src/main/java/org/fest/assertions/internal/Sets.java
public void assertNullOrEmpty(Description description, Set<?> actual) {
    if (actual == null || actual.isEmpty()) {
      return;
    }
    throw failures.failure(description, shouldBeNullOrEmpty(actual));
  }
public void assertNullOrEmpty(Description description, Set<?> actual) {
    if (actual == null || actual.isEmpty()) {
      return;
    }
    throw failures.failure(description, shouldBeNullOrEmpty(actual));
  }
Asserts that the given <code>{@link Set}</code> is {@code null} or empty.

@param description contains information about the assertion.
@param actual the given {@code Set}.
@throws AssertionError if the given {@code Set} is not {@code null} *and* contains one or more elements.