Fix the queue tree from resolving in between the testcase.

lib/core/asynctree.js

@@ -212,6 +212,10 @@ class AsyncTree extends EventEmitter{
   }
 
   async done(err = null) {
+    if (this.currentResult instanceof Promise && !this.currentResult.settled) {
+      return err;
+    }
+
     this.emit('asynctree:finished', this);
     this.empty();
     this.createRootNode();

lib/core/queue.js

@@ -145,7 +145,9 @@ class CommandQueue extends EventEmitter {
     return Promise.resolve();
   }
 
-  run() {
+  run(result) {
+    this.tree.currentResult = result;
+
     if (this.tree.started) {
       return this;
     }

lib/testsuite/runnable.js

@@ -103,8 +103,8 @@ class Runnable {
   }
 
   setDoneCallback(cb) {
-    let originalResolve = this.deffered.resolveFn;
-    let originalReject = this.deffered.rejectFn;
+    const originalResolve = this.deffered.resolveFn;
+    const originalReject = this.deffered.rejectFn;
     this.deffered.resolveFn = function() {};
     this.deffered.rejectFn = function() {};
 
@@ -134,13 +134,22 @@ class Runnable {
       const deferredFn = () => {
         result
           .then(res_ => {
+            result.settled = true;
             if (this.queueInProgress()) {
+              // After resolution of testcase (`result` here), if there are some more
+              // commands left to be run in the queue, the queue will automatically resolve
+              // after those commands are finished running. But, if at this time, the queue
+              // is already done running and was not resolved earlier because the testcase
+              // was not yet resolved, this gives another chance for the queue to be resolved.
+              this.queue.scheduleTraverse();
+
               return;
             }
 
             this.deffered.resolveFn(res_);
           })
           .catch(err => {
+            result.settled = true;
             this.deffered.rejectFn(err);
           });
       };
@@ -152,14 +161,15 @@ class Runnable {
         // without .catch() here, we can get an unhandledRejection
         result
           .catch(err => {
+            result.settled = true;
             this.deffered.rejectFn(err);
           });
       } else {
         deferredFn();
       }
     }
 
-    this.queue.run().then(err => {
+    this.queue.run(result).then(err => {
       if (err) {
         return this.deffered.rejectFn(err);
       }