diff --git a/tests/README b/tests/README
new file mode 100644
index 00000000000..a9e3bb62beb
--- /dev/null
+++ b/tests/README
@@ -0,0 +1,43 @@
+Run Existing Tests
+==================
+
+See the output of
+
+  ../tools/test.py --help
+
+for how to run tests.
+
+See also
+
+  https://code.google.com/p/dart/wiki/Building#Testing
+
+for detailed examples.
+
+Create New Tests
+================
+
+See comments above
+
+  factory StandardTestSuite.forDirectory
+
+in
+
+  ../tools/testing/dart/test_suite.dart
+
+for the default test directory layout. By default test-file names must
+end in "_test.dart", but some test suites, such as ./co19, subclass
+StandardTestSuite and override this default.
+
+See comments at the beginning of
+
+  ../tools/testing/dart/multitest.dart
+
+for how to create tests that pass by failing with a known error. For
+example,
+
+  ...
+  int x = "not an int"; /// 01: static type warning
+  ...
+
+as part of a test will only pass the "--compiler dartanalyzer" test if
+the assignment generates a static type warning.
diff --git a/tests/language/issue18628_1_test.dart b/tests/language/issue18628_1_test.dart
new file mode 100644
index 00000000000..9481efde144
--- /dev/null
+++ b/tests/language/issue18628_1_test.dart
@@ -0,0 +1,20 @@
+// Copyright (c) 2014, 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 test checks for a regression found in Dart Editor: the
+// analyzer was treating [Type] as more specific than any type
+// variable (generic parameter).
+//
+// https://code.google.com/p/dart/issues/detail?id=18628
+
+class C<T> {
+  // This line is supposed to cause the warning; the other commented
+  // line just doesn't make sense without this line.
+  T t = int; /// 01: static type warning
+}
+
+main() {
+  C<Type> c = new C<Type>();
+  print(c.t); /// 01: static type warning
+}
diff --git a/tests/language/issue18628_2_test.dart b/tests/language/issue18628_2_test.dart
new file mode 100644
index 00000000000..a6e1cfd73e4
--- /dev/null
+++ b/tests/language/issue18628_2_test.dart
@@ -0,0 +1,20 @@
+// Copyright (c) 2014, 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 test checks for a regression found in Dart Editor: the
+// analyzer was treating [Type] as more specific than any type
+// variable (generic parameter).
+//
+// https://code.google.com/p/dart/issues/detail?id=18628
+
+class X<T extends Type> {}
+
+// This line is supposed to cause the warning; the other lines are
+// marked because they don't make sense when [Y] is not defined.
+class Y<U> extends X<U> {} /// 01: static type warning
+
+main() {
+  X<Type> x = new X<Type>(); /// 01: static type warning
+  Y<Type> y = new Y<Type>(); /// 01: static type warning
+}
diff --git a/tools/test.dart b/tools/test.dart
index 89b9d728d07..880dd007b70 100755
--- a/tools/test.dart
+++ b/tools/test.dart
@@ -18,8 +18,12 @@
  * and passses along all command line arguments to this script.)
  *
  * The command line args of this script are documented in
- * "tools/testing/test_options.dart".
+ * "tools/testing/dart/test_options.dart"; they are printed
+ * when this script is run with "--help".
  *
+ * The default test directory layout is documented in
+ * "tools/testing/dart/test_suite.dart", above
+ * "factory StandardTestSuite.forDirectory".
  */
 
 library test;
diff --git a/tools/testing/dart/test_options.dart b/tools/testing/dart/test_options.dart
index f5259d7e963..ad4cccf1a47 100644
--- a/tools/testing/dart/test_options.dart
+++ b/tools/testing/dart/test_options.dart
@@ -823,7 +823,13 @@ Note: currently only implemented for dart2js.''',
    * Print out usage information.
    */
   void _printHelp() {
-    print('usage: dart test.dart [options]\n');
+    print('usage: dart test.dart [options] [selector]');
+    print('');
+    print('The optional selector limits the tests that will be run.');
+    print('For example, the selector "language/issue", or equivalently');
+    print('"language/*issue*", limits to test files matching the regexp');
+    print('".*issue.*\\.dart" in the "tests/language" directory.');
+    print('');
     print('Options:\n');
     for (var option in _options) {
       print('${option.name}: ${option.description}.');