### Question:
FlatVariableScope implements VariableScope { public Optional<Variable> lookup(String identifier) { return Optional.ofNullable(variables.get(identifier)); }  Variable declare(String scopeId, String identifier, String type); Variable declare(String scopeId, String identifier, String type, String tags); Optional<Variable> lookup(String identifier); Collection<Variable> getVariables(String scopeId);  }### Answer:
@Test public void lookupNotFound() { Optional<VariableScope.Variable> variable = tested.lookup(UUID.randomUUID().toString()); assertFalse(variable.isPresent()); }