Create binstubs for executables when activating a package.

sdk/lib/_internal/pub_generated/test/pubspec_test.dart

Index: sdk/lib/_internal/pub_generated/test/pubspec_test.dart
diff --git a/sdk/lib/_internal/pub_generated/test/pubspec_test.dart b/sdk/lib/_internal/pub_generated/test/pubspec_test.dart
index 1f308d046ceed93093463799151387cc97c4dd62..d1273024a413d60482855b29e07aea114403ab33 100644
--- a/sdk/lib/_internal/pub_generated/test/pubspec_test.dart
+++ b/sdk/lib/_internal/pub_generated/test/pubspec_test.dart
@@ -386,5 +386,43 @@ publish_to: none
             (pubspec) => pubspec.publishTo);
       });
     });
+    group("executables", () {
+      test("defaults to an empty map if omitted", () {
+        var pubspec = new Pubspec.parse('', sources);
+        expect(pubspec.executables, isEmpty);
+      });
+      test("throws if not a map", () {
+        expectPubspecException(
+            'executables: not map',
+            (pubspec) => pubspec.executables);
+      });
+      test("throws if key is not a string", () {
+        expectPubspecException(
+            'executables: {123: value}',
+            (pubspec) => pubspec.executables);
+      });
+      test("throws if a key isn't a simple name", () {
+        expectPubspecException(
+            'executables: {funny/name: ok}',
+            (pubspec) => pubspec.executables);
+      });
+      test("throws if a value is not a string", () {
+        expectPubspecException(
+            'executables: {command: 123}',
+            (pubspec) => pubspec.executables);
+      });
+      test("throws if a value isn't a simple name", () {
+        expectPubspecException(
+            'executables: {command: funny_name/part}',
+            (pubspec) => pubspec.executables);
+      });
+      test("allows a null value", () {
+        var pubspec = new Pubspec.parse('''
+executables:
+  command:
+''', sources);
+        expect(pubspec.executables['command'], isNull);
+      });
+    });
   });
 }