added tests for eval command runner

zs.go

@@ -110,10 +110,13 @@ func eval(cmd []string, vars map[string]string) (string, error) {
 	outbuf := bytes.NewBuffer(nil)
 	err := run(path.Join(ZSDIR, cmd[0]), cmd[1:], vars, outbuf)
 	if err != nil {
-		log.Println(err)
+		if _, ok := err.(*exec.ExitError); ok {
+			return "", err
+		}
 		outbuf = bytes.NewBuffer(nil)
 		err := run(cmd[0], cmd[1:], vars, outbuf)
-		if err != nil {
+		// Return exit errors, but ignore if the command was not found
+		if _, ok := err.(*exec.ExitError); ok {
 			return "", err
 		}
 	}

zs_test.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"log"
 	"os"
+	"os/exec"
 	"strings"
 	"testing"
 )
@@ -123,6 +124,24 @@ func TestRun(t *testing.T) {
 	}
 }
 
+func TestEvalCommand(t *testing.T) {
+	s, err := eval([]string{"echo", "hello"}, map[string]string{})
+	if err != nil {
+		t.Error(err)
+	}
+	if s != "hello\n" {
+		t.Error(s)
+	}
+	_, err = eval([]string{"cat", "bogus/file"}, map[string]string{})
+	if _, ok := err.(*exec.ExitError); !ok {
+		t.Error("expected ExitError")
+	}
+	_, err = eval([]string{"missing command"}, map[string]string{})
+	if err != nil {
+		t.Error("missing command should be ignored")
+	}
+}
+
 func TestHelperProcess(*testing.T) {
 	if os.Getenv("ZS_HELPER") != "1" {
 		return