH"),
 		},
 		{
 			true,
@@ -43,15 +43,27 @@ func TestExecutor_All(t *testing.T) {
 			errors.New("error1"),
 		},
 		{
-			false,
-			[]interface{}{},
-			nil,
+			true,
+			[]interface{}{
+				RunnerImplementationWithError{},
+				errors.New("unreachable-error"),
+			},
+			errors.New("some-runner-error"),
 		},
 		{
 			true,
+			[]interface{}{
+				exec.Command("wrong-command", "bad-argument"),
+				errors.New("unreachable-error"),
+			},
+			errors.New("exec: \"wrong-command\": executable file not found in $PATH"),
+		},
+		{
+			false,
 			[]interface{}{},
 			nil,
 		},
+
 		{
 			false,
 			[]interface{}{
diff --git a/runner.go b/runner.go
index f13854a..2a24e9c 100644
--- a/runner.go
+++ b/runner.go
@@ -1,5 +1,6 @@
 package runn
 
+// Runner contain run function
 type Runner interface {
 	Run() error
 }