setUp/tearDown may be called repeatedly in a group.

lib/test.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library test;
 
 import 'dart:async';
 
 import 'package:path/path.dart' as p;
 
@@ skipping 151 matching lines @@
         testOn: testOn, timeout: timeout, skip: skip);
 
 /// Registers a function to be run before tests.
 ///
 /// This function will be called before each test is run. [callback] may be
 /// asynchronous; if so, it must return a [Future].
 ///
 /// If this is called within a test group, it applies only to tests in that
 /// group. [callback] will be run after any set-up callbacks in parent groups or
 /// at the top level.
+///
+/// Each callback at the top level or in a given group will be run in the order
+/// they were declared.
 void setUp(callback()) => _declarer.setUp(callback);
 
 /// Registers a function to be run after tests.
 ///
 /// This function will be called after each test is run. [callback] may be
 /// asynchronous; if so, it must return a [Future].
 ///
 /// If this is called within a test group, it applies only to tests in that
 /// group. [callback] will be run before any tear-down callbacks in parent
 /// groups or at the top level.
+///
+/// Each callback at the top level or in a given group will be run in the
+/// reverse of the order they were declared.
 void tearDown(callback()) => _declarer.tearDown(callback);
 
 /// Registers an exception that was caught for the current test.
 void registerException(error, [StackTrace stackTrace]) {
   // This will usually forward directly to [Invoker.current.handleError], but
   // going through the zone API allows other zones to consistently see errors.
   Zone.current.handleUncaughtError(error, stackTrace);
 }