Refactor service tests in preparation of running on sky_shell

runtime/observatory/tests/service/issue_25465_test.dart

 // Copyright (c) 2015, 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.
 // VMOptions=--error_on_bad_type --error_on_bad_override
 
 import 'package:observatory/service_io.dart';
 import 'package:unittest/unittest.dart';
 import 'test_helper.dart';
+import 'service_test_common.dart';
 import 'dart:async';
 
+const int LINE_A = 16;
+const int LINE_B = 17;
+
 testMain() {
-  var foo;      // line 11
-  foo = 42;     // line 12
+  var foo;      // line A
+  foo = 42;     // line B
   print(foo);
 }
 
 var tests = [
   hasPausedAtStart,
 
   // Add breakpoints at line 11 and line 12.
   (Isolate isolate) async {
     var rootLib = isolate.rootLibrary;
     await rootLib.load();
     var script = rootLib.scripts[0];
 
-    var bpt1 = await isolate.addBreakpoint(script, 11);
-    var bpt2 = await isolate.addBreakpoint(script, 12);
-    expect(await bpt1.location.getLine(), equals(11));
-    expect(await bpt2.location.getLine(), equals(12));
+    var bpt1 = await isolate.addBreakpoint(script, LINE_A);
+    var bpt2 = await isolate.addBreakpoint(script, LINE_B);
+    expect(await bpt1.location.getLine(), equals(LINE_A));
+    expect(await bpt2.location.getLine(), equals(LINE_B));
 
     var stream = await isolate.vm.getEventStream(VM.kDebugStream);
     Completer completer = new Completer();
     var subscription;
     var breakCount = 0;
     subscription = stream.listen((ServiceEvent event) async {
       if (event.kind == ServiceEvent.kPauseBreakpoint) {
         breakCount++;
         print('break count is $breakCount');
         if (breakCount == 1) {
           // We are stopped at breakpoint 1.
           expect(event.breakpoint.number, equals(bpt1.number));
 
           // Remove both breakpoints
           var result = await isolate.removeBreakpoint(bpt1);
           expect(result.type, equals("Success"));
 
           result = await isolate.removeBreakpoint(bpt2);
           expect(result.type, equals("Success"));
 
           isolate.stepOver();
         } else {
           // No breakpoint.
           expect(event.breakpoint, isNull);
 
-          // We expect the next step to take us to line 12.
+          // We expect the next step to take us to line B.
           var stack = await isolate.getStack();
-          expect(await stack['frames'][0].location.getLine(), equals(12));
+          expect(await stack['frames'][0].location.getLine(), equals(LINE_B));
 
           subscription.cancel();
           completer.complete(null);
         }
       }
     });
     isolate.resume();
     await completer.future;
   },
 ];
 
 main(args) => runIsolateTests(args, tests,
                               testeeConcurrent: testMain,
                               pause_on_start: true);