Restructure pkg/unittest and pkg/webdriver to follow the pub conventions.

pkg/unittest/lib/mock.dart

Index: pkg/unittest/lib/mock.dart
===================================================================
--- pkg/unittest/lib/mock.dart	(revision 0)
+++ pkg/unittest/lib/mock.dart	(revision 0)
@@ -0,0 +1,1466 @@
+// 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.
+
+// TODO(gram) - when we can do package imports from within packages
+// without Dartdoc choking, this should be moved to a separate package.

[Siggi Cherem (dart-lang), 2012/10/31 20:54:02]

same question as before

[gram, 2012/11/01 21:23:19]

Done.

+
+library mock;
+import 'matcher.dart';
+
+/**
+ * The error formatter for mocking is a bit different from the default one
+ * for unit testing; instead of the third argument being a 'reason'
+ * it is instead a [signature] describing the method signature filter
+ * that was used to select the logs that were verified.
+ */
+String _mockingErrorFormatter(actual, Matcher matcher, String signature,
+                              MatchState matchState, bool verbose) {
+  var description = new StringDescription();
+  description.add('Expected ${signature} ').addDescriptionOf(matcher).
+      add('\n     but: ');
+  matcher.describeMismatch(actual, description, matchState, verbose).add('.');
+  return description.toString();
+}
+
+/**
+ * The failure handler for the [expect()] calls that occur in [verify()]
+ * methods in the mock objects. This calls the real failure handler used
+ * by the unit test library after formatting the error message with
+ * the custom formatter.
+ */
+class _MockFailureHandler implements FailureHandler {
+  FailureHandler proxy;
+  _MockFailureHandler(this.proxy);
+  void fail(String reason) {
+    proxy.fail(reason);
+  }
+  void failMatch(actual, Matcher matcher, String reason,
+                 MatchState matchState, bool verbose) {
+    proxy.fail(_mockingErrorFormatter(actual, matcher, reason,
+        matchState, verbose));
+  }
+}
+
+_MockFailureHandler _mockFailureHandler = null;
+
+/** Sentinel value for representing no argument. */
+class _Sentinel {
+  const _Sentinel();
+}
+const _noArg = const _Sentinel();
+
+/** The ways in which a call to a mock method can be handled. */
+class Action {
+  /** Do nothing (void method) */
+  static const IGNORE = const Action._('IGNORE');
+
+  /** Return a supplied value. */
+  static const RETURN = const Action._('RETURN');
+
+  /** Throw a supplied value. */
+  static const THROW = const Action._('THROW');
+
+  /** Call a supplied function. */
+  static const PROXY = const Action._('PROXY');
+
+  const Action._(this.name);
+
+  final String name;
+}
+
+/**
+ * The behavior of a method call in the mock library is specified
+ * with [Responder]s. A [Responder] has a [value] to throw
+ * or return (depending on the type of [action]),
+ * and can either be one-shot, multi-shot, or infinitely repeating,
+ * depending on the value of [count (1, greater than 1, or 0 respectively).
+ */
+class Responder {
+  var value;
+  Action action;
+  int count;
+  Responder(this.value, [this.count = 1, this.action = Action.RETURN]);
+}
+
+/**
+ * A [CallMatcher] is a special matcher used to match method calls (i.e.
+ * a method name and set of arguments). It is not a [Matcher] like the
+ * unit test [Matcher], but instead represents a method name and a
+ * collection of [Matcher]s, one per argument, that will be applied
+ * to the parameters to decide if the method call is a match.
+ */
+class CallMatcher {
+  Matcher nameFilter;
+  List<Matcher> argMatchers;
+
+  /**
+   * Constructor for [CallMatcher]. [name] can be null to
+   * match anything, or a literal [String], a predicate [Function],
+   * or a [Matcher]. The various arguments can be scalar values or
+   * [Matcher]s.
+   */
+  CallMatcher([name,
+              arg0 = _noArg,
+              arg1 = _noArg,
+              arg2 = _noArg,
+              arg3 = _noArg,
+              arg4 = _noArg,
+              arg5 = _noArg,
+              arg6 = _noArg,
+              arg7 = _noArg,
+              arg8 = _noArg,
+              arg9 = _noArg]) {
+    if (name == null) {
+      nameFilter = anything;
+    } else {
+      nameFilter = wrapMatcher(name);
+    }
+    argMatchers = new List<Matcher>();
+    if (arg0 === _noArg) return;
+    argMatchers.add(wrapMatcher(arg0));
+    if (arg1 === _noArg) return;
+    argMatchers.add(wrapMatcher(arg1));
+    if (arg2 === _noArg) return;
+    argMatchers.add(wrapMatcher(arg2));
+    if (arg3 === _noArg) return;
+    argMatchers.add(wrapMatcher(arg3));
+    if (arg4 === _noArg) return;
+    argMatchers.add(wrapMatcher(arg4));
+    if (arg5 === _noArg) return;
+    argMatchers.add(wrapMatcher(arg5));
+    if (arg6 === _noArg) return;
+    argMatchers.add(wrapMatcher(arg6));
+    if (arg7 === _noArg) return;
+    argMatchers.add(wrapMatcher(arg7));
+    if (arg8 === _noArg) return;
+    argMatchers.add(wrapMatcher(arg8));
+    if (arg9 === _noArg) return;
+    argMatchers.add(wrapMatcher(arg9));
+  }
+
+  /**
+   * We keep our behavior specifications in a Map, which is keyed
+   * by the [CallMatcher]. To make the keys unique and to get a
+   * descriptive value for the [CallMatcher] we have this override
+   * of [toString()].
+   */
+  String toString() {
+    Description d = new StringDescription();
+    d.addDescriptionOf(nameFilter);
+    // If the nameFilter was a simple string - i.e. just a method name -
+    // strip the quotes to make this more natural in appearance.
+    if (d.toString()[0] == "'") {
+      d.replace(d.toString().substring(1, d.toString().length - 1));
+    }
+    d.add('(');
+    for (var i = 0; i < argMatchers.length; i++) {
+      if (i > 0) d.add(', ');
+      d.addDescriptionOf(argMatchers[i]);
+    }
+    d.add(')');
+    return d.toString();
+  }
+
+  /**
+   * Given a [method] name and list of [arguments], return true
+   * if it matches this [CallMatcher.
+   */
+  bool matches(String method, List arguments) {
+    var matchState = new MatchState();
+    if (!nameFilter.matches(method, matchState)) {
+      return false;
+    }
+    var numArgs = (arguments == null) ? 0 : arguments.length;
+    if (numArgs < argMatchers.length) {
+      throw new Exception("Less arguments than matchers for $method.");
+    }
+    for (var i = 0; i < argMatchers.length; i++) {
+      if (!argMatchers[i].matches(arguments[i], matchState)) {
+        return false;
+      }
+    }
+    return true;
+  }
+}
+
+/**
+ * Returns a [CallMatcher] for the specified signature. [method] can be
+ * null to match anything, or a literal [String], a predicate [Function],
+ * or a [Matcher]. The various arguments can be scalar values or [Matcher]s.
+ */
+CallMatcher callsTo([method,
+                     arg0 = _noArg,
+                     arg1 = _noArg,
+                     arg2 = _noArg,
+                     arg3 = _noArg,
+                     arg4 = _noArg,
+                     arg5 = _noArg,
+                     arg6 = _noArg,
+                     arg7 = _noArg,
+                     arg8 = _noArg,
+                     arg9 = _noArg]) {
+  return new CallMatcher(method, arg0, arg1, arg2, arg3, arg4,
+      arg5, arg6, arg7, arg8, arg9);
+}
+
+/**
+ * A [Behavior] represents how a [Mock] will respond to one particular
+ * type of method call.
+ */
+class Behavior {
+  CallMatcher matcher; // The method call matcher.
+  List<Responder> actions; // The values to return/throw or proxies to call.
+  bool logging = true;
+
+  Behavior (this.matcher) {
+    actions = new List<Responder>();
+  }
+
+  /**
+   * Adds a [Responder] that returns a [value] for [count] calls
+   * (1 by default).
+   */
+  Behavior thenReturn(value, [count = 1]) {
+    actions.add(new Responder(value, count, Action.RETURN));
+    return this; // For chaining calls.
+  }
+
+  /** Adds a [Responder] that repeatedly returns a [value]. */
+  Behavior alwaysReturn(value) {
+    return thenReturn(value, 0);
+  }
+
+  /**
+   * Adds a [Responder] that throws [value] [count]
+   * times (1 by default).
+   */
+  Behavior thenThrow(value, [count = 1]) {
+    actions.add(new Responder(value, count, Action.THROW));
+    return this; // For chaining calls.
+  }
+
+  /** Adds a [Responder] that throws [value] endlessly. */
+  Behavior alwaysThrow(value) {
+    return thenThrow(value, 0);
+  }
+
+  /**
+   * [thenCall] creates a proxy Responder, that is called [count]
+   * times (1 by default; 0 is used for unlimited calls, and is
+   * exposed as [alwaysCall]). [value] is the function that will
+   * be called with the same arguments that were passed to the
+   * mock. Proxies can be used to wrap real objects or to define
+   * more complex return/throw behavior. You could even (if you
+   * wanted) use proxies to emulate the behavior of thenReturn;
+   * e.g.:
+   *
+   *     m.when(callsTo('foo')).thenReturn(0)
+   *
+   * is equivalent to:
+   *
+   *     m.when(callsTo('foo')).thenCall(() => 0)
+   */
+  Behavior thenCall(value, [count = 1]) {
+    actions.add(new Responder(value, count, Action.PROXY));
+    return this; // For chaining calls.
+  }
+
+  /** Creates a repeating proxy call. */
+  Behavior alwaysCall(value) {
+    return thenCall(value, 0);
+  }
+
+  /** Returns true if a method call matches the [Behavior]. */
+  bool matches(String method, List args) => matcher.matches(method, args);
+
+  /** Returns the [matcher]'s representation. */
+  String toString() => matcher.toString();
+}
+
+/**
+ * Every call to a [Mock] object method is logged. The logs are
+ * kept in instances of [LogEntry].
+ */
+class LogEntry {
+  /** The time of the event. */
+  Date time;
+
+  /** The mock object name, if any. */
+  final String mockName;
+
+  /** The method name. */
+  final String methodName;
+
+  /** The parameters. */
+  final List args;
+
+  /** The behavior that resulted. */
+  final Action action;
+
+  /** The value that was returned (if no throw). */
+  final value;
+
+  LogEntry(this.mockName, this.methodName,
+      this.args, this.action, [this.value]) {
+    time = new Date.now();
+  }
+
+  String _pad2(int val) => (val >= 10 ? '$val' : '0$val');
+
+  String toString([Date baseTime]) {
+    Description d = new StringDescription();
+    if (baseTime == null) {
+      // Show absolute time.
+      d.add('${time.hour}:${_pad2(time.minute)}:'
+          '${_pad2(time.second)}.${time.millisecond}>  ');
+    } else {
+      // Show relative time.
+      int delta = time.millisecondsSinceEpoch - baseTime.millisecondsSinceEpoch;
+      int secs = delta ~/ 1000;
+      int msecs = delta % 1000;
+      d.add('$secs.$msecs>  ');
+    }
+    d.add('${_qualifiedName(mockName, methodName)}(');
+    if (args != null) {
+      for (var i = 0; i < args.length; i++) {
+        if (i != 0) d.add(', ');
+        d.addDescriptionOf(args[i]);
+      }
+    }
+    d.add(') ${action == Action.THROW ? "threw" : "returned"} ');
+    d.addDescriptionOf(value);
+    return d.toString();
+  }
+}
+
+/** Utility function for optionally qualified method names */
+String _qualifiedName(owner, String method) {
+  if (owner == null || owner === anything) {
+    return method;
+  } else if (owner is Matcher) {
+    Description d = new StringDescription();
+    d.addDescriptionOf(owner);
+    d.add('.');
+    d.add(method);
+    return d.toString();
+  } else {
+    return '$owner.$method';
+  }
+}
+
+/**
+* [StepValidator]s are used by [stepwiseValidate] in [LogEntryList], which
+* iterates through the list and call the [StepValidator] function with the
+* log [List] and position. The [StepValidator] should return the number of
+* positions to advance upon success, or zero upon failure. When zero is
+* returned an error is reported.
+*/
+typedef int StepValidator(List<LogEntry> logs, int pos);
+
+/**
+ * We do verification on a list of [LogEntry]s. To allow chaining
+ * of calls to verify, we encapsulate such a list in the [LogEntryList]
+ * class.
+ */
+class LogEntryList {
+  String filter;
+  List<LogEntry> logs;
+  LogEntryList([this.filter]) {
+    logs = new List<LogEntry>();
+  }
+
+  /** Add a [LogEntry] to the log. */
+  add(LogEntry entry) => logs.add(entry);
+
+  /** Get the first entry, or null if no entries. */
+  get first => (logs == null || logs.length == 0) ? null : logs[0];
+
+  /** Get the last entry, or null if no entries. */
+  get last => (logs == null || logs.length == 0) ? null : logs.last;
+
+  /** Creates a LogEntry predicate function from the argument. */
+  Function _makePredicate(arg) {
+    if (arg == null) {
+      return (e) => true;
+    } else if (arg is CallMatcher) {
+      return (e) => arg.matches(e.methodName, e.args);
+    } else if (arg is Function) {
+      return arg;
+    } else {
+      throw new Exception("Invalid argument to _makePredicate.");
+    }
+  }
+
+  /**
+   * Create a new [LogEntryList] consisting of [LogEntry]s from
+   * this list that match the specified [mockNameFilter] and [logFilter].
+   * [mockNameFilter] can be null, a [String], a predicate [Function],
+   * or a [Matcher]. If [mockNameFilter] is null, this is the same as
+   * [anything].
+   * If [logFilter] is null, all entries in the log will be returned.
+   * Otherwise [logFilter] should be a [CallMatcher] or  predicate function
+   * that takes a [LogEntry] and returns a bool.
+   * If [destructive] is true, the log entries are removed from the
+   * original list.
+   */
+  LogEntryList getMatches([mockNameFilter,
+                          logFilter,
+                          Matcher actionMatcher,
+                          bool destructive = false]) {
+    if (mockNameFilter == null) {
+      mockNameFilter = anything;
+    } else {
+      mockNameFilter = wrapMatcher(mockNameFilter);
+    }
+    Function entryFilter = _makePredicate(logFilter);
+    String filterName = _qualifiedName(mockNameFilter, logFilter.toString());
+    LogEntryList rtn = new LogEntryList(filterName);
+    MatchState matchState = new MatchState();
+    for (var i = 0; i < logs.length; i++) {
+      LogEntry entry = logs[i];
+      if (mockNameFilter.matches(entry.mockName, matchState) &&
+          entryFilter(entry)) {
+        if (actionMatcher == null ||
+            actionMatcher.matches(entry, matchState)) {
+          rtn.add(entry);
+          if (destructive) {
+            logs.removeRange(i--, 1);
+          }
+        }
+      }
+    }
+    return rtn;
+  }
+
+  /** Apply a unit test [Matcher] to the [LogEntryList]. */
+  LogEntryList verify(Matcher matcher) {
+    if (_mockFailureHandler == null) {
+      _mockFailureHandler =
+          new _MockFailureHandler(getOrCreateExpectFailureHandler());
+    }
+    expect(logs, matcher, reason:filter, failureHandler: _mockFailureHandler);
+    return this;
+  }
+
+  /**
+   * Iterate through the list and call the [validator] function with the
+   * log [List] and position. The [validator] should return the number of
+   * positions to advance upon success, or zero upon failure. When zero is
+   * returned an error is reported. [reason] can be used to provide a
+   * more descriptive failure message. If a failure occurred false will be
+   * returned (unless the failure handler itself threw an exception);
+   * otherwise true is returned.
+   * The use case here is to perform more complex validations; for example
+   * we may want to assert that the return value from some function is
+   * later used as a parameter to a following function. If we filter the logs
+   * to include just these two functions we can write a simple validator to
+   * do this check.
+   */
+  bool stepwiseValidate(StepValidator validator, [String reason = '']) {
+    if (_mockFailureHandler == null) {
+      _mockFailureHandler =
+          new _MockFailureHandler(getOrCreateExpectFailureHandler());
+    }
+    var i = 0;
+    while (i < logs.length) {
+      var n = validator(logs, i);
+      if (n == 0) {
+        if (reason.length > 0) {
+          reason = ': $reason';
+        }
+        _mockFailureHandler.fail("Stepwise validation failed at $filter "
+                                 "position $i$reason");
+        return false;
+      } else {
+        i += n;
+      }
+    }
+    return true;
+  }
+
+  /**
+   * Turn the logs into human-readable text. If [baseTime] is specified
+   * then each entry is prefixed with the offset from that time in
+   * milliseconds; otherwise the time of day is used.
+   */
+  String toString([Date baseTime]) {
+    String s = '';
+    for (var e in logs) {
+      s = '$s${e.toString(baseTime)}\n';
+    }
+    return s;
+  }
+
+  /**
+   *  Find the first log entry that satisfies [logFilter] and
+   *  return its position. A search [start] position can be provided
+   *  to allow for repeated searches. [logFilter] can be a [CallMatcher],
+   *  or a predicate function that takes a [LogEntry] argument and returns
+   *  a bool. If [logFilter] is null, it will match any [LogEntry].
+   *  If no entry is found, then [failureReturnValue] is returned.
+   *  After each check the position is updated by [skip], so using
+   *  [skip] of -1 allows backward searches, using a [skip] of 2 can
+   *  be used to check pairs of adjacent entries, and so on.
+   */
+  int findLogEntry(logFilter, [int start = 0, int failureReturnValue = -1,
+      skip = 1]) {
+    logFilter = _makePredicate(logFilter);
+    int pos = start;
+    while (pos >= 0 && pos < logs.length) {
+      if (logFilter(logs[pos])) {
+        return pos;
+      }
+      pos += skip;
+    }
+    return failureReturnValue;
+  }
+
+  /**
+   * Returns log events that happened up to the first one that
+   * satisfies [logFilter]. If [inPlace] is true, then returns
+   * this LogEntryList after removing the from the first satisfier;
+   * onwards otherwise a new list is created. [description]
+   * is used to create a new name for the resulting list.
+   * [defaultPosition] is used as the index of the matching item in
+   * the case that no match is found.
+   */
+  LogEntryList _head(logFilter, bool inPlace,
+                     String description, int defaultPosition) {
+    if (filter != null) {
+      description = '$filter $description';
+    }
+    int pos = findLogEntry(logFilter, 0, defaultPosition);
+    if (inPlace) {
+      if (pos < logs.length) {
+        logs.removeRange(pos, logs.length - pos);
+      }
+      filter = description;
+      return this;
+    } else {
+      LogEntryList newList = new LogEntryList(description);
+      for (var i = 0; i < pos; i++) {
+        newList.logs.add(logs[i]);
+      }
+      return newList;
+    }
+  }
+
+  /**
+   * Returns log events that happened from the first one that
+   * satisfies [logFilter]. If [inPlace] is true, then returns
+   * this LogEntryList after removing the entries up to the first
+   * satisfier; otherwise a new list is created. [description]
+   * is used to create a new name for the resulting list.
+   * [defaultPosition] is used as the index of the matching item in
+   * the case that no match is found.
+   */
+  LogEntryList _tail(logFilter, bool inPlace,
+                     String description, int defaultPosition) {
+    if (filter != null) {
+      description = '$filter $description';
+    }
+    int pos = findLogEntry(logFilter, 0, defaultPosition);
+    if (inPlace) {
+      if (pos > 0) {
+        logs.removeRange(0, pos);
+      }
+      filter = description;
+      return this;
+    } else {
+      LogEntryList newList = new LogEntryList(description);
+      while (pos < logs.length) {
+        newList.logs.add(logs[pos++]);
+      }
+      return newList;
+    }
+  }
+
+  /**
+   * Returns log events that happened after [when]. If [inPlace]
+   * is true, then it returns this LogEntryList after removing
+   * the entries that happened up to [when]; otherwise a new
+   * list is created.
+   */
+  LogEntryList after(Date when, [bool inPlace = false]) =>
+      _tail((e) => e.time > when, inPlace, 'after $when', logs.length);
+
+  /**
+   * Returns log events that happened from [when] onwards. If
+   * [inPlace] is true, then it returns this LogEntryList after
+   * removing the entries that happened before [when]; otherwise
+   * a new list is created.
+   */
+  LogEntryList from(Date when, [bool inPlace = false]) =>
+      _tail((e) => e.time >= when, inPlace, 'from $when', logs.length);
+
+  /**
+   * Returns log events that happened until [when]. If [inPlace]
+   * is true, then it returns this LogEntryList after removing
+   * the entries that happened after [when]; otherwise a new
+   * list is created.
+   */
+  LogEntryList until(Date when, [bool inPlace = false]) =>
+      _head((e) => e.time > when, inPlace, 'until $when', logs.length);
+
+  /**
+   * Returns log events that happened before [when]. If [inPlace]
+   * is true, then it returns this LogEntryList after removing
+   * the entries that happened from [when] onwards; otherwise a new
+   * list is created.
+   */
+  LogEntryList before(Date when, [bool inPlace = false]) =>
+      _head((e) => e.time >= when, inPlace, 'before $when', logs.length);
+
+  /**
+   * Returns log events that happened after [logEntry]'s time.
+   * If [inPlace] is true, then it returns this LogEntryList after
+   * removing the entries that happened up to [when]; otherwise a new
+   * list is created. If [logEntry] is null the current time is used.
+   */
+  LogEntryList afterEntry(LogEntry logEntry, [bool inPlace = false]) =>
+      after(logEntry == null ? new Date.now() : logEntry.time);
+
+  /**
+   * Returns log events that happened from [logEntry]'s time onwards.
+   * If [inPlace] is true, then it returns this LogEntryList after
+   * removing the entries that happened before [when]; otherwise
+   * a new list is created. If [logEntry] is null the current time is used.
+   */
+  LogEntryList fromEntry(LogEntry logEntry, [bool inPlace = false]) =>
+      from(logEntry == null ? new Date.now() : logEntry.time);
+
+  /**
+   * Returns log events that happened until [logEntry]'s time. If
+   * [inPlace] is true, then it returns this LogEntryList after removing
+   * the entries that happened after [when]; otherwise a new
+   * list is created. If [logEntry] is null the epoch time is used.
+   */
+  LogEntryList untilEntry(LogEntry logEntry, [bool inPlace = false]) =>
+      until(logEntry == null ?
+          new Date.fromMillisecondsSinceEpoch(0) : logEntry.time);
+
+  /**
+   * Returns log events that happened before [logEntry]'s time. If
+   * [inPlace] is true, then it returns this LogEntryList after removing
+   * the entries that happened from [when] onwards; otherwise a new
+   * list is created. If [logEntry] is null the epoch time is used.
+   */
+  LogEntryList beforeEntry(LogEntry logEntry, [bool inPlace = false]) =>
+      before(logEntry == null ?
+          new Date.fromMillisecondsSinceEpoch(0) : logEntry.time);
+
+  /**
+   * Returns log events that happened after the first event in [segment].
+   * If [inPlace] is true, then it returns this LogEntryList after removing
+   * the entries that happened earlier; otherwise a new list is created.
+   */
+  LogEntryList afterFirst(LogEntryList segment, [bool inPlace = false]) =>
+      afterEntry(segment.first, inPlace);
+
+  /**
+   * Returns log events that happened after the last event in [segment].
+   * If [inPlace] is true, then it returns this LogEntryList after removing
+   * the entries that happened earlier; otherwise a new list is created.
+   */
+  LogEntryList afterLast(LogEntryList segment, [bool inPlace = false]) =>
+      afterEntry(segment.last, inPlace);
+
+  /**
+   * Returns log events that happened from the time of the first event in
+   * [segment] onwards. If [inPlace] is true, then it returns this
+   * LogEntryList after removing the earlier entries; otherwise a new list
+   * is created.
+   */
+  LogEntryList fromFirst(LogEntryList segment, [bool inPlace = false]) =>
+      fromEntry(segment.first, inPlace);
+
+  /**
+   * Returns log events that happened from the time of the last event in
+   * [segment] onwards. If [inPlace] is true, then it returns this
+   * LogEntryList after removing the earlier entries; otherwise a new list
+   * is created.
+   */
+  LogEntryList fromLast(LogEntryList segment, [bool inPlace = false]) =>
+      fromEntry(segment.last, inPlace);
+
+  /**
+   * Returns log events that happened until the first event in [segment].
+   * If [inPlace] is true, then it returns this LogEntryList after removing
+   * the entries that happened later; otherwise a new list is created.
+   */
+  LogEntryList untilFirst(LogEntryList segment, [bool inPlace = false]) =>
+      untilEntry(segment.first, inPlace);
+
+  /**
+   * Returns log events that happened until the last event in [segment].
+   * If [inPlace] is true, then it returns this LogEntryList after removing
+   * the entries that happened later; otherwise a new list is created.
+   */
+  LogEntryList untilLast(LogEntryList segment, [bool inPlace = false]) =>
+      untilEntry(segment.last, inPlace);
+
+  /**
+   * Returns log events that happened before the first event in [segment].
+   * If [inPlace] is true, then it returns this LogEntryList after removing
+   * the entries that happened later; otherwise a new list is created.
+   */
+  LogEntryList beforeFirst(LogEntryList segment, [bool inPlace = false]) =>
+      beforeEntry(segment.first, inPlace);
+
+  /**
+   * Returns log events that happened before the last event in [segment].
+   * If [inPlace] is true, then it returns this LogEntryList after removing
+   * the entries that happened later; otherwise a new list is created.
+   */
+  LogEntryList beforeLast(LogEntryList segment, [bool inPlace = false]) =>
+      beforeEntry(segment.last, inPlace);
+
+  /**
+   * Iterate through the LogEntryList looking for matches to the entries
+   * in [keys]; for each match found the closest [distance] neighboring log
+   * entries that match [mockNameFilter] and [logFilter] will be included in
+   * the result. If [isPreceding] is true we use the neighbors that precede
+   * the matched entry; else we use the neighbors that followed.
+   * If [includeKeys] is true then the entries in [keys] that resulted in
+   * entries in the output list are themselves included in the output list. If
+   * [distance] is zero then all matches are included.
+   */
+  LogEntryList _neighboring(bool isPreceding,
+                            LogEntryList keys,
+                            mockNameFilter,
+                            logFilter,
+                            int distance,
+                            bool includeKeys) {
+    String filterName = 'Calls to '
+        '${_qualifiedName(mockNameFilter, logFilter.toString())} '
+        '${isPreceding?"preceding":"following"} ${keys.filter}';
+
+    LogEntryList rtn = new LogEntryList(filterName);
+
+    // Deal with the trivial case.
+    if (logs.length == 0 || keys.logs.length == 0) {
+      return rtn;
+    }
+
+    // Normalize the mockNameFilter and logFilter values.
+    if (mockNameFilter == null) {
+      mockNameFilter = anything;
+    } else {
+      mockNameFilter = wrapMatcher(mockNameFilter);
+    }
+    logFilter = _makePredicate(logFilter);
+
+    // The scratch list is used to hold matching entries when we
+    // are doing preceding neighbors. The remainingCount is used to
+    // keep track of how many matching entries we can still add in the
+    // current segment (0 if we are doing doing following neighbors, until
+    // we get our first key match).
+    List scratch = null;
+    int remainingCount = 0;
+    if (isPreceding) {
+      scratch = new List();
+      remainingCount = logs.length;
+    }
+
+    var keyIterator = keys.logs.iterator();
+    LogEntry keyEntry = keyIterator.next();
+    MatchState matchState = new MatchState();
+
+    for (LogEntry logEntry in logs) {
+      // If we have a log entry match, copy the saved matches from the
+      // scratch buffer into the return list, as well as the matching entry,
+      // if appropriate, and reset the scratch buffer. Continue processing
+      // from the next key entry.
+      if (keyEntry == logEntry) {
+        if (scratch != null) {
+          int numToCopy = scratch.length;
+          if (distance > 0 && distance < numToCopy) {
+            numToCopy = distance;
+          }
+          for (var i = scratch.length - numToCopy; i < scratch.length; i++) {
+            rtn.logs.add(scratch[i]);
+          }
+          scratch.clear();
+        } else {
+          remainingCount = distance > 0 ? distance : logs.length;
+        }
+        if (includeKeys) {
+          rtn.logs.add(keyEntry);
+        }
+        if (keyIterator.hasNext) {
+          keyEntry = keyIterator.next();
+        } else if (isPreceding) { // We're done.
+          break;
+        }
+      } else if (remainingCount > 0 &&
+                 mockNameFilter.matches(logEntry.mockName, matchState) &&
+                 logFilter(logEntry)) {
+        if (scratch != null) {
+          scratch.add(logEntry);
+        } else {
+          rtn.logs.add(logEntry);
+          --remainingCount;
+        }
+      }
+    }
+    return rtn;
+  }
+
+  /**
+   * Iterate through the LogEntryList looking for matches to the entries
+   * in [keys]; for each match found the closest [distance] prior log entries
+   * that match [mocknameFilter] and [logFilter] will be included in the result.
+   * If [includeKeys] is true then the entries in [keys] that resulted in
+   * entries in the output list are themselves included in the output list. If
+   * [distance] is zero then all matches are included.
+   *
+   * The idea here is that you could find log entries that are related to
+   * other logs entries in some temporal sense. For example, say we have a
+   * method commit() that returns -1 on failure. Before commit() gets called
+   * the value being committed is created by process(). We may want to find
+   * the calls to process() that preceded calls to commit() that failed.
+   * We could do this with:
+   *
+   *      print(log.preceding(log.getLogs(callsTo('commit'), returning(-1)),
+   *          logFilter: callsTo('process')).toString());
+   *
+   * We might want to include the details of the failing calls to commit()
+   * to see what parameters were passed in, in which case we would set
+   * [includeKeys].
+   *
+   * As another simple example, say we wanted to know the three method
+   * calls that immediately preceded each failing call to commit():
+   *
+   *     print(log.preceding(log.getLogs(callsTo('commit'), returning(-1)),
+   *         distance: 3).toString());
+   */
+  LogEntryList preceding(LogEntryList keys,
+                         {mockNameFilter: null,
+                         logFilter: null,
+                         int distance: 1,
+                         bool includeKeys: false}) =>
+      _neighboring(true, keys, mockNameFilter, logFilter,
+          distance, includeKeys);
+
+  /**
+   * Iterate through the LogEntryList looking for matches to the entries
+   * in [keys]; for each match found the closest [distance] subsequent log
+   * entries that match [mocknameFilter] and [logFilter] will be included in
+   * the result. If [includeKeys] is true then the entries in [keys] that
+   * resulted in entries in the output list are themselves included in the
+   * output list. If [distance] is zero then all matches are included.
+   * See [preceding] for a usage example.
+   */
+  LogEntryList following(LogEntryList keys,
+                         {mockNameFilter: null,
+                         logFilter: null,
+                         int distance: 1,
+                         bool includeKeys: false}) =>
+      _neighboring(false, keys, mockNameFilter, logFilter,
+          distance, includeKeys);
+}
+
+/**
+ * [_TimesMatcher]s are used to make assertions about the number of
+ * times a method was called.
+ */
+class _TimesMatcher extends BaseMatcher {
+  final int min, max;
+
+  const _TimesMatcher(this.min, [this.max = -1]);
+
+  bool matches(logList, MatchState matchState) => logList.length >= min &&
+      (max < 0 || logList.length <= max);
+
+  Description describe(Description description) {
+    description.add('to be called ');
+    if (max < 0) {
+      description.add('at least $min');
+    } else if (max == min) {
+      description.add('$max');
+    } else if (min == 0) {
+      description.add('at most $max');
+    } else {
+      description.add('between $min and $max');
+    }
+    return description.add(' times');
+  }
+
+  Description describeMismatch(logList, Description mismatchDescription,
+                               MatchState matchState, bool verbose) =>
+      mismatchDescription.add('was called ${logList.length} times');
+}
+
+/** [happenedExactly] matches an exact number of calls. */
+Matcher happenedExactly(count) {
+  return new _TimesMatcher(count, count);
+}
+
+/** [happenedAtLeast] matches a minimum number of calls. */
+Matcher happenedAtLeast(count) {
+  return new _TimesMatcher(count);
+}
+
+/** [happenedAtMost] matches a maximum number of calls. */
+Matcher happenedAtMost(count) {
+  return new _TimesMatcher(0, count);
+}
+
+/** [neverHappened] matches zero calls. */
+const Matcher neverHappened = const _TimesMatcher(0, 0);
+
+/** [happenedOnce] matches exactly one call. */
+const Matcher happenedOnce = const _TimesMatcher(1, 1);
+
+/** [happenedAtLeastOnce] matches one or more calls. */
+const Matcher happenedAtLeastOnce = const _TimesMatcher(1);
+
+/** [happenedAtMostOnce] matches zero or one call. */
+const Matcher happenedAtMostOnce = const _TimesMatcher(0, 1);
+
+/**
+ * [_ResultMatcher]s are used to make assertions about the results
+ * of method calls. These can be used as optional parameters to [getLogs].
+ */
+class _ResultMatcher extends BaseMatcher {
+  final Action action;
+  final Matcher value;
+
+  const _ResultMatcher(this.action, this.value);
+
+  bool matches(item, MatchState matchState) {
+    if (item is! LogEntry) {
+     return false;
+    }
+    // normalize the action; _PROXY is like _RETURN.
+    Action eaction = item.action;
+    if (eaction == Action.PROXY) {
+      eaction = Action.RETURN;
+    }
+    return (eaction == action && value.matches(item.value, matchState));
+  }
+
+  Description describe(Description description) {
+    description.add(' to ');
+    if (action == Action.RETURN || action == Action.PROXY)
+      description.add('return ');
+    else
+      description.add('throw ');
+    return description.addDescriptionOf(value);
+  }
+
+  Description describeMismatch(item, Description mismatchDescription,
+                               MatchState matchState, bool verbose) {
+    if (item.action == Action.RETURN || item.action == Action.PROXY) {
+      mismatchDescription.add('returned ');
+    } else {
+      mismatchDescription.add('threw ');
+    }
+    mismatchDescription.add(item.value);
+    return mismatchDescription;
+  }
+}
+
+/**
+ *[returning] matches log entries where the call to a method returned
+ * a value that matched [value].
+ */
+Matcher returning(value) =>
+    new _ResultMatcher(Action.RETURN, wrapMatcher(value));
+
+/**
+ *[throwing] matches log entrues where the call to a method threw
+ * a value that matched [value].
+ */
+Matcher throwing(value) =>
+    new _ResultMatcher(Action.THROW, wrapMatcher(value));
+
+/** Special values for use with [_ResultSetMatcher] [frequency]. */
+class _Frequency {
+  /** Every call/throw must match */
+  static const ALL = const _Frequency._('ALL');
+
+  /** At least one call/throw must match. */
+  static const SOME = const _Frequency._('SOME');
+
+  /** No calls/throws should match. */
+  static const NONE = const _Frequency._('NONE');
+
+  const _Frequency._(this.name);
+
+  final String name;
+}
+
+/**
+ * [_ResultSetMatcher]s are used to make assertions about the results
+ * of method calls. When filtering an execution log by calling
+ * [getLogs], a [LogEntrySet] of matching call logs is returned;
+ * [_ResultSetMatcher]s can then assert various things about this
+ * (sub)set of logs.
+ *
+ * We could make this class use _ResultMatcher but it doesn't buy that
+ * match and adds some perf hit, so there is some duplication here.
+ */
+class _ResultSetMatcher extends BaseMatcher {
+  final Action action;
+  final Matcher value;
+  final _Frequency frequency; // ALL, SOME, or NONE.
+
+  const _ResultSetMatcher(this.action, this.value, this.frequency);
+
+  bool matches(logList, MatchState matchState) {
+    for (LogEntry entry in logList) {
+      // normalize the action; PROXY is like RETURN.
+      Action eaction = entry.action;
+      if (eaction == Action.PROXY) {
+        eaction = Action.RETURN;
+      }
+      if (eaction == action && value.matches(entry.value, matchState)) {
+        if (frequency == _Frequency.NONE) {
+          matchState.state = {
+              'state' : matchState.state,
+              'entry' : entry
+          };
+          return false;
+        } else if (frequency == _Frequency.SOME) {
+          return true;
+        }
+      } else {
+        // Mismatch.
+        if (frequency == _Frequency.ALL) { // We need just one mismatch to fail.
+          matchState.state = {
+              'state' : matchState.state,
+              'entry' : entry
+          };
+          return false;
+        }
+      }
+    }
+    // If we get here, then if count is _ALL we got all matches and
+    // this is success; otherwise we got all mismatched which is
+    // success for count == _NONE and failure for count == _SOME.
+    return (frequency != _Frequency.SOME);
+  }
+
+  Description describe(Description description) {
+    description.add(' to ');
+    description.add(frequency == _Frequency.ALL ? 'alway ' :
+        (frequency == _Frequency.NONE ? 'never ' : 'sometimes '));
+    if (action == Action.RETURN || action == Action.PROXY)
+      description.add('return ');
+    else
+      description.add('throw ');
+    return description.addDescriptionOf(value);
+  }
+
+  Description describeMismatch(logList, Description mismatchDescription,
+                               MatchState matchState, bool verbose) {
+    if (frequency != _Frequency.SOME) {
+      LogEntry entry = matchState.state['entry'];
+      if (entry.action == Action.RETURN || entry.action == Action.PROXY) {
+        mismatchDescription.add('returned');
+      } else {
+        mismatchDescription.add('threw');
+      }
+      mismatchDescription.add(' value that ');
+      value.describeMismatch(entry.value, mismatchDescription,
+        matchState.state['state'], verbose);
+      mismatchDescription.add(' at least once');
+    } else {
+      mismatchDescription.add('never did');
+    }
+    return mismatchDescription;
+  }
+}
+
+/**
+ *[alwaysReturned] asserts that all matching calls to a method returned
+ * a value that matched [value].
+ */
+Matcher alwaysReturned(value) =>
+    new _ResultSetMatcher(Action.RETURN, wrapMatcher(value), _Frequency.ALL);
+
+/**
+ *[sometimeReturned] asserts that at least one matching call to a method
+ * returned a value that matched [value].
+ */
+Matcher sometimeReturned(value) =>
+    new _ResultSetMatcher(Action.RETURN, wrapMatcher(value), _Frequency.SOME);
+
+/**
+ *[neverReturned] asserts that no matching calls to a method returned
+ * a value that matched [value].
+ */
+Matcher neverReturned(value) =>
+    new _ResultSetMatcher(Action.RETURN, wrapMatcher(value), _Frequency.NONE);
+
+/**
+ *[alwaysThrew] asserts that all matching calls to a method threw
+ * a value that matched [value].
+ */
+Matcher alwaysThrew(value) =>
+    new _ResultSetMatcher(Action.THROW, wrapMatcher(value), _Frequency.ALL);
+
+/**
+ *[sometimeThrew] asserts that at least one matching call to a method threw
+ * a value that matched [value].
+ */
+Matcher sometimeThrew(value) =>
+  new _ResultSetMatcher(Action.THROW, wrapMatcher(value), _Frequency.SOME);
+
+/**
+ *[neverThrew] asserts that no matching call to a method threw
+ * a value that matched [value].
+ */
+Matcher neverThrew(value) =>
+  new _ResultSetMatcher(Action.THROW, wrapMatcher(value), _Frequency.NONE);
+
+/** The shared log used for named mocks. */
+LogEntryList sharedLog = null;
+
+/**
+ * [Mock] is the base class for all mocked objects, with
+ * support for basic mocking.
+ *
+ * To create a mock objects for some class T, create a new class using:
+ *
+ *     class MockT extends Mock implements T {};
+ *
+ * Then specify the [Behavior] of the Mock for different methods using
+ * [when] (to select the method and parameters) and then the [Action]s
+ * for the [Behavior] by calling [thenReturn], [alwaysReturn], [thenThrow],
+ * [alwaysThrow], [thenCall] or [alwaysCall].
+ *
+ * [thenReturn], [thenThrow] and [thenCall] are one-shot so you would
+ * typically call these more than once to specify a sequence of actions;
+ * this can be done with chained calls, e.g.:
+ *
+ *      m.when(callsTo('foo')).
+ *          thenReturn(0).thenReturn(1).thenReturn(2);
+ *
+ * [thenCall] and [alwaysCall] allow you to proxy mocked methods, chaining
+ * to some other implementation. This provides a way to implement 'spies'.
+ *
+ * You can disable logging for a particular [Behavior] easily:
+ *
+ *     m.when(callsTo('bar')).logging = false;
+ *
+ * You can then use the mock object. Once you are done, to verify the
+ * behavior, use [getLogs] to extract a relevant subset of method call
+ * logs and apply [Matchers] to these through calling [verify].
+ *
+ * A Mock can be given a name when constructed. In this case instead of
+ * keeping its own log, it uses a shared log. This can be useful to get an
+ * audit trail of interleaved behavior. It is the responsibility of the user
+ * to ensure that mock names, if used, are unique.
+ *
+ * Limitations:
+ * - only positional parameters are supported (up to 10);
+ * - to mock getters you will need to include parentheses in the call
+ *       (e.g. m.length() will work but not m.length).
+ *
+ * Here is a simple example:
+ *
+ *     class MockList extends Mock implements List {};
+ *
+ *     List m = new MockList();
+ *     m.when(callsTo('add', anything)).alwaysReturn(0);
+ *
+ *     m.add('foo');
+ *     m.add('bar');
+ *
+ *     getLogs(m, callsTo('add', anything)).verify(happenedExactly(2));
+ *     getLogs(m, callsTo('add', 'foo')).verify(happenedOnce);
+ *     getLogs(m, callsTo('add', 'isNull)).verify(neverHappened);
+ *
+ * Note that we don't need to provide argument matchers for all arguments,
+ * but we do need to provide arguments for all matchers. So this is allowed:
+ *
+ *     m.when(callsTo('add')).alwaysReturn(0);
+ *     m.add(1, 2);
+ *
+ * But this is not allowed and will throw an exception:
+ *
+ *     m.when(callsTo('add', anything, anything)).alwaysReturn(0);
+ *     m.add(1);
+ *
+ * Here is a way to implement a 'spy', which is where we log the call
+ * but then hand it off to some other function, which is the same
+ * method in a real instance of the class being mocked:
+ *
+ *     class Foo {
+ *       bar(a, b, c) => a + b + c;
+ *     }
+ *
+ *     class MockFoo extends Mock implements Foo {
+ *       Foo real;
+ *       MockFoo() {
+ *         real = new Foo();
+ *         this.when(callsTo('bar')).alwaysCall(real.bar);
+ *       }
+ *     }
+ *
+ */
+class Mock {
+  /** The mock name. Needed if the log is shared; optional otherwise. */
+  final String name;
+
+  /** The set of [Behavior]s supported. */
+  Map<String,Behavior> _behaviors;
+
+  /** The [log] of calls made. Only used if [name] is null. */
+  LogEntryList log;
+
+  /** How to handle unknown method calls - swallow or throw. */
+  final bool _throwIfNoBehavior;
+
+  /** Whether to create an audit log or not. */
+  bool _logging;
+
+  bool get logging => _logging;
+  set logging(bool value) {
+    if (value && log == null) {
+      log = new LogEntryList();
+    }
+    _logging = value;
+  }
+
+  /**
+   * Default constructor. Unknown method calls are allowed and logged,
+   * the mock has no name, and has its own log.
+   */
+  Mock() : _throwIfNoBehavior = false, log = null, name = null {
+    logging = true;
+    _behaviors = new Map<String,Behavior>();
+  }
+
+  /**
+   * This constructor makes a mock that has a [name] and possibly uses
+   * a shared [log]. If [throwIfNoBehavior] is true, any calls to methods
+   * that have no defined behaviors will throw an exception; otherwise they
+   * will be allowed and logged (but will not do anything).
+   * If [enableLogging] is false, no logging will be done initially (whether
+   * or not a [log] is supplied), but [logging] can be set to true later.
+   */
+  Mock.custom({this.name,
+               this.log,
+               throwIfNoBehavior: false,
+               enableLogging: true}) : _throwIfNoBehavior = throwIfNoBehavior {
+    if (log != null && name == null) {
+      throw new Exception("Mocks with shared logs must have a name.");
+    }
+    logging = enableLogging;
+    _behaviors = new Map<String,Behavior>();
+  }
+
+  /**
+   * [when] is used to create a new or extend an existing [Behavior].
+   * A [CallMatcher] [filter] must be supplied, and the [Behavior]s for
+   * that signature are returned (being created first if needed).
+   *
+   * Typical use case:
+   *
+   *     mock.when(callsTo(...)).alwaysReturn(...);
+   */
+  Behavior when(CallMatcher logFilter) {
+    String key = logFilter.toString();
+    if (!_behaviors.containsKey(key)) {
+      Behavior b = new Behavior(logFilter);
+      _behaviors[key] = b;
+      return b;
+    } else {
+      return _behaviors[key];
+    }
+  }
+
+  /**
+   * This is the handler for method calls. We loo through the list
+   * of [Behavior]s, and find the first match that still has return
+   * values available, and then do the action specified by that
+   * return value. If we find no [Behavior] to apply an exception is
+   * thrown.
+   */
+  noSuchMethod(String method, List args) {
+    if (method.startsWith('get:')) {
+      method = 'get ${method.substring(4)}';
+    }
+    bool matchedMethodName = false;
+    MatchState matchState = new MatchState();
+    for (String k in _behaviors.keys) {
+      Behavior b = _behaviors[k];
+      if (b.matcher.nameFilter.matches(method, matchState)) {
+        matchedMethodName = true;
+      }
+      if (b.matches(method, args)) {
+        List actions = b.actions;
+        if (actions == null || actions.length == 0) {
+          continue; // No return values left in this Behavior.
+        }
+        // Get the first response.
+        Responder response = actions[0];
+        // If it is exhausted, remove it from the list.
+        // Note that for endlessly repeating values, we started the count at
+        // 0, so we get a potentially useful value here, which is the
+        // (negation of) the number of times we returned the value.
+        if (--response.count == 0) {
+          actions.removeRange(0, 1);
+        }
+        // Do the response.
+        Action action = response.action;
+        var value = response.value;
+        if (action == Action.RETURN) {
+          if (_logging && b.logging) {
+            log.add(new LogEntry(name, method, args, action, value));
+          }
+          return value;
+        } else if (action == Action.THROW) {
+          if (_logging && b.logging) {
+            log.add(new LogEntry(name, method, args, action, value));
+          }
+          throw value;
+        } else if (action == Action.PROXY) {
+          var rtn;
+          switch (args.length) {
+            case 0:
+              rtn = value();
+              break;
+            case 1:
+              rtn = value(args[0]);
+              break;
+            case 2:
+              rtn = value(args[0], args[1]);
+              break;
+            case 3:
+              rtn = value(args[0], args[1], args[2]);
+              break;
+            case 4:
+              rtn = value(args[0], args[1], args[2], args[3]);
+              break;
+            case 5:
+              rtn = value(args[0], args[1], args[2], args[3], args[4]);
+              break;
+            case 6:
+              rtn = value(args[0], args[1], args[2], args[3],
+                  args[4], args[5]);
+              break;
+            case 7:
+              rtn = value(args[0], args[1], args[2], args[3],
+                  args[4], args[5], args[6]);
+              break;
+            case 8:
+              rtn = value(args[0], args[1], args[2], args[3],
+                  args[4], args[5], args[6], args[7]);
+              break;
+            case 9:
+              rtn = value(args[0], args[1], args[2], args[3],
+                  args[4], args[5], args[6], args[7], args[8]);
+              break;
+            case 9:
+              rtn = value(args[0], args[1], args[2], args[3],
+                  args[4], args[5], args[6], args[7], args[8], args[9]);
+              break;
+            default:
+              throw new Exception(
+                  "Cannot proxy calls with more than 10 parameters.");
+          }
+          if (_logging && b.logging) {
+            log.add(new LogEntry(name, method, args, action, rtn));
+          }
+          return rtn;
+        }
+      }
+    }
+    if (matchedMethodName) {
+      // User did specify behavior for this method, but all the
+      // actions are exhausted. This is considered an error.
+      throw new Exception('No more actions for method '
+          '${_qualifiedName(name, method)}.');
+    } else if (_throwIfNoBehavior) {
+      throw new Exception('No behavior specified for method '
+          '${_qualifiedName(name, method)}.');
+    }
+    // Otherwise user hasn't specified behavior for this method; we don't throw
+    // so we can underspecify.
+    if (_logging) {
+      log.add(new LogEntry(name, method, args, Action.IGNORE));
+    }
+  }
+
+  /** [verifyZeroInteractions] returns true if no calls were made */
+  bool verifyZeroInteractions() {
+    if (log == null) {
+      // This means we created the mock with logging off and have never turned
+      // it on, so it doesn't make sense to verify behavior on such a mock.
+      throw new
+          Exception("Can't verify behavior when logging was never enabled.");
+    }
+    return log.logs.length == 0;
+  }
+
+  /**
+   * [getLogs] extracts all calls from the call log that match the
+   * [logFilter], and returns the matching list of [LogEntry]s. If
+   * [destructive] is false (the default) the matching calls are left
+   * in the log, else they are removed. Removal allows us to verify a
+   * set of interactions and then verify that there are no other
+   * interactions left. [actionMatcher] can be used to further
+   * restrict the returned logs based on the action the mock performed.
+   * [logFilter] can be a [CallMatcher] or a predicate function that
+   * takes a [LogEntry] and returns a bool.
+   *
+   * Typical usage:
+   *
+   *     getLogs(callsTo(...)).verify(...);
+   */
+  LogEntryList getLogs([CallMatcher logFilter,
+                        Matcher actionMatcher,
+                        bool destructive = false]) {
+    if (log == null) {
+      // This means we created the mock with logging off and have never turned
+      // it on, so it doesn't make sense to get logs from such a mock.
+      throw new
+          Exception("Can't retrieve logs when logging was never enabled.");
+    } else {
+      return log.getMatches(name, logFilter, actionMatcher, destructive);
+    }
+  }
+
+  /**
+   * Useful shorthand method that creates a [CallMatcher] from its arguments
+   * and then calls [getLogs].
+   */
+  LogEntryList calls(method,
+                      [arg0 = _noArg,
+                       arg1 = _noArg,
+                       arg2 = _noArg,
+                       arg3 = _noArg,
+                       arg4 = _noArg,
+                       arg5 = _noArg,
+                       arg6 = _noArg,
+                       arg7 = _noArg,
+                       arg8 = _noArg,
+                       arg9 = _noArg]) =>
+      getLogs(callsTo(method, arg0, arg1, arg2, arg3, arg4,
+          arg5, arg6, arg7, arg8, arg9));
+
+  /** Clear the behaviors for the Mock. */
+  void resetBehavior() => _behaviors.clear();
+
+  /** Clear the logs for the Mock. */
+  void clearLogs() {
+    if (log != null) {
+      if (name == null) { // This log is not shared.
+        log.logs.clear();
+      } else { // This log may be shared.
+        log.logs = log.logs.filter((e) => e.mockName != name);
+      }
+    }
+  }
+
+  /** Clear both logs and behavior. */
+  void reset() {
+    resetBehavior();
+    clearLogs();
+  }
+}