Pass SHELL environment variable to subshell

diff --git a/cmd/asdf/main_test.go b/cmd/asdf/main_test.go
index 38c39c7..83d5c86 100644
--- a/cmd/asdf/main_test.go
+++ b/cmd/asdf/main_test.go
@@ -2,6 +2,7 @@ package main
 
 import (
 	"fmt"
+	"os"
 	"os/exec"
 	"strings"
 	"testing"
@@ -126,7 +127,8 @@ func runBatsFile(t *testing.T, dir, filename string) {
 	// Add dir to asdf test variables
 	asdfTestHome := fmt.Sprintf("BASE_DIR=%s", dir)
 	asdfBinPath := fmt.Sprintf("ASDF_BIN=%s", dir)
-	cmd.Env = []string{asdfBinPath, asdfTestHome}
+	shellEnv := fmt.Sprintf("SHELL=%s", os.Getenv("SHELL"))
+	cmd.Env = []string{asdfBinPath, asdfTestHome, shellEnv}
 
 	err := cmd.Run()
 	if err != nil {