@Override
  public void verifyInteractions() {
    List<IMockInteraction> unsatisfiedInteractions = new ArrayList<>();

    for (IMockInteraction interaction : interactions)
      if (!interaction.isSatisfied()) unsatisfiedInteractions.add(interaction);

    if (!unsatisfiedInteractions.isEmpty())
      throw new TooFewInvocationsError(unsatisfiedInteractions, unmatchedInvocations);
  }
A scope for interactions defined outside a then-block

@author Peter Niederwieser
spock-core/src/main/java/org/spockframework/mock/runtime/InteractionScope.java