diff --git a/bin/asdf b/bin/asdf
index c5ad13d0..e064320e 100755
--- a/bin/asdf
+++ b/bin/asdf
@@ -44,71 +44,72 @@ source "$(dirname "$(dirname "$0")")/lib/commands/plugin-test.sh"
 # shellcheck disable=SC2124
 callback_args="${@:2}"
 
+# shellcheck disable=SC2086
 case $1 in
 
 "--version")
-    asdf_version "$callback_args";;
+    asdf_version $callback_args;;
 
 "help")
-    help_command "$callback_args";;
+    help_command $callback_args;;
 
 "update")
-    update_command "$callback_args";;
+    update_command $callback_args;;
 
 "install")
-    install_command "$callback_args";;
+    install_command $callback_args;;
 
 "uninstall")
-    uninstall_command "$callback_args";;
+    uninstall_command $callback_args;;
 
 "current")
-    current_command "$callback_args";;
+    current_command $callback_args;;
 
 "where")
-    where_command "$callback_args";;
+    where_command $callback_args;;
 
 "which")
-    which_command "$callback_args";;
+    which_command $callback_args;;
 
 "local")
-    local_command "$callback_args";;
+    local_command $callback_args;;
 
 "global")
-    global_command "$callback_args";;
+    global_command $callback_args;;
 
 "list")
-    list_command "$callback_args";;
+    list_command $callback_args;;
 
 "list-all")
-    list_all_command "$callback_args";;
+    list_all_command $callback_args;;
 
 "shim")
-    shim_command "$callback_args";;
+    shim_command $callback_args;;
 
 "reshim")
-    reshim_command "$callback_args";;
+    reshim_command $callback_args;;
 
 "plugin-add")
-    plugin_add_command "$callback_args";;
+    plugin_add_command $callback_args;;
 
 "plugin-list")
-    plugin_list_command "$callback_args";;
+    plugin_list_command $callback_args;;
 
 "plugin-list-all")
-    plugin_list_all_command "$callback_args";;
+    plugin_list_all_command $callback_args;;
 
 "plugin-update")
-    plugin_update_command "$callback_args";;
+    plugin_update_command $callback_args;;
 
 "plugin-remove")
-    plugin_remove_command "$callback_args";;
+    plugin_remove_command $callback_args;;
 
 # Undocumented commands for development
 "plugin-push")
-    plugin_push_command "$callback_args";;
+    plugin_push_command $callback_args;;
 
 "plugin-test")
-    plugin_test_command "$callback_args";;
+    plugin_test_command $callback_args;;
 
 *)
   help_command
diff --git a/lib/commands/plugin-test.sh b/lib/commands/plugin-test.sh
index c577895a..142821a2 100644
--- a/lib/commands/plugin-test.sh
+++ b/lib/commands/plugin-test.sh
@@ -7,8 +7,8 @@ fail_test() {
 }
 
 plugin_test_command() {
-    export ASDF_DIR
     ASDF_DIR=$(mktemp -dt asdf.XXXX)
+    export ASDF_DIR
     git clone https://github.com/asdf-vm/asdf.git "$ASDF_DIR"
 
     local plugin_name=$1
@@ -19,11 +19,11 @@ plugin_test_command() {
         fail_test "please provide a plugin name and url"
     fi
 
-    if ! asdf plugin-add "$plugin_name" "$plugin_url"; then
+    if ! (asdf plugin-add "$plugin_name" "$plugin_url"); then
         fail_test "could not install $plugin_name from $plugin_url"
     fi
 
-    if ! asdf plugin-list | grep "$plugin_name" > /dev/null; then
+    if ! (asdf plugin-list | grep "$plugin_name" > /dev/null); then
         fail_test "$plugin_name was not properly installed"
     fi
 
@@ -40,24 +40,25 @@ plugin_test_command() {
     local latest_version
     latest_version=${versions[${#versions[@]} - 1]}
 
-    if ! asdf install "$plugin_name" "$latest_version"; then
+    if ! (asdf install "$plugin_name" "$latest_version"); then
         fail_test "install exited with an error"
     fi
 
     cd "$ASDF_DIR" || fail_test "could not cd $ASDF_DIR"
 
-    if ! asdf local "$plugin_name" "$latest_version"; then
+    if ! (asdf local "$plugin_name" "$latest_version"); then
         fail_test "install did not add the requested version"
     fi
 
-    if ! asdf reshim "$plugin_name"; then
+    if ! (asdf reshim "$plugin_name"); then
         fail_test "could not reshim plugin"
     fi
 
     if [ -n "$plugin_command" ]; then
-        (env PATH="$ASDF_DIR/bin:$ASDF_DIR/shims:$PATH" eval "$plugin_command")
+        (PATH="$ASDF_DIR/bin:$ASDF_DIR/shims:$PATH" eval "$plugin_command")
+        local exit_code
         exit_code=$?
-        if [ $exit_code -ne 0 ]; then
+        if [ $exit_code != 0 ]; then
             fail_test "$plugin_command failed with exit code $?"
         fi
     fi