feat(zone.js): include jasmine describe block name when raising une…

…xpected task error

As mentioned in the previous commit that ensured that the Zone name is
included in errors raised by the `SyncTestZoneSpec`, we can now include
the Jasmine describe block descriptions in such errors.

Errors can often happen when users accidentally try to set up Angular
tests without an `it` block. Resulting in errors where it's not clear
at all which describe block (of potentially a large repository) is
involved:

```
 An error was thrown in afterAll
  error properties: Object({ originalStack: 'Error: Cannot call XX from within a sync test.
      at new ZoneAwareError (packages/zone.js/test/browser_test_rollup.umd.js:98:37)
      at e.onScheduleTask (packages/zone.js/bundles/zone-testing-bundle.umd.min.js:158:196)
      at e.scheduleTask (packages/zone.js/bundles/zone-testing-bundle.umd.min.js:14:7529)
      at t.scheduleTask (packages/zone.js/bundles/zone-testing-bundle.umd.min.js:14:3539)
      at t.scheduleMicroTask (packages/zone.js/bundles/zone-testing-bundle.umd.min.js:14:3791)
      at r.execute (packages/zone.js/bundles/zone-testing-bundle.umd.min.js:166:4372)
      at queueRunnerFa ...
      at <Jasmine>
```

We now include the describe block description in the error, so that it
is easier to figure out the location of the culprit code.

packages/zone.js/lib/jasmine/jasmine.ts

@@ -38,10 +38,6 @@ Zone.__load_patch('jasmine', (global: any, Zone: ZoneType, api: _ZonePrivate) =>
   if (!ProxyZoneSpec) throw new Error('Missing: ProxyZoneSpec');
 
   const ambientZone = Zone.current;
-  // Create a synchronous-only zone in which to run `describe` blocks in order to raise an
-  // error if any asynchronous operations are attempted inside of a `describe` but outside of
-  // a `beforeEach` or `it`.
-  const syncZone = ambientZone.fork(new SyncTestZoneSpec('jasmine.describe'));
 
   const symbol = Zone.__symbol__;
 
@@ -100,7 +96,8 @@ Zone.__load_patch('jasmine', (global: any, Zone: ZoneType, api: _ZonePrivate) =>
   ['describe', 'xdescribe', 'fdescribe'].forEach(methodName => {
     let originalJasmineFn: Function = jasmineEnv[methodName];
     jasmineEnv[methodName] = function(description: string, specDefinitions: Function) {
-      return originalJasmineFn.call(this, description, wrapDescribeInZone(specDefinitions));
+      return originalJasmineFn.call(
+          this, description, wrapDescribeInZone(description, specDefinitions));
     };
   });
   ['it', 'xit', 'fit'].forEach(methodName => {
@@ -198,8 +195,11 @@ Zone.__load_patch('jasmine', (global: any, Zone: ZoneType, api: _ZonePrivate) =>
    * Gets a function wrapping the body of a Jasmine `describe` block to execute in a
    * synchronous-only zone.
    */
-  function wrapDescribeInZone(describeBody: Function): Function {
+  function wrapDescribeInZone(description: string, describeBody: Function): Function {
     return function(this: unknown) {
+      // Create a synchronous-only zone in which to run `describe` blocks in order to raise an
+      // error if any asynchronous operations are attempted inside of a `describe`.
+      const syncZone = ambientZone.fork(new SyncTestZoneSpec(`jasmine.describe#${description}`));
       return syncZone.run(describeBody, this, (arguments as any) as any[]);
     };
   }
@@ -332,6 +332,10 @@ Zone.__load_patch('jasmine', (global: any, Zone: ZoneType, api: _ZonePrivate) =>
 
       if (!isChildOfAmbientZone) throw new Error('Unexpected Zone: ' + Zone.current.name);
 
+
+      Error.stackTraceLimit = Infinity;
+      let context = new Error().stack;
+
       // This is the zone which will be used for running individual tests.
       // It will be a proxy zone, so that the tests function can retroactively install
       // different zones.

packages/zone.js/test/jasmine-patch.spec.ts

@@ -38,7 +38,7 @@ ifEnvSupports(supportJasmineSpec, () => {
 
     it('should throw on async in describe', () => {
       expect(throwOnAsync).toBe(true);
-      expect(syncZone.name).toEqual('syncTestZone for jasmine.describe');
+      expect(syncZone.name).toEqual('syncTestZone for jasmine.describe#jasmine');
       itZone = Zone.current;
     });