// 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).
 *
 * **See also:**
 * [Unit Testing with Dart]
 * (http://www.dartlang.org/articles/dart-unit-tests/)
 *
 * ##Concepts
 *
 *  * __Tests__: Tests are specified via the top-level function [test], they can be
 *    organized together using [group].
 *
 *  * __Checks__: Test expectations can be specified via [expect]
 *
 *  * __Matchers__: [expect] assertions are written declaratively using the
 *    [Matcher] class.
 *
 *  * __Configuration__: The framework can be adapted by setting
 *    [unittestConfiguration] with a [Configuration]. See the other libraries
 *    in the `unittest` package for alternative implementations of
 *    [Configuration] including `compact_vm_config.dart`, `html_config.dart` and
 *    `html_enhanced_config.dart`.
 *
 * ##Examples
 *
 * A trivial test:
 *
 *     import 'package:unittest/unittest.dart';
 *     main() {
 *       test('this is a test', () {
 *         int x = 2 + 3;
 *         expect(x, equals(5));
 *       });
 *     }
 *
 * Multiple tests:
 *
 *     import 'package:unittest/unittest.dart';
 *     main() {
 *       test('this is a test', () {
 *         int x = 2 + 3;
 *         expect(x, equals(5));
 *       });
 *       test('this is another test', () {
 *         int x = 2 + 3;
 *         expect(x, equals(5));
 *       });
 *     }
 *
 * Multiple tests, grouped by category:
 *
 *     import 'package:unittest/unittest.dart';
 *     main() {
 *       group('group A', () {
 *         test('test A.1', () {
 *           int x = 2 + 3;
 *           expect(x, equals(5));
 *         });
 *         test('test A.2', () {
 *           int x = 2 + 3;
 *           expect(x, equals(5));
 *         });
 *       });
 *       group('group B', () {
 *         test('this B.1', () {
 *           int x = 2 + 3;
 *           expect(x, equals(5));
 *         });
 *       });
 *     }
 *
 * Asynchronous tests: if callbacks expect between 0 and 2 positional arguments,
 * depending on the suffix of expectAsyncX(). expectAsyncX() will wrap a
 * function into a new callback and will not consider the test complete until
 * that callback is run. A count argument can be provided to specify the number
 * of times the callback should be called (the default is 1).
 *
 *     import 'dart:async';
 *     import 'package:unittest/unittest.dart';
 *     void main() {
 *       test('callback is executed once', () {
 *         // wrap the callback of an asynchronous call with [expectAsync0] if
 *         // the callback takes 0 arguments...
 *         var timer = Timer.run(expectAsync0(() {
 *           int x = 2 + 3;
 *           expect(x, equals(5));
 *         }));
 *       });
 *
 *       test('callback is executed twice', () {
 *         var callback = expectAsync0(() {
 *           int x = 2 + 3;
 *           expect(x, equals(5));
 *         }, count: 2); // <-- we can indicate multiplicity to [expectAsync0]
 *         Timer.run(callback);
 *         Timer.run(callback);
 *       });
 *     }
 *
 * expectAsyncX() will wrap the callback code and block the completion of the
 * test until the wrapped callback has been called the specified number of times
 * -- the default is 1. There may be times when the number of times a callback
 * should be called is non-deterministic. In this case a dummy callback can be
 * created with expectAsync0((){}) and this can be called from the real callback
 * when it is finally complete.
 *
 * A variation on this is expectAsyncUntilX(), which takes a callback as the
 * first parameter and a predicate function as the second parameter; after each
 * time * the callback is called, the predicate function will be called; if it
 * returns false the test will still be considered incomplete.
 *
 * Test functions can return [Future]s, which provide another way of doing
 * asynchronous tests. The test framework will handle exceptions thrown by
 * the Future, and will advance to the next test when the Future is complete.
 *
 *     import 'dart:async';
 *     import 'package:unittest/unittest.dart';
 *     void main() {
 *       test('test that time has passed', () {
 *         var duration = const Duration(milliseconds: 200);
 *         var time = new DateTime.now();
 *
 *         return new Future.delayed(duration).then((_) {
 *           var delta = new DateTime.now().difference(time);
 *
 *           expect(delta, greaterThanOrEqualTo(duration));
 *         });
 *       });
 *     }
 *
 * Note: Due to some language limitations we have to use different functions
 * depending on the number of positional arguments of the callback. In the
 * future, we plan to expose a single `expectAsync` function that can be used
 * regardless of the number of positional arguments. This requires new langauge
 * features or fixes to the current spec (e.g. see
 * [Issue 2706](http://dartbug.com/2706)).
 */
library unittest;

import 'dart:async';
import 'dart:collection';
import 'dart:isolate';
import 'package:stack_trace/stack_trace.dart';

import 'matcher.dart';
export 'matcher.dart';

import 'src/utils.dart';

part 'src/configuration.dart';
part 'src/group_context.dart';
part 'src/simple_configuration.dart';
part 'src/spread_args_helper.dart';
part 'src/test_case.dart';

Configuration _config;

/**
 * [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;
}

/**
 * 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) {
      throw new StateError('unittestConfiguration has already been set');
    }
    _config = value;
  }
}

/**
 * Can be called by tests to log status. 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 = ' ';

final List<TestCase> _testCases = new List<TestCase>();

/** Tests executed in this suite. */
final List<TestCase> testCases = new UnmodifiableListView<TestCase>(_testCases);

/**
 * Interval (in msecs) after which synchronous tests will insert an async
 * delay to allow DOM or other updates.
 */
const int BREATH_INTERVAL = 200;

/**
 * The set of tests to run can be restricted by using [solo_test] and
 * [solo_group].
 * As groups can be nested we use a counter to keep track of the nest level
 * of soloing, and a flag to tell if we have seen any solo tests.
 */
int _soloNestingLevel = 0;
bool _soloTestSeen = false;

// We use a 'dummy' context for the top level to eliminate null
// checks when querying the context. This allows us to easily
//  support top-level setUp/tearDown functions as well.
final _rootContext = new _GroupContext();
_GroupContext _currentContext = _rootContext;

/**
 * Represents the index of the currently running test case
 * == -1 implies the test system is not running
 * == [number of test cases] is a short-lived state flagging that the last test
 *    has completed
 */
int _currentTestCaseIndex = -1;

/** [TestCase] currently being executed. */
TestCase get currentTestCase =>
    (_currentTestCaseIndex >= 0 && _currentTestCaseIndex < testCases.length)
        ? testCases[_currentTestCaseIndex]
        : null;

/** Whether the framework is in an initialized state. */
bool _initialized = false;

String _uncaughtErrorMessage = null;

/** Time since we last gave non-sync code a chance to be scheduled. */
int _lastBreath = new DateTime.now().millisecondsSinceEpoch;

/* 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.
const PASS = 'pass';
/// Result string for a failing test case.
const FAIL = 'fail';
/// 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) {
  _requireNotRunning();
  ensureInitialized();
  if (!_soloTestSeen || _soloNestingLevel > 0) {
    var testcase = new TestCase._internal(testCases.length + 1, _fullSpec(spec),
                                        body);
    _testCases.add(testcase);
  }
}

/** 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.
 */
void solo_test(String spec, TestFunction body) {
  _requireNotRunning();
  ensureInitialized();
  if (!_soloTestSeen) {
    _soloTestSeen = true;
    // This is the first solo-ed test. Discard all tests up to now.
    _testCases.clear();
  }
  ++_soloNestingLevel;
  try {
    test(spec, body);
  } finally {
    --_soloNestingLevel;
  }
}

/**
 * Indicate that [callback] is expected to be called a [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.
 */
Function expectAsync(Function callback,
    {int count: 1, int max: 0, String id}) =>
  new _SpreadArgsHelper(callback, count, max, id).func;

/**
 * *Deprecated*
 *
 * Use [expectAsync] instead.
 */
@deprecated
Function expectAsync0(Function callback,
                     {int count: 1, int max: 0, String id}) =>
    expectAsync(callback, count: count, max: max, id: id);

/**
 * *Deprecated*
 *
 * Use [expectAsync] instead.
 */
@deprecated
Function expectAsync1(Function callback,
                     {int count: 1, int max: 0, String id}) =>
    expectAsync(callback, count: count, max: max, id: id);

/**
 * *Deprecated*
 *
 * Use [expectAsync] instead.
 */
@deprecated
Function expectAsync2(Function callback,
                     {int count: 1, int max: 0, String id}) =>
    expectAsync(callback, count: count, max: max, id: id);

/**
 * Indicate that [callback] is expected to be called until [isDone] returns
 * true. The unittest framework check [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).
 */
Function expectAsyncUntil(Function callback, bool isDone(), {String id}) =>
    new _SpreadArgsHelper(callback, 0, -1, id, isDone: isDone).func;

/**
 * *Deprecated*
 *
 * Use [expectAsyncUntil] instead.
 */
@deprecated
Function expectAsyncUntil0(Function callback, Function isDone, {String id}) =>
    expectAsyncUntil(callback, isDone, id: id);

/**
 * *Deprecated*
 *
 * Use [expectAsyncUntil] instead.
 */
@deprecated
Function expectAsyncUntil1(Function callback, Function isDone, {String id}) =>
    expectAsyncUntil(callback, isDone, id: id);

/**
 * *Deprecated*
 *
 * Use [expectAsyncUntil] instead.
 */
@deprecated
Function expectAsyncUntil2(Function callback, Function isDone, {String id}) =>
    expectAsyncUntil(callback, isDone, id: id);

/**
 * *Deprecated*
 *
 * All tests are now run an isolated [Zone].
 *
 * You can safely remove calls to this method.
 */
@deprecated
Function protectAsync0(Function callback, {String id}) {
  return callback;
}

/**
 * *Deprecated*
 *
 * All tests are now run an isolated [Zone].
 *
 * You can safely remove calls to this method.
 */
@deprecated
Function protectAsync1(Function callback, {String id}) {
  return callback;
}

/**
 * *Deprecated*
 *
 * All tests are now run an isolated [Zone].
 *
 * You can safely remove calls to this method.
 */
@deprecated
Function protectAsync2(Function callback, {String id}) {
  return callback;
}

/**
 * Creates a new named group of tests. Calls to group() or test() within the
 * body of the function passed to this will inherit this group's description.
 */
void group(String description, void body()) {
  ensureInitialized();
  _requireNotRunning();
  _currentContext = new _GroupContext(_currentContext, description);
  try {
    body();
  } catch (e, trace) {
    var stack = (trace == null) ? '' : ': ${trace.toString()}';
    _uncaughtErrorMessage = "${e.toString()}$stack";
  } finally {
    // Now that the group is over, restore the previous one.
    _currentContext = _currentContext.parent;
  }
}

/** Like [skip_test], but for groups. */
void skip_group(String description, void body()) {}

/** Like [solo_test], but for groups. */
void solo_group(String description, void body()) {
  _requireNotRunning();
  ensureInitialized();
  if (!_soloTestSeen) {
    _soloTestSeen = true;
    // This is the first solo-ed group. Discard all tests up to now.
    _testCases.clear();
  }
  ++_soloNestingLevel;
  try {
    group(description, body);
  } finally {
    --_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();
  _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();
  _currentContext.testTeardown = teardownTest;
}

/** Advance to the next test case. */
void _nextTestCase() {
  _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]) {
  var msg = '$message\nCaught $e';

  if (currentTestCase != null) {
    currentTestCase._error(msg, stack);
  } else {
    _uncaughtErrorMessage = "$msg: $stack";
  }
}

/**
 * Filter the tests. [testFilter] can be a [RegExp], a [String] or a
 * predicate function. This is different to enabling/disabling tests
 * in that it removes the tests completely.
 */
void filterTests(testFilter) {
  var filterFunction;
  if (testFilter is String) {
    RegExp 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);
}

/** Runs all queued tests, one at a time. */
void runTests() {
  _requireNotRunning();
  _ensureInitialized(false);
  _currentTestCaseIndex = 0;
  _config.onStart();
  _runTest();
}

/**
 * *Deprecated*
 *
 * All tests are now run an isolated [Zone].
 *
 * You can safely remove calls to this method.
 */
@deprecated
guardAsync(Function tryBody) {
  return tryBody();
}

/**
 * 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);
  }
}

/**
 * Runs the next test.
 */
void _runTest() {
  if (_currentTestCaseIndex >= testCases.length) {
    assert(_currentTestCaseIndex == testCases.length);
    _completeTests();
  } else {
    var testCase = testCases[_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.
      }
    }
    f.whenComplete(() {
      if (timer != null) timer.cancel();
      var now = new DateTime.now().millisecondsSinceEpoch;
      if ((now - _lastBreath) >= BREATH_INTERVAL) {
        _lastBreath = now;
        Timer.run(_nextTestCase);
      } else {
        scheduleMicrotask(_nextTestCase); // Schedule the next test.
      }
    });
  }
}

/** Publish results on the page and notify controller. */
void _completeTests() {
  if (!_initialized) return;
  int passed = 0;
  int failed = 0;
  int errors = 0;

  for (TestCase t in testCases) {
    switch (t.result) {
      case PASS:  passed++; break;
      case FAIL:  failed++; break;
      case ERROR: errors++; break;
    }
  }
  _config.onSummary(passed, failed, errors, testCases, _uncaughtErrorMessage);
  _config.onDone(passed > 0 && failed == 0 && errors == 0 &&
      _uncaughtErrorMessage == null);
  _initialized = false;
  _currentTestCaseIndex = -1;
}

String _fullSpec(String spec) {
  var group = '${_currentContext.fullName}';
  if (spec == null) return group;
  return group != '' ? '$group$groupSep$spec' : spec;
}

/**
 * Lazily initializes the test library if not already initialized.
 */
void ensureInitialized() {
  _ensureInitialized(true);
}

void _ensureInitialized(bool configAutoStart) {
  if (_initialized) {
    return;
  }
  _initialized = true;
  // Hook our async guard into the matcher library.
  wrapAsync = (f, [id]) => expectAsync(f, id: id);

  _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) {
  // Try fast path first.
  if (testCases.length > testId && testCases[testId].id == testId) {
    testCases[testId]._enabled = state;
  } else {
    for (var i = 0; i < testCases.length; i++) {
      if (testCases[i].id == testId) {
        testCases[i]._enabled = state;
        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;

void _requireNotRunning() {
  if(_currentTestCaseIndex != -1) {
    throw new StateError('Not allowed when tests are running.');
  }
}

/**
 * Returns a Trace object from a StackTrace object or a String, or the
 * unchanged input if formatStacks is false;
 */
Trace _getTrace(stack) {
  Trace trace;
  if (stack == null || !formatStacks) return null;
  if (stack is String) {
    trace = new Trace.parse(stack);
  } else if (stack is StackTrace) {
    trace = new Trace.from(stack);
  } else {
    throw new Exception('Invalid stack type ${stack.runtimeType} for $stack.');
  }

  if (!filterStacks) return trace;

  // Format the stack trace by removing everything above TestCase._runTest,
  // which is usually going to be irrelevant. Also fold together unittest and
  // core library calls so only the function the user called is visible.
  return new Trace(trace.frames.takeWhile((frame) {
    return frame.package != 'unittest' || frame.member != 'TestCase._runTest';
  })).terse.foldFrames((frame) => frame.package == 'unittest' || frame.isCore);
}