Don't crash 'pub get' if a dev dependency is broken.

sdk/lib/_internal/pub_generated/test/pubspec_test.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 pubspec_test;
 
 import 'dart:async';
 
 import 'package:pub_semver/pub_semver.dart';
 import 'package:unittest/unittest.dart';
 
 import '../lib/src/package.dart';
 import '../lib/src/pubspec.dart';
 import '../lib/src/source.dart';
+import '../lib/src/source/path.dart';
 import '../lib/src/source_registry.dart';
 import 'test_pub.dart';
 
 class MockSource extends Source {
   final String name = "mock";
 
   Future<Pubspec> doDescribe(PackageId id) =>
       throw new UnsupportedError("Cannot describe mock packages.");
 
   Future get(PackageId id, String symlink) =>
@@ skipping 12 matching lines @@
       description1 == description2;
 
   String packageName(description) => 'foo';
 }
 
 main() {
   initConfig();
   group('parse()', () {
     var sources = new SourceRegistry();
     sources.register(new MockSource());
+    sources.register(new PathSource());
 
     var throwsPubspecException =
         throwsA(new isInstanceOf<PubspecException>('PubspecException'));
 
     expectPubspecException(String contents, fn(Pubspec pubspec),
         [String expectedContains]) {
       var expectation = throwsPubspecException;
       if (expectedContains != null) {
         expectation = throwsA(
             allOf(
@@ skipping 103 matching lines @@
   foo:
     unknown: blah
 ''', sources);
 
       var foo = pubspec.dependencies[0];
       expect(foo.name, equals('foo'));
       expect(foo.source, equals('unknown'));
     });
 
     test("throws if a package is in dependencies and dev_dependencies", () {
-      var contents = '''
+      expectPubspecException('''
 dependencies:
   foo:
     mock: ok
 dev_dependencies:
   foo:
     mock: ok
-''';
-      expectPubspecException(contents, (pubspec) => pubspec.dependencies);
-      expectPubspecException(contents, (pubspec) => pubspec.devDependencies);
+''', (pubspec) {
+        // This check only triggers if both [dependencies] and [devDependencies]
+        // are accessed.
+        pubspec.dependencies;
+        pubspec.devDependencies;
+      });
     });
 
     test("throws if it dependes on itself", () {
       expectPubspecException('''
 name: myapp
 dependencies:
   myapp:
     mock: ok
 ''', (pubspec) => pubspec.dependencies);
     });
@@ skipping 206 matching lines @@
       var pubspec = new Pubspec.parse('''
 # No external dependencies yet
 # Including for completeness
 # ...and hoping the spec expands to include details about author, version, etc
 # See http://www.dartlang.org/docs/pub-package-manager/ for details
 ''', sources);
       expect(pubspec.version, equals(Version.none));
       expect(pubspec.dependencies, isEmpty);
     });
 
+    test("throws a useful error for unresolvable path dependencies", () {
+      expectPubspecException('''
+name: pkg
+dependencies:
+  from_path: {path: non_local_path}
+''',
+          (pubspec) => pubspec.dependencies,
+          '"non_local_path" is a relative path, but this isn\'t a local ' 'pubspec.');
+    });
+
     group("environment", () {
       test("defaults to any SDK constraint if environment is omitted", () {
         var pubspec = new Pubspec.parse('', sources);
         expect(pubspec.environment.sdkVersion, equals(VersionConstraint.any));
       });
 
       test("allows an empty environment map", () {
         var pubspec = new Pubspec.parse('''
 environment:
 ''', sources);
@@ skipping 118 matching lines @@
       test("uses the key if the value is null", () {
         var pubspec = new Pubspec.parse('''
 executables:
   command:
 ''', sources);
         expect(pubspec.executables['command'], equals('command'));
       });
     });
   });
 }