}
@Test
public void override_env_variables() {
System2 system = mock(System2.class);
when(system.envVariables()).thenReturn(ImmutableMap.of("JAVA_HOME", "/default/path/to/java"));
Command command = new Command("java", system);
command.setEnvironmentVariable("JAVA_HOME", "/new/path/to/java");
assertThat(command.getEnvironmentVariables().get("JAVA_HOME")).isEqualTo("/new/path/to/java");
}