Clean up unittest a bunch.

lib/unittest.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.
 
 /// Support for writing Dart unit tests.
 ///
 /// For information on installing and importing this library, see the
 /// [unittest package on pub.dartlang.org]
 /// (http://pub.dartlang.org/packages/unittest).
 ///
@@ skipping 118 matching lines @@
 ///           var delta = new DateTime.now().difference(time);
 ///
 ///           expect(delta, greaterThanOrEqualTo(duration));
 ///         });
 ///       });
 ///     }
 library unittest;
 
 import 'dart:async';
 import 'dart:collection';
-import 'dart:isolate';
-
-import 'package:matcher/matcher.dart' show DefaultFailureHandler,
-    configureExpectFailureHandler, TestFailure, wrapAsync;
+
+import 'package:matcher/matcher.dart' show TestFailure, wrapAsync;
+
+import 'src/configuration.dart';
+import 'src/expected_function.dart';
+import 'src/group_context.dart';
+import 'src/internal_test_case.dart';
+import 'src/test_case.dart';
+import 'src/test_environment.dart';
+
 export 'package:matcher/matcher.dart';
 
-import 'src/utils.dart';
-
-import 'src/configuration.dart';
 export 'src/configuration.dart';
-
-part 'src/simple_configuration.dart';
-part 'src/group_context.dart';
-part 'src/spread_args_helper.dart';
-part 'src/test_case.dart';
-part 'src/test_environment.dart';
-
-const Symbol _UNITTEST_ENVIRONMENT = #unittest.environment;
-
-final _TestEnvironment _defaultEnvironment = new _TestEnvironment();
-
-/**
- * Internal getter for the current unittest config.
- */
-_TestEnvironment get _environment {
-  var environment = Zone.current[_UNITTEST_ENVIRONMENT];
-  if (environment == null) return _defaultEnvironment;
-  return environment;
-}
-
-// Convenience getter for the current environment's config.
-Configuration get _config => _environment.config;
-
-// Convenience setter for the current environment's config.
-void set _config(Configuration config) {
-  _environment.config = config;
-}
-
-// Convenience getter for the current environment's test cases.
-List<TestCase> get _testCases => _environment.testCases;
+export 'src/simple_configuration.dart';
+export 'src/test_case.dart';
+
+/// The signature for a function passed to [test].
+typedef dynamic TestFunction();
 
 /// [Configuration] used by the unittest library.
 ///
 /// Note that if a configuration has not been set, calling this getter will
 /// create a default configuration.
 Configuration get unittestConfiguration {
-  if (_config == null) {
-    _config = new Configuration();
-  }
-  return _config;
-}
+  if (config == null) environment.config = new Configuration();
+  return config;
+}
+
+/// If `true`, stack traces are reformatted to be more readable.
+bool formatStacks = true;
+
+/// If `true`, irrelevant frames are filtered from the stack trace.
+///
+/// This does nothing if [formatStacks] is false.
+bool filterStacks = true;
+
+/// Separator used between group names and test names.
+String groupSep = ' ';
 
 /// Sets the [Configuration] used by the unittest library.
 ///
 /// Throws a [StateError] if there is an existing, incompatible value.
 void set unittestConfiguration(Configuration value) {
-  if (!identical(_config, value)) {
-    if (_config != null) {
-      logMessage('Warning: The unittestConfiguration has already been set. New '
-          'unittestConfiguration ignored.');
-    } else {
-      _config = value;
-    }
-  }
-}
-
-/// Can be called by tests to log status. Tests should use this
-/// instead of [print].
+  if (identical(config, value)) return;
+  if (config != null) {
+    logMessage('Warning: The unittestConfiguration has already been set. New '
+        'unittestConfiguration ignored.');
+  } else {
+    environment.config = value;
+  }
+}
+
+/// Logs [message] associated with the current test case.
+///
+/// Tests should use this instead of [print].
 void logMessage(String message) =>
-    _config.onLogMessage(currentTestCase, message);
-
-/// Separator used between group names and test names.
-String groupSep = ' ';
-
-/// Tests executed in this suite.
+    config.onLogMessage(currentTestCase, message);
+
+/// The test cases that have been defined so far.
 List<TestCase> get testCases =>
-    new UnmodifiableListView<TestCase>(_environment.testCases);
-
-/// Interval (in msecs) after which synchronous tests will insert an async
-/// delay to allow DOM or other updates.
+    new UnmodifiableListView<TestCase>(environment.testCases);
+
+/// The interval (in milliseconds) after which a non-microtask asynchronous
+/// delay will be scheduled between tests.
+///
+/// This is used to avoid starving the DOM or other non-microtask events.
 const int BREATH_INTERVAL = 200;
 
-/// [TestCase] currently being executed.
+/// The [TestCase] currently being executed.
 TestCase get currentTestCase =>
-    (_environment.currentTestCaseIndex >= 0 &&
-     _environment.currentTestCaseIndex < testCases.length)
-        ? testCases[_environment.currentTestCaseIndex]
+    (environment.currentTestCaseIndex >= 0 &&
+     environment.currentTestCaseIndex < testCases.length)
+        ? testCases[environment.currentTestCaseIndex]
         : null;
 
-/* Test case result strings. */
-// TODO(gram) we should change these constants to use a different string
-// (so that writing 'FAIL' in the middle of a test doesn't
-// imply that the test fails). We can't do it without also changing
-// the testrunner and test.dart though.
-/// Result string for a passing test case.
+/// The same as [currentTestCase], but typed as an [InternalTestCase].
+InternalTestCase get _currentTestCase => currentTestCase as InternalTestCase;
+
+/// The result string for a passing test case.
 const PASS = 'pass';
-/// Result string for a failing test case.
+
+/// The result string for a failing test case.
 const FAIL = 'fail';
-/// Result string for an test case with an error.
+
+/// The result string for an test case with an error.
 const ERROR = 'error';
 
-/// Creates a new test case with the given description and body. The
-/// description will include the descriptions of any surrounding group()
-/// calls.
-void test(String spec, TestFunction body) {
+/// Creates a new test case with the given description and body.
+///
+/// The description will be added to the descriptions of any surrounding
+/// [group]s.
+void test(String description, TestFunction body) {
   _requireNotRunning();
   ensureInitialized();
-  if (!_environment.soloTestSeen || _environment.soloNestingLevel > 0) {
-    var testcase = new TestCase._internal(testCases.length + 1, _fullSpec(spec),
-        body);
-    _testCases.add(testcase);
-  }
-}
-
-/// Convenience function for skipping a test.
+
+  if (environment.soloTestSeen && environment.soloNestingLevel == 0) return;
+  var testCase = new InternalTestCase(
+      testCases.length + 1, _fullDescription(description), body);
+  environment.testCases.add(testCase);
+}
+
+/// Returns [description] with all of its group prefixes prepended.
+String _fullDescription(String description) {
+  var group = environment.currentContext.fullName;
+  if (description == null) return group;
+  return group != '' ? '$group$groupSep$description' : description;
+}
+
+/// A convenience function for skipping a test.
 void skip_test(String spec, TestFunction body) {}
 
-/// Creates a new test case with the given description and body. The
-/// description will include the descriptions of any surrounding group()
-/// calls.
-///
-/// If we use [solo_test] (or [solo_group]) instead of test, then all non-solo
-/// tests will be disabled. Note that if we use [solo_group], all tests in
-/// the group will be enabled, regardless of whether they use [test] or
-/// [solo_test], or whether they are in a nested [group] vs [solo_group]. Put
-/// another way, if there are any calls to [solo_test] or [solo_group] in a test
-/// file, all tests that are not inside a [solo_group] will be disabled unless
-/// they are [solo_test]s.
-///
-/// [skip_test] and [skip_group] take precedence over soloing, by virtue of the
-/// fact that they are effectively no-ops.
+/// Creates a new test case with the given description and body.
+///
+/// If [solo_test] is used instead of [test], then all non-solo tests will be
+/// disabled. Note that if [solo_group] is used as well, all tests in the group
+/// will be enabled, regardless of whether they use [test] or [solo_test], or
+/// whether they are in a nested [group] versus [solo_group]. Put another way,
+/// if there are any calls to [solo_test] or [solo_group] in a test file, all
+/// tests that are not inside a [solo_group] will be disabled unless they are
+/// [solo_test]s.
 void solo_test(String spec, TestFunction body) {
   _requireNotRunning();
   ensureInitialized();
-  if (!_environment.soloTestSeen) {
-    _environment.soloTestSeen = true;
+  if (!environment.soloTestSeen) {
+    environment.soloTestSeen = true;
     // This is the first solo-ed test. Discard all tests up to now.
-    _testCases.clear();
-  }
-  ++_environment.soloNestingLevel;
+    environment.testCases.clear();
+  }
+  environment.soloNestingLevel++;
   try {
     test(spec, body);
   } finally {
-    --_environment.soloNestingLevel;
-  }
-}
-
-/// Indicate that [callback] is expected to be called a [count] number of times
+    environment.soloNestingLevel--;
+  }
+}
+
+/// Indicate that [callback] is expected to be called [count] number of times
 /// (by default 1).
 ///
-/// The unittest framework will wait for the callback to run the
-/// specified [count] times before it continues with the following test.  Using
-/// [expectAsync] will also ensure that errors that occur within [callback] are
-/// tracked and reported. [callback] should take 0 positional arguments (named
-/// arguments are not supported). [id] can be used to provide more
-/// descriptive error messages if the callback is called more often than
-/// expected.
-///
-/// [max] can be used to specify an upper bound on the number of
-/// calls; if this is exceeded the test will fail (or be marked as in error if
-/// it was already complete). A value of 0 for [max] (the default) will set
-/// the upper bound to the same value as [count]; i.e. the callback should be
-/// called exactly [count] times. A value of -1 for [max] will mean no upper
-/// bound.
-///
-/// [reason] is optional and is typically not supplied, as a reason is generated
-/// by the unittest package; if reason is included it is appended to the
-/// generated reason.
+/// The unittest framework will wait for the callback to run the [count] times
+/// before it considers the current test to be complete. Using [expectAsync]
+/// will also ensure that errors that occur within [callback] are tracked and
+/// reported. [callback] may take up to six optional or required positional
+/// arguments; named arguments are not supported.
+///
+/// [max] can be used to specify an upper bound on the number of calls; if this
+/// is exceeded the test will fail. If [max] is `0` (the default), the callback
+/// is expected to be called exactly [count] times. If [max] is `-1`, the
+/// callback is allowed to be called any number of times greater than [count].
+///
+/// Both [id] and [reason] are optional and provide extra information about the
+/// callback when debugging. [id] should be the name of the callback, while
+/// [reason] should be the reason the callback is expected to be called.
 Function expectAsync(Function callback,
     {int count: 1, int max: 0, String id, String reason}) =>
-  new _SpreadArgsHelper(callback, count, max, id, reason).func;
+  new ExpectedFunction(callback, count, max, id: id, reason: reason).func;
 
 /// Indicate that [callback] is expected to be called until [isDone] returns
 /// true.
 ///
-/// The unittest framework checks [isDone] after each callback and only
-/// when it returns true will it continue with the following test. Using
-/// [expectAsyncUntil] will also ensure that errors that occur within
-/// [callback] are tracked and reported. [callback] should take 0 positional
-/// arguments (named arguments are not supported). [id] can be used to
-/// identify the callback in error messages (for example if it is called
-/// after the test case is complete).
-///
-/// [reason] is optional and is typically not supplied, as a reason is generated
-/// by the unittest package; if reason is included it is appended to the
-/// generated reason.
-Function expectAsyncUntil(Function callback, bool isDone(),
-    {String id, String reason}) =>
-  new _SpreadArgsHelper(callback, 0, -1, id, reason, isDone: isDone).func;
-
-/// Creates a new named group of tests.
-///
-/// Calls to group() or test() within the body of the function passed to this
-/// named group will inherit this group's description.
+/// [isDone] is called after each time the function is run. Only when it returns
+/// true will the callback be considered complete. Using [expectAsyncUntil] will
+/// also ensure that errors that occur within [callback] are tracked and
+/// reported. [callback] may take up to six optional or required positional
+/// arguments; named arguments are not supported.
+///
+/// Both [id] and [reason] are optional and provide extra information about the
+/// callback when debugging. [id] should be the name of the callback, while
+/// [reason] should be the reason the callback is expected to be called.
+Function expectAsyncUntil(Function callback, bool isDone(), {String id,
+    String reason}) =>
+  new ExpectedFunction(callback, 0, -1, id: id, reason: reason, isDone: isDone)
+      .func;
+
+/// Creates a group of tests.
+///
+/// A group's description is included in the descriptions of any tests or
+/// sub-groups it contains. [setUp] and [tearDown] are also scoped to the
+/// containing group.
 void group(String description, void body()) {
   ensureInitialized();
   _requireNotRunning();
-  _environment.currentContext =
-      new _GroupContext(_environment.currentContext, description);
+  environment.currentContext =
+      new GroupContext(environment.currentContext, description);
   try {
     body();
   } catch (e, trace) {
     var stack = (trace == null) ? '' : ': ${trace.toString()}';
-    _environment.uncaughtErrorMessage = "${e.toString()}$stack";
+    environment.uncaughtErrorMessage = "${e.toString()}$stack";
   } finally {
     // Now that the group is over, restore the previous one.
-    _environment.currentContext = _environment.currentContext.parent;
-  }
-}
-
-/// Like [skip_test], but for groups.
+    environment.currentContext = environment.currentContext.parent;
+  }
+}
+
+/// A convenience function for skipping a group of tests.
 void skip_group(String description, void body()) {}
 
-/// Like [solo_test], but for groups.
+/// Creates a group of tests.
+///
+/// If [solo_group] is used instead of [group], then all tests not declared with
+/// [solo_test] or in a [solo_group] will be disabled. Note that all tests in a
+/// [solo_group] will be run, regardless of whether they're declared with [test]
+/// or [solo_test].
+///
+/// [skip_test] and [skip_group] take precedence over [solo_group].
 void solo_group(String description, void body()) {
   _requireNotRunning();
   ensureInitialized();
-  if (!_environment.soloTestSeen) {
-    _environment.soloTestSeen = true;
+  if (!environment.soloTestSeen) {
+    environment.soloTestSeen = true;
     // This is the first solo-ed group. Discard all tests up to now.
-    _testCases.clear();
-  }
-  ++_environment.soloNestingLevel;
+    environment.testCases.clear();
+  }
+  ++environment.soloNestingLevel;
   try {
     group(description, body);
   } finally {
-    --_environment.soloNestingLevel;
-  }
-}
-
-/// Register a [setUp] function for a test [group].
-///
-/// This function will be called before each test in the group is run.
-/// [setUp] and [tearDown] should be called within the [group] before any
-/// calls to [test]. The [setupTest] function can be asynchronous; in this
-/// case it must return a [Future].
-void setUp(Function setupTest) {
-  _requireNotRunning();
-  _environment.currentContext.testSetup = setupTest;
-}
-
-/// Register a [tearDown] function for a test [group].
-///
-/// This function will be called after each test in the group is run.
-///
-/// Note that if groups are nested only the most locally scoped [teardownTest]
-/// function will be run. [setUp] and [tearDown] should be called within the
-/// [group] before any calls to [test]. The [teardownTest] function can be
-/// asynchronous; in this case it must return a [Future].
-void tearDown(Function teardownTest) {
-  _requireNotRunning();
-  _environment.currentContext.testTeardown = teardownTest;
+    --environment.soloNestingLevel;
+  }
+}
+
+/// 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.
+void setUp(Function callback) {
+  _requireNotRunning();
+  environment.currentContext.testSetUp = 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.
+void tearDown(Function callback) {
+  _requireNotRunning();
+  environment.currentContext.testTearDown = callback;
 }
 
 /// Advance to the next test case.
 void _nextTestCase() {
-  _environment.currentTestCaseIndex++;
+  environment.currentTestCaseIndex++;
   _runTest();
 }
 
-/// Handle errors that happen outside the tests.
-// TODO(vsm): figure out how to expose the stack trace here
-// Currently e.message works in dartium, but not in dartc.
-void handleExternalError(e, String message, [stack]) {
+/// Handle an error that occurs outside of any test.
+void handleExternalError(e, String message, [stackTrace]) {
   var msg = '$message\nCaught $e';
 
   if (currentTestCase != null) {
-    currentTestCase._error(msg, stack);
+    _currentTestCase.error(msg, stackTrace);
   } else {
-    _environment.uncaughtErrorMessage = "$msg: $stack";
-  }
-}
-
-/// Filter the tests by [testFilter].
-///
-/// [testFilter] can be a [RegExp], a [String] or a
-/// predicate function. This is different from enabling or disabling tests
-/// in that it removes the tests completely.
+    environment.uncaughtErrorMessage = "$msg: $stackTrace";
+  }
+}
+
+/// Remove any tests that match [testFilter].
+///
+/// [testFilter] can be a predicate function, a [RegExp], or a [String]. If it's
+/// a function, it's called with each [TestCase]. If it's a [String], it's
+/// parsed as a [RegExp] and matched against each [TestCase.description].
+///
+/// This is different from enabling or disabling tests in that it removes the
+/// tests completely.
 void filterTests(testFilter) {
   var filterFunction;
   if (testFilter is String) {
-    RegExp re = new RegExp(testFilter);
+    var re = new RegExp(testFilter);
     filterFunction = (t) => re.hasMatch(t.description);
   } else if (testFilter is RegExp) {
     filterFunction = (t) => testFilter.hasMatch(t.description);
   } else if (testFilter is Function) {
     filterFunction = testFilter;
   }
-  _testCases.retainWhere(filterFunction);
+  environment.testCases.retainWhere(filterFunction);
 }
 
 /// Runs all queued tests, one at a time.
 void runTests() {
   _requireNotRunning();
   _ensureInitialized(false);
-  _environment.currentTestCaseIndex = 0;
-  _config.onStart();
+  environment.currentTestCaseIndex = 0;
+  config.onStart();
   _runTest();
 }
 
-/// Registers that an exception was caught for the current test.
-void registerException(e, [trace]) {
-  _registerException(currentTestCase, e, trace);
-}
-
-/// Registers that an exception was caught for the current test.
-void _registerException(TestCase testCase, e, [trace]) {
-  String message = (e is TestFailure) ? e.message : 'Caught $e';
-  if (testCase.result == null) {
-    testCase._fail(message, trace);
-  } else {
-    testCase._error(message, trace);
-  }
-}
+/// Registers an exception that was caught for the current test.
+void registerException(error, [StackTrace stackTrace]) =>
+    _currentTestCase.registerException(error, stackTrace);
 
 /// Runs the next test.
 void _runTest() {
-  if (_environment.currentTestCaseIndex >= testCases.length) {
-    assert(_environment.currentTestCaseIndex == testCases.length);
+  if (environment.currentTestCaseIndex >= testCases.length) {
+    assert(environment.currentTestCaseIndex == testCases.length);
     _completeTests();
-  } else {
-    var testCase = testCases[_environment.currentTestCaseIndex];
-    Future f = runZoned(testCase._run, onError: (error, stack) {
-      // TODO(kevmoo) Do a better job of flagging these are async errors.
-      // https://code.google.com/p/dart/issues/detail?id=16530
-      _registerException(testCase, error, stack);
-    });
-
-    var timeout = unittestConfiguration.timeout;
-
-    Timer timer;
-    if (timeout != null) {
-      try {
-        timer = new Timer(timeout, () {
-          testCase._error("Test timed out after ${timeout.inSeconds} seconds.");
-          _nextTestCase();
-        });
-      } on UnsupportedError catch (e) {
-        if (e.message != "Timer greater than 0.") rethrow;
-        // Support running on d8 and jsshell which don't support timers.
-      }
+    return;
+  }
+
+  var testCase = _currentTestCase;
+  var f = runZoned(testCase.run, onError: (error, stack) {
+    // TODO(kevmoo) Do a better job of flagging these are async errors.
+    // https://code.google.com/p/dart/issues/detail?id=16530
+    testCase.registerException(error, stack);
+  });
+
+  var timer;
+  var timeout = unittestConfiguration.timeout;
+  if (timeout != null) {
+    try {
+      timer = new Timer(timeout, () {
+        testCase.error("Test timed out after ${timeout.inSeconds} seconds.");
+        _nextTestCase();
+      });
+    } on UnsupportedError catch (e) {
+      if (e.message != "Timer greater than 0.") rethrow;
+      // Support running on d8 and jsshell which don't support timers.
     }
-    f.whenComplete(() {
-      if (timer != null) timer.cancel();
-      var now = new DateTime.now().millisecondsSinceEpoch;
-      if ((now - _environment.lastBreath) >= BREATH_INTERVAL) {
-        _environment.lastBreath = now;
-        Timer.run(_nextTestCase);
-      } else {
-        scheduleMicrotask(_nextTestCase); // Schedule the next test.
-      }
-    });
-  }
-}
-
-/// Publish results on the page and notify controller.
+  }
+
+  f.whenComplete(() {
+    if (timer != null) timer.cancel();
+    var now = new DateTime.now().millisecondsSinceEpoch;
+    if (now - environment.lastBreath >= BREATH_INTERVAL) {
+      environment.lastBreath = now;
+      Timer.run(_nextTestCase);
+    } else {
+      scheduleMicrotask(_nextTestCase); // Schedule the next test.
+    }
+  });
+}
+
+/// Notify the configuration that the testing has finished.
 void _completeTests() {
-  if (!_environment.initialized) return;
-  int passed = 0;
-  int failed = 0;
-  int errors = 0;
-
-  for (TestCase t in testCases) {
-    switch (t.result) {
+  if (!environment.initialized) return;
+
+  var passed = 0;
+  var failed = 0;
+  var errors = 0;
+  for (var testCase in testCases) {
+    switch (testCase.result) {
       case PASS:  passed++; break;
       case FAIL:  failed++; break;
       case ERROR: errors++; break;
     }
   }
-  _config.onSummary(passed, failed, errors, testCases,
-      _environment.uncaughtErrorMessage);
-  _config.onDone(passed > 0 && failed == 0 && errors == 0 &&
-      _environment.uncaughtErrorMessage == null);
-  _environment.initialized = false;
-  _environment.currentTestCaseIndex = -1;
-}
-
-String _fullSpec(String spec) {
-  var group = '${_environment.currentContext.fullName}';
-  if (spec == null) return group;
-  return group != '' ? '$group$groupSep$spec' : spec;
-}
-
-/// Lazily initializes the test library if not already initialized.
+
+  config.onSummary(passed, failed, errors, testCases,
+      environment.uncaughtErrorMessage);
+  config.onDone(passed > 0 && failed == 0 && errors == 0 &&
+      environment.uncaughtErrorMessage == null);
+  environment.initialized = false;
+  environment.currentTestCaseIndex = -1;
+}
+
+/// Initializes the test environment if it hasn't already been initialized.
 void ensureInitialized() {
   _ensureInitialized(true);
 }
 
+/// Initializes the test environment.
+///
+/// If [configAutoStart] is `true`, schedule a microtask to run the tests. This
+/// microtask is expected to run after all the tests are defined.
 void _ensureInitialized(bool configAutoStart) {
-  if (_environment.initialized) {
-    return;
-  }
-  _environment.initialized = true;
+  if (environment.initialized) return;
+
+  environment.initialized = true;
   // Hook our async guard into the matcher library.
   wrapAsync = (f, [id]) => expectAsync(f, id: id);
 
-  _environment.uncaughtErrorMessage = null;
+  environment.uncaughtErrorMessage = null;
 
   unittestConfiguration.onInit();
 
-  if (configAutoStart && _config.autoStart) {
-    // Immediately queue the suite up. It will run after a timeout (i.e. after
-    // main() has returned).
-    scheduleMicrotask(runTests);
-  }
-}
-
-/// Select a solo test by ID.
-void setSoloTest(int id) => _testCases.retainWhere((t) => t.id == id);
-
-/// Enable/disable a test by ID.
-void _setTestEnabledState(int testId, bool state) {
+  // Immediately queue the suite up. It will run after a timeout (i.e. after
+  // main() has returned).
+  if (configAutoStart && config.autoStart) scheduleMicrotask(runTests);
+}
+
+/// Remove all tests other than the one identified by [id].
+void setSoloTest(int id) =>
+    environment.testCases.retainWhere((t) => t.id == id);
+
+/// Enable the test identified by [id].
+void enableTest(int id) => _setTestEnabledState(id, enable: true);
+
+/// Disable the test by [id].
+void disableTest(int id) => _setTestEnabledState(id, enable: false);
+
+/// Enable or disable the test identified by [id].
+void _setTestEnabledState(int id, {bool enable: true}) {
   // Try fast path first.
-  if (testCases.length > testId && testCases[testId].id == testId) {
-    testCases[testId]._enabled = state;
+  if (testCases.length > id && testCases[id].id == id) {
+    environment.testCases[id].enabled = enable;
   } else {
     for (var i = 0; i < testCases.length; i++) {
-      if (testCases[i].id == testId) {
-        testCases[i]._enabled = state;
-        break;
-      }
+      if (testCases[i].id != id) continue;
+      environment.testCases[i].enabled = enable;
+      break;
     }
   }
 }
 
-/// Enable a test by ID.
-void enableTest(int testId) => _setTestEnabledState(testId, true);
-
-/// Disable a test by ID.
-void disableTest(int testId) => _setTestEnabledState(testId, false);
-
-/// Signature for a test function.
-typedef dynamic TestFunction();
-
-/// A flag that controls whether we hide unittest and core library details in
-/// exception stacks.
-///
-/// Useful to disable when debugging unittest or matcher customizations.
-bool formatStacks = true;
-
-/// A flag that controls whether we try to filter out irrelevant frames from
-/// the stack trace.
-///
-/// Requires [formatStacks] to be set.
-bool filterStacks = true;
-
+/// Throws a [StateError] if tests are running.
 void _requireNotRunning() {
-  if (_environment.currentTestCaseIndex != -1) {
-    throw new StateError('Not allowed when tests are running.');
-  }
-}
-
-/// Method to create a test environment running in its own zone scope.
+  if (environment.currentTestCaseIndex == -1) return;
+  throw new StateError('Not allowed when tests are running.');
+}
+
+/// Creates a test environment running in its own zone scope.
 ///
 /// This allows for multiple invocations of the unittest library in the same
-/// application instance.
-/// This is useful when, for example, creating a test runner application which
-/// needs to create a new pristine test environment on each invocation to run
-/// a given set of test.
-dynamic withTestEnvironment(callback()) {
+/// application instance. This is useful when, for example, creating a test
+/// runner application which needs to create a new pristine test environment on
+/// each invocation to run a given set of tests.
+withTestEnvironment(callback()) {
   return runZoned(callback,
-      zoneValues: {_UNITTEST_ENVIRONMENT: new _TestEnvironment()});
-}
+      zoneValues: {#unittest.environment: new TestEnvironment()});
+}