unittest step2: bye bye to multiple entrypoints for unittest

lib/unittest/expectation.dart

+// Copyright (c) 2011, 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 file is sourced by unittest.dart. It defines [Expectation]. */
+
+/**
+ * Wraps an value and provides methods that can be used to verify that the value
+ * matches a given expectation.
+ */
+class Expectation {
+  final _value;
+
+  Expectation(this._value);
+
+  /** Asserts that the value is equivalent to [expected]. */
+  void equals(expected) {
+    // Use the type-specialized versions when appropriate to give better
+    // error messages.
+    if (_value is String && expected is String) {
+      Expect.stringEquals(expected, _value);
+    } else if (_value is Map && expected is Map) {
+      Expect.mapEquals(expected, _value);
+    } else if (_value is Set && expected is Set) {
+      Expect.setEquals(expected, _value);
+    } else {
+      Expect.equals(expected, _value);
+    }
+  }
+
+  /**
+   * Asserts that the difference between [expected] and the value is within
+   * [tolerance]. If no tolerance is given, it is assumed to be the value 4
+   * significant digits smaller than the expected value.
+   */
+  void approxEquals(num expected,
+      [num tolerance = null, String reason = null]) {
+    Expect.approxEquals(expected, _value, tolerance: tolerance, reason: reason);
+  }
+
+  /** Asserts that the value is [null]. */
+  void isNull() {
+    Expect.equals(null, _value);
+  }
+
+  /** Asserts that the value is not [null]. */
+  void isNotNull() {
+    Expect.notEquals(null, _value);
+  }
+
+  /** Asserts that the value is [true]. */
+  void isTrue() {
+    Expect.equals(true, _value);
+  }
+
+  /** Asserts that the value is [false]. */
+  void isFalse() {
+    Expect.equals(false, _value);
+  }
+
+  /** Asserts that the value has the same elements as [expected]. */
+  void equalsCollection(Collection expected) {
+    Expect.listEquals(expected, _value);
+  }
+
+  /**
+   * Checks that every element of [expected] is also in [actual], and that
+   * every element of [actual] is also in [expected].
+   */
+  void equalsSet(Iterable expected) {
+    Expect.setEquals(expected, _value);
+  }
+}