test/py: check return code of helloworld

Check that helloworld.efi returns EFI_SUCCESS.

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Alexander Graf <agraf@suse.de>
diff --git a/test/py/tests/test_efi_loader.py b/test/py/tests/test_efi_loader.py
index 4d391e1..906ef2f 100644
--- a/test/py/tests/test_efi_loader.py
+++ b/test/py/tests/test_efi_loader.py
@@ -154,6 +154,8 @@
     output = u_boot_console.run_command('bootefi %x' % addr)
     expected_text = 'Hello, world'
     assert expected_text in output
+    expected_text = '## Application terminated, r = 0'
+    assert expected_text in output
 
 @pytest.mark.buildconfigspec('cmd_bootefi_hello')
 def test_efi_helloworld_builtin(u_boot_console):