add test replicating apache#29365 bug

sdks/python/apache_beam/runners/dask/dask_runner_test.py

@@ -73,6 +73,11 @@ def test_create(self):
       pcoll = p | beam.Create([1])
       assert_that(pcoll, equal_to([1]))
 
+  def test_create_multiple(self):
+    with self.pipeline as p:
+      pcoll = p | beam.Create([1, 2, 3, 4])
+      assert_that(pcoll, equal_to([1, 2, 3, 4]))
+
   def test_create_and_map(self):
     def double(x):
       return x * 2
@@ -89,6 +94,14 @@ def double(x):
       pcoll = p | beam.Create([1]) | beam.Map(double) | beam.GroupByKey()
       assert_that(pcoll, equal_to([(2, [1])]))
 
+  def test_groupby_string_keys(self):
+    with self.pipeline as p:
+      pcoll = (
+          p
+          | beam.Create([('a', 1), ('a', 2), ('b', 3), ('b', 4)])
+          | beam.GroupByKey())
+      assert_that(pcoll, equal_to([('a', [1, 2]), ('b', [3, 4])]))
+
 
 if __name__ == '__main__':
   unittest.main()