Performing actions that trigger computations

Spark has a lot more actions that issue DAG, and we should be aware of all of them because they are very important. In this section, we'll understand what can be an action in Spark, do a walk-through of actions, and test those actions if they behave as expected.

The first action we covered is collect. We also covered two actions besides that—we covered both reduce and reduceByKey in the previous section. Both methods are actions because they return a single result.

First, we will create the input of our transactions and then apply some transformations just for testing purposes. We will take only the user that contains A, using keyBy_.userId, and then take only the amount of the required transaction, as shown in the following example:

test("should trigger computations using actions") {
     //given
     val input...