Debugging message-based stubs

Use the Message Differences window or options available within the stub console display to debug message-based stubs.

Message-based stubs include an Events page that lists model messages that the stub attempts to match to incoming messages. Each of these model messages is considered a case, such as you would find in a switch statement in Java™. A Guard field offers the option to mark a model message as containing an Expression, or as No Match, which means that the message is to be used as a default if no other match is found. These messages are read in order, and the No Match option is available for the last message in the list only.

When you run a test against a stub, an entry is displayed on the stub console when a match is found. You can right click the entry for a list of options.

If you click Show Differences, the Message Differences window is displayed. See The Message Differences window for stubs in this topic. For the other options, see Console options in this topic.

If no match is found and you have a default case (a message with a No Match guard), an entry is displayed for the default case on the stub console. You can right click the entry for a list of options, as shown in the following illustration.

menu options include Enhance stub to support this request.

If you click Show Message, the Message Differences window is displayed. See The Message Differences window for stubs in this topic. For the other options, see Console options in this topic.

The Message Differences window for stubs

Use the Message Differences window to debug any message-based stubs that generate error messages on the Test Lab perspective Console window. Debug the stub to determine why no events were matched.

The Message Differences window provides the following benefits:
  • You do not have to move from the Test Lab perspective to the Test Factory perspective and analyze each expected message to determine why it did not match any of the events.
  • You have access to the received messages for side-by-side comparison with all expected messages from the events associated with the relevant operation in the currently selected stub.
Note:
This topic discusses only features of the Message Differences window that are relevant to stubs. For general information about using the Message Differences window, refer to API Tester Reference.
Note:
The Message Differences window cannot be used to debug a database stub created by Test Integrations and APIs.
  1. To debug a message-based stub that is taking the default case when it should match a particular event, click the default case output in the stub console, or the failed validation output in the console window for the Test Lab perspective.
    The Message Differences window is displayed.
    Note:
    You can use all IBM® DevOps Test Integrations and APIs (Test Integrations and APIs) perspectives while the Message Differences window is displayed. However, if you use the Stub Editor (or the Test Editor) to modify a stub (or a test) while also using the Message Differences window to modify the same resource, there will be two sets of pending changes to that resource. Therefore, when you attempt to close the Message Differences window, Test Integrations and APIs will prompt you to select the set of changes you want to keep.

    The Message Differences window collects all of the events associated with the relevant operation in the stub into one location. The events are displayed on the left side of the window and the message received is displayed on the right side of the window.

  2. Click the navigation buttons under Expected Message on the upper-left side of the window to move up and down through the events.
  3. Analyze any errors on the left side of the Message Differences window.
  4. Use the buttons under Repair and Action on the upper-right side of the Message Differences window to perform any of the following actions:
    • Edit or repair any messages
    • Close and run the stub again
    • Raise a defect, if necessary

    For more information about these buttons, refer to API Tester Reference.

  5. Click Close and Re-run to save your changes and to run the stub again.

    Alternatively, if running Test Integrations and APIs from memory, click Apply to save your changes and to run the stub again.

Console options

The following options are available when you right click a message case or default case message in the stub console.

Table 1. Options from pop-up menus in the stub console
Option Case Description
Open Action Message and Default Switches to the Test Factory perspective and opens the stub for editing.
Overwrite Expected Field Message Replaces the value of the specified field in the stub with the value from the incoming message. This option is available when the expected message differs from the incoming message in only a single field.
Overwrite Expected Message Message Replaces the model message in the stub with the incoming message.
Enhance stub to support this request Default Adds the incoming message to the Events list in the stub.