Fix dart2js/source_map_pub_build_validity_test.

This relied on "pub build" implicitly running "pub get", which it no
longer does.

Fixes #24102

[email protected]

Review URL: https://codereview.chromium.org//1295653005 .

Author: whesse

tests/compiler/dart2js/source_map_pub_build_validity_test.dart

@@ -10,25 +10,37 @@ import 'package:expect/expect.dart';
 import 'source_map_validator_helper.dart';
 
 void main() {
-  asyncTest(() => createTempDir().then((Directory tmpDir) {
-    Directory sunflowerDir = new Directory.fromUri(
-        Platform.script.resolve('../../../third_party/sunflower'));
+  asyncTest(() async {
+    Directory tmpDir = createTempDir();
+    try {
+      Directory sunflowerDir = new Directory.fromUri(
+          Platform.script.resolve('../../../third_party/sunflower'));
 
-    print("Copying '${sunflowerDir.path}' to '${tmpDir.path}'.");
-    copyDirectory(sunflowerDir, tmpDir);
-    String ext = Platform.isWindows ? '.bat' : '';
-    String command = path.normalize(path.join(path.fromUri(Platform.script),
-                                              '../../../../sdk/bin/pub${ext}'));
-    String file = path.join(tmpDir.path, 'build/web/sunflower.dart.js');
-    print("Running '$command build --mode=debug' from '${tmpDir}'.");
-    return Process.run(command, ['build','--mode=debug'],
-        workingDirectory: tmpDir.path).then((ProcessResult processResult) {
-      print(processResult.stdout);
-      print(processResult.stderr);
-      Expect.equals(0, processResult.exitCode, 'Unexpected exitCode from pub');
+      print("Copying '${sunflowerDir.path}' to '${tmpDir.path}'.");
+      copyDirectory(sunflowerDir, tmpDir);
+      String ext = Platform.isWindows ? '.bat' : '';
+      String command = path.normalize(path.join(
+          path.fromUri(Platform.script),
+          '../../../../sdk/bin/pub${ext}'));
+      String file = path.join(tmpDir.path, 'build/web/sunflower.dart.js');
+
+      print("Running '$command get' from '${tmpDir}'.");
+      ProcessResult getResult = await Process.run(
+          command, ['get'], workingDirectory: tmpDir.path);
+      print(getResult.stdout);
+      print(getResult.stderr);
+      Expect.equals(0, getResult.exitCode, 'Unexpected exitCode from pub get');
+
+      print("Running '$command build --mode=debug' from '${tmpDir}'.");
+      ProcessResult buildResult = await Process.run(
+          command, ['build','--mode=debug'], workingDirectory: tmpDir.path);
+      print(buildResult.stdout);
+      print(buildResult.stderr);
+      Expect.equals(0, buildResult.exitCode, 'Unexpected exitCode from pub');
       validateSourceMap(new Uri.file(file, windows: Platform.isWindows));
       print("Deleting '${tmpDir.path}'.");
+    } finally {
       tmpDir.deleteSync(recursive: true);
-    });
+    }
   }));
 }