def METHOD_NAME(self):
    self.provision_config_instance.variables["system"]["env"]["passenv"] = "JAVA_HOME,FOO1"
    os.environ["JAVA_HOME"] = "/path/to/java"
    os.environ["FOO1"] = "BAR1"
    telem = telemetry.Telemetry()
    # no JAVA_HOME -> use the bundled JDK
    env = self.launcher._prepare_env(node_name="node0", java_home=None, telemetry=telem)
    # unmodified
    self.assertEqual(os.environ["JAVA_HOME"], env["JAVA_HOME"])
    self.assertEqual(os.environ["FOO1"], env["FOO1"])
    self.assertEqual(env["OPENSEARCH_JAVA_OPTS"], "-XX:+ExitOnOutOfMemoryError")