test_runner: fix concurrent describe queuing

lib/internal/test_runner/test.js

@@ -561,25 +561,22 @@ class Suite extends Test {
 
     try {
       const context = { signal: this.signal };
-      this.buildSuite = this.runInAsyncScope(this.fn, context, [context]);
+      this.buildSuite = PromisePrototypeThen(
+        PromiseResolve(this.runInAsyncScope(this.fn, context, [context])),
+        undefined,
+        (err) => {
+          this.fail(new ERR_TEST_FAILURE(err, kTestCodeFailure));
+        });
     } catch (err) {
       this.fail(new ERR_TEST_FAILURE(err, kTestCodeFailure));
     }
     this.fn = () => {};
     this.buildPhaseFinished = true;
   }
 
-  start() {
-    return this.run();
-  }
-
   async run() {
-    try {
-      await this.buildSuite;
-    } catch (err) {
-      this.fail(new ERR_TEST_FAILURE(err, kTestCodeFailure));
-    }
     this.parent.activeSubtests++;
+    await this.buildSuite;
     this.startTime = hrtime();
 
     if (this[kShouldAbort]()) {

test/message/test_runner_describe_it.js

@@ -149,17 +149,6 @@ describe('level 0a', { concurrency: 4 }, () => {
   return p0a;
 });
 
-describe('top level', { concurrency: 2 }, () => {
-  it('+long running', async () => {
-    return new Promise((resolve, reject) => {
-      setTimeout(resolve, 3000).unref();
-    });
-  });
-
-  describe('+short running', async () => {
-    it('++short running', async () => {});
-  });
-});
 
 describe('invalid subtest - pass but subtest fails', () => {
   setImmediate(() => {
@@ -339,3 +328,47 @@ describe('timeouts', () => {
     setTimeout(done, 10);
   });
 });
+
+describe('successful thenable', () => {
+  it('successful thenable', () => {
+    let thenCalled = false;
+    return {
+      get then() {
+        if (thenCalled) throw new Error();
+        thenCalled = true;
+        return (successHandler) => successHandler();
+      },
+    };
+  });
+
+  it('rejected thenable', () => {
+    let thenCalled = false;
+    return {
+      get then() {
+        if (thenCalled) throw new Error();
+        thenCalled = true;
+        return (_, errorHandler) => errorHandler(new Error('custom error'));
+      },
+    };
+  });
+
+  let thenCalled = false;
+  return {
+    get then() {
+      if (thenCalled) throw new Error();
+      thenCalled = true;
+      return (successHandler) => successHandler();
+    },
+  };
+});
+
+describe('rejected thenable', () => {
+  let thenCalled = false;
+  return {
+    get then() {
+      if (thenCalled) throw new Error();
+      thenCalled = true;
+      return (_, errorHandler) => errorHandler(new Error('custom error'));
+    },
+  };
+});