Revert "Remove Expect from core library."

pkg/expect/lib/expect.dart

-// Copyright (c) 2012, 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.
-
-/**
- * This library contains an Expect class with static methods that can be used
- * for simple unit-tests.
- */
-library expect;
-
-/**
- * Expect is used for tests that do not want to make use of the
- * Dart unit test library - for example, the core language tests.
- * Third parties are discouraged from using this, and should use
- * the expect() function in the unit test library instead for
- * test assertions.
- */
-class Expect {
-  /**
-   * Checks whether the expected and actual values are equal (using `==`).
-   */
-  static void equals(var expected, var actual, [String reason = null]) {
-    if (expected == actual) return;
-    String msg = _getMessage(reason);
-    _fail("Expect.equals(expected: <$expected>, actual: <$actual>$msg) fails.");
-  }
-
-  /**
-   * Checks whether the actual value is a bool and its value is true.
-   */
-  static void isTrue(var actual, [String reason = null]) {
-    if (_identical(actual, true)) return;
-    String msg = _getMessage(reason);
-    _fail("Expect.isTrue($actual$msg) fails.");
-  }
-
-  /**
-   * Checks whether the actual value is a bool and its value is false.
-   */
-  static void isFalse(var actual, [String reason = null]) {
-    if (_identical(actual, false)) return;
-    String msg = _getMessage(reason);
-    _fail("Expect.isFalse($actual$msg) fails.");
-  }
-
-  /**
-   * Checks whether [actual] is null.
-   */
-  static void isNull(actual, [String reason = null]) {
-    if (null == actual) return;
-    String msg = _getMessage(reason);
-    _fail("Expect.isNull(actual: <$actual>$msg) fails.");
-  }
-
-  /**
-   * Checks whether [actual] is not null.
-   */
-  static void isNotNull(actual, [String reason = null]) {
-    if (null != actual) return;
-    String msg = _getMessage(reason);
-    _fail("Expect.isNotNull(actual: <$actual>$msg) fails.");
-  }
-
-  /**
-   * Checks whether the expected and actual values are identical
-   * (using `identical`).
-   */
-  static void identical(var expected, var actual, [String reason = null]) {
-    if (_identical(expected, actual)) return;
-    String msg = _getMessage(reason);
-    _fail("Expect.identical(expected: <$expected>, actual: <$actual>$msg) "
-          "fails.");
-  }
-
-  // Unconditional failure.
-  static void fail(String msg) {
-    _fail("Expect.fail('$msg')");
-  }
-
-  /**
-   * Failure if the difference between expected and actual is greater than the
-   * given tolerance. If no tolerance is given, tolerance is assumed to be the
-   * value 4 significant digits smaller than the value given for expected.
-   */
-  static void approxEquals(num expected,
-                           num actual,
-                           [num tolerance = null,
-                            String reason = null]) {
-    if (tolerance == null) {
-      tolerance = (expected / 1e4).abs();
-    }
-    // Note: use !( <= ) rather than > so we fail on NaNs
-    if ((expected - actual).abs() <= tolerance) return;
-
-    String msg = _getMessage(reason);
-    _fail('Expect.approxEquals(expected:<$expected>, actual:<$actual>, '
-          'tolerance:<$tolerance>$msg) fails');
-  }
-
-  static void notEquals(unexpected, actual, [String reason = null]) {
-    if (unexpected != actual) return;
-    String msg = _getMessage(reason);
-    _fail("Expect.notEquals(unexpected: <$unexpected>, actual:<$actual>$msg) "
-          "fails.");
-  }
-
-  /**
-   * Checks that all elements in [expected] and [actual] are equal `==`.
-   * This is different than the typical check for identity equality `identical`
-   * used by the standard list implementation.  It should also produce nicer
-   * error messages than just calling `Expect.equals(expected, actual)`.
-   */
-  static void listEquals(List expected, List actual, [String reason = null]) {
-    String msg = _getMessage(reason);
-    int n = (expected.length < actual.length) ? expected.length : actual.length;
-    for (int i = 0; i < n; i++) {
-      if (expected[i] != actual[i]) {
-        _fail('Expect.listEquals(at index $i, '
-              'expected: <${expected[i]}>, actual: <${actual[i]}>$msg) fails');
-      }
-    }
-    // We check on length at the end in order to provide better error
-    // messages when an unexpected item is inserted in a list.
-    if (expected.length != actual.length) {
-      _fail('Expect.listEquals(list length, '
-        'expected: <${expected.length}>, actual: <${actual.length}>$msg) '
-        'fails: Next element <'
-        '${expected.length > n ? expected[n] : actual[n]}>');
-    }
-  }
-
-  /**
-   * Checks that all [expected] and [actual] have the same set of keys (using
-   * the semantics of [Map.containsKey] to determine what "same" means. For
-   * each key, checks that the values in both maps are equal using `==`.
-   */
-  static void mapEquals(Map expected, Map actual, [String reason = null]) {
-    String msg = _getMessage(reason);
-
-    // Make sure all of the values are present in both and match.
-    for (final key in expected.keys) {
-      if (!actual.containsKey(key)) {
-        _fail('Expect.mapEquals(missing expected key: <$key>$msg) fails');
-      }
-
-      Expect.equals(expected[key], actual[key]);
-    }
-
-    // Make sure the actual map doesn't have any extra keys.
-    for (final key in actual.keys) {
-      if (!expected.containsKey(key)) {
-        _fail('Expect.mapEquals(unexpected key: <$key>$msg) fails');
-      }
-    }
-  }
-
-  /**
-   * Specialized equality test for strings. When the strings don't match,
-   * this method shows where the mismatch starts and ends.
-   */
-  static void stringEquals(String expected,
-                           String actual,
-                           [String reason = null]) {
-    String msg = _getMessage(reason);
-    String defaultMessage =
-        'Expect.stringEquals(expected: <$expected>", <$actual>$msg) fails';
-
-    if (expected == actual) return;
-    if ((expected == null) || (actual == null)) {
-      _fail('$defaultMessage');
-    }
-    // scan from the left until we find a mismatch
-    int left = 0;
-    int eLen = expected.length;
-    int aLen = actual.length;
-    while (true) {
-      if (left == eLen) {
-        assert (left < aLen);
-        String snippet = actual.substring(left, aLen);
-        _fail('$defaultMessage\nDiff:\n...[  ]\n...[ $snippet ]');
-        return;
-      }
-      if (left == aLen) {
-        assert (left < eLen);
-        String snippet = expected.substring(left, eLen);
-        _fail('$defaultMessage\nDiff:\n...[  ]\n...[ $snippet ]');
-        return;
-      }
-      if (expected[left] != actual[left]) {
-        break;
-      }
-      left++;
-    }
-
-    // scan from the right until we find a mismatch
-    int right = 0;
-    while (true) {
-      if (right == eLen) {
-        assert (right < aLen);
-        String snippet = actual.substring(0, aLen - right);
-        _fail('$defaultMessage\nDiff:\n[  ]...\n[ $snippet ]...');
-        return;
-      }
-      if (right == aLen) {
-        assert (right < eLen);
-        String snippet = expected.substring(0, eLen - right);
-        _fail('$defaultMessage\nDiff:\n[  ]...\n[ $snippet ]...');
-        return;
-      }
-      // stop scanning if we've reached the end of the left-to-right match
-      if (eLen - right <= left || aLen - right <= left) {
-        break;
-      }
-      if (expected[eLen - right - 1] != actual[aLen - right - 1]) {
-        break;
-      }
-      right++;
-    }
-    String eSnippet = expected.substring(left, eLen - right);
-    String aSnippet = actual.substring(left, aLen - right);
-    String diff = '\nDiff:\n...[ $eSnippet ]...\n...[ $aSnippet ]...';
-    _fail('$defaultMessage$diff');
-  }
-
-  /**
-   * Checks that every element of [expected] is also in [actual], and that
-   * every element of [actual] is also in [expected].
-   */
-  static void setEquals(Iterable expected,
-                        Iterable actual,
-                        [String reason = null]) {
-    final missingSet = new Set.from(expected);
-    missingSet.removeAll(actual);
-    final extraSet = new Set.from(actual);
-    extraSet.removeAll(expected);
-
-    if (extraSet.isEmpty && missingSet.isEmpty) return;
-    String msg = _getMessage(reason);
-
-    StringBuffer sb = new StringBuffer("Expect.setEquals($msg) fails");
-    // Report any missing items.
-    if (!missingSet.isEmpty) {
-      sb.write('\nExpected collection does not contain: ');
-    }
-
-    for (final val in missingSet) {
-      sb.write('$val ');
-    }
-
-    // Report any extra items.
-    if (!extraSet.isEmpty) {
-      sb.write('\nExpected collection should not contain: ');
-    }
-
-    for (final val in extraSet) {
-      sb.write('$val ');
-    }
-    _fail(sb.toString());
-  }
-
-  /**
-   * Calls the function [f] and verifies that it throws an exception.
-   * The optional [check] function can provide additional validation
-   * that the correct exception is being thrown.  For example, to check
-   * the type of the exception you could write this:
-   *
-   *     Expect.throws(myThrowingFunction, (e) => e is MyException);
-   */
-  static void throws(void f(),
-                     [_CheckExceptionFn check = null,
-                      String reason = null]) {
-    try {
-      f();
-    } catch (e, s) {
-      if (check != null) {
-        if (!check(e)) {
-          String msg = reason == null ? "" : reason;
-          _fail("Expect.throws($msg): Unexpected '$e'\n$s");
-        }
-      }
-      return;
-    }
-    String msg = reason == null ? "" : reason;
-    _fail('Expect.throws($msg) fails');
-  }
-
-  static String _getMessage(String reason)
-      => (reason == null) ? "" : ", '$reason'";
-
-  static void _fail(String message) {
-    throw new ExpectException(message);
-  }
-}
-
-bool _identical(a, b) => identical(a, b);
-
-typedef bool _CheckExceptionFn(exception);
-
-class ExpectException implements Exception {
-  ExpectException(this.message);
-  String toString() => message;
-  String message;
-}