Add observatory_pub_packages snapshot to third_party

observatory_pub_packages/matcher/src/numeric_matchers.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.
+
+library matcher.numeric_matchers;
+
+import 'interfaces.dart';
+
+/// Returns a matcher which matches if the match argument is greater
+/// than the given [value].
+Matcher greaterThan(value) =>
+  new _OrderingComparison(value, false, false, true, 'a value greater than');
+
+/// Returns a matcher which matches if the match argument is greater
+/// than or equal to the given [value].
+Matcher greaterThanOrEqualTo(value) =>
+  new _OrderingComparison(value, true, false, true,
+      'a value greater than or equal to');
+
+/// Returns a matcher which matches if the match argument is less
+/// than the given [value].
+Matcher lessThan(value) =>
+  new _OrderingComparison(value, false, true, false, 'a value less than');
+
+/// Returns a matcher which matches if the match argument is less
+/// than or equal to the given [value].
+Matcher lessThanOrEqualTo(value) =>
+  new _OrderingComparison(value, true, true, false,
+      'a value less than or equal to');
+
+/// A matcher which matches if the match argument is zero.
+const Matcher isZero =
+  const _OrderingComparison(0, true, false, false, 'a value equal to');
+
+
+/// A matcher which matches if the match argument is non-zero.
+const Matcher isNonZero =
+  const _OrderingComparison(0, false, true, true, 'a value not equal to');
+
+/// A matcher which matches if the match argument is positive.
+const Matcher isPositive =
+  const _OrderingComparison(0, false, false, true, 'a positive value', false);
+
+/// A matcher which matches if the match argument is zero or negative.
+const Matcher isNonPositive =
+  const _OrderingComparison(0, true, true, false,
+      'a non-positive value', false);
+
+/// A matcher which matches if the match argument is negative.
+const Matcher isNegative =
+  const _OrderingComparison(0, false, true, false, 'a negative value', false);
+
+/// A matcher which matches if the match argument is zero or positive.
+const Matcher isNonNegative =
+  const _OrderingComparison(0, true, false, true,
+      'a non-negative value', false);
+
+bool _isNumeric(value) {
+  return value is num;
+}
+
+// TODO(kevmoo) Note that matchers that use _OrderingComparison only use
+// `==` and `<` operators to evaluate the match. Or change the matcher.
+class _OrderingComparison extends Matcher {
+  /// Expected value.
+  final _value;
+  /// What to return if actual == expected
+  final bool _equalValue;
+  /// What to return if actual < expected
+  final bool _lessThanValue;
+  /// What to return if actual > expected
+  final bool _greaterThanValue;
+  /// Textual name of the inequality
+  final String _comparisonDescription;
+  /// Whether to include the expected value in the description
+  final bool _valueInDescription;
+
+  const _OrderingComparison(
+    this._value,
+    this._equalValue,
+    this._lessThanValue,
+    this._greaterThanValue,
+    this._comparisonDescription,
+    [bool valueInDescription = true]) :
+      this._valueInDescription = valueInDescription;
+
+  bool matches(item, Map matchState) {
+    if (item == _value) {
+      return _equalValue;
+    } else if (item < _value) {
+      return _lessThanValue;
+    } else {
+      return _greaterThanValue;
+    }
+  }
+
+  Description describe(Description description) {
+    if (_valueInDescription) {
+      return description.add(_comparisonDescription).add(' ').
+          addDescriptionOf(_value);
+    } else {
+      return description.add(_comparisonDescription);
+    }
+  }
+
+  Description describeMismatch(item, Description mismatchDescription,
+                               Map matchState, bool verbose) {
+    mismatchDescription.add('is not ');
+    return describe(mismatchDescription);
+  }
+}
+
+/// Returns a matcher which matches if the match argument is within [delta]
+/// of some [value].
+///
+/// In other words, this matches if the match argument is greater than
+/// than or equal [value]-[delta] and less than or equal to [value]+[delta].
+Matcher closeTo(num value, num delta) => new _IsCloseTo(value, delta);
+
+class _IsCloseTo extends Matcher {
+  final num _value, _delta;
+
+  const _IsCloseTo(this._value, this._delta);
+
+  bool matches(item, Map matchState) {
+    if (!_isNumeric(item)) {
+      return false;
+    }
+    var diff = item - _value;
+    if (diff < 0) diff = -diff;
+    return (diff <= _delta);
+  }
+
+  Description describe(Description description) =>
+    description.add('a numeric value within ').
+        addDescriptionOf(_delta).
+        add(' of ').
+        addDescriptionOf(_value);
+
+  Description describeMismatch(item, Description mismatchDescription,
+                               Map matchState, bool verbose) {
+    if (item is !num) {
+      return mismatchDescription.add(' not numeric');
+    } else {
+      var diff = item - _value;
+      if (diff < 0) diff = -diff;
+      return mismatchDescription.
+          add(' differs by ').
+          addDescriptionOf(diff);
+    }
+  }
+}
+
+/// Returns a matcher which matches if the match argument is greater
+/// than or equal to [low] and less than or equal to [high].
+Matcher inInclusiveRange(num low, num high) =>
+    new _InRange(low, high, true, true);
+
+/// Returns a matcher which matches if the match argument is greater
+/// than [low] and less than [high].
+Matcher inExclusiveRange(num low, num high) =>
+    new _InRange(low, high, false, false);
+
+/// Returns a matcher which matches if the match argument is greater
+/// than [low] and less than or equal to [high].
+Matcher inOpenClosedRange(num low, num high) =>
+    new _InRange(low, high, false, true);
+
+/// Returns a matcher which matches if the match argument is greater
+/// than or equal to a [low] and less than [high].
+Matcher inClosedOpenRange(num low, num high) =>
+    new _InRange(low, high, true, false);
+
+class _InRange extends Matcher {
+  final num _low, _high;
+  final bool _lowMatchValue, _highMatchValue;
+
+  const _InRange(this._low, this._high,
+    this._lowMatchValue, this._highMatchValue);
+
+  bool matches(value, Map matchState) {
+    if (value is! num) {
+      return false;
+    }
+    if (value < _low || value > _high) {
+      return false;
+    }
+    if (value == _low) {
+      return _lowMatchValue;
+    }
+    if (value == _high) {
+      return _highMatchValue;
+    }
+    return true;
+  }
+
+  Description describe(Description description) =>
+      description.add("be in range from "
+        "$_low (${_lowMatchValue ? 'inclusive' : 'exclusive'}) to "
+        "$_high (${_highMatchValue ? 'inclusive' : 'exclusive'})");
+
+  Description describeMismatch(item, Description mismatchDescription,
+                               Map matchState, bool verbose) {
+    if (item is !num) {
+      return mismatchDescription.
+          addDescriptionOf(item).
+          add(' not numeric');
+    } else {
+      return super.describeMismatch(item, mismatchDescription,
+          matchState, verbose);
+    }
+  }
+}