code: public <K, V> void assertContainsOnly(Description description, Map<K, V> actual, MapEntry[] entries) {
      isNotEmptyOrNull(entries);
      assertNotNull(description, actual);
      Map<K, V> notExpected = new LinkedHashMap<K, V>(actual);
      Set<MapEntry> notFound = containsOnly(actual, entries, notExpected);
      if (!notFound.isEmpty() || !notExpected.isEmpty()) {
        throw failures.failure(description, shouldContainOnly(actual, entries, notFound, notExpected));
      }
    }
docs: Asserts that the given {@code Map} contains only the given entries, nothing else.
  
  @param description contains information about the assertion.
  @param actual the given {@code Map}.
  @param entries the entries that are expected to be in the given {@code Map}.
  @throws NullPointerException if the array of entries is {@code null}.
  @throws IllegalArgumentException if the array of entries is empty.
  @throws NullPointerException if any of the entries in the given array is {@code null}.
  @throws AssertionError if the given {@code Map} is {@code null}.
  @throws AssertionError if the given {@code Map} does not contain the given entries.