There are several ways to test the correct functioning of a mapping transformation:

1. In the Mapping Designer:
   1. with automatically generated test data
   2. Based on an existing file¹⁾ in the mapping editor
   3. Based on an existing file with multiple entities via analyzer ²⁾ in the mapping editor
   4. From a backend object ³⁾ in the mapping editor.
   5. Testing Transformation Chains
2. In the message basket:
   1. Starting from an existing and analyzed message⁴⁾

To use debugging in the Mapping Designer, the source object must first be instantiated. Choose in the upper left area of the mapping definition view. Debugging Menu.

This offers four different options for object instantiation.

In the mapping definition view, select in the upper left area. Debugging Menu the entry Generate test data. This automatically generates an object instance in the source object with data element-specific content and three instances per ArrayList item. Test data can be used to quickly check whether the transformation produces the desired results.

In the mapping definition view, select in the upper left area. Debugging Menu the entry load from file off. If the file selected in the following file selection dialog contains an entity that fits into the source object, it will be instantiated with the contents of the file.

This method is useful if source files contain several entities of the source object. In the mapping definition view, select in the upper left area. Debugging Menu the entry Load via analyzer off. First the desired analyzer is selected and confirmed with OK, with the following file selection dialog the desired file is selected. If the file can be successfully analyzed with the selected analyzer, a list of entities will be offered in the following dialog from which one can now select one and confirm with OK.

Note: If a message contains several entities, they can be selected with multiple selection and instantiated as source. This makes it possible to make groupings or evaluations and conversions beyond the entity context.

This method is useful if the data source can be operated via database integration. In the mapping definition view, choose in the upper left area. Debugging Menu the entry Load from BackendObject off.

If a target object is successfully instantiated and the system has a mapping with this target type as source type, you can go directly to a new mapping designer instance with the instantiated target. In the mapping definition view in the *right upper area select from the debugging menu the menu entry Debug with other mapping *out.

You can access the debugging of mappings directly from messages. So if a message is selected in the list of messages you can use the context menu

via Debug message * ► debug mapping or in the detail view of a message via the menu

the content of the message as source object of a mapping with the menu entry debug mapping * instantiate.

Note: Only if the message has already been successfully analyzed. Otherwise

Once you have instantiated the source object, you can translate to the target by removing the following from debugging menu the first menu entry Apply mapping⁵⁾. The input values are then output in the source object (left side) and the output values in the target object (right side).

The status bar⁶⁾ gives a first feedback about success or failure of the transformation via coloring.

1. It is green for success:
   
2. It's yellow on warnings:
   
3. It is red on error:
   

All translation steps are displayed in a log window, but this must first be displayed via the button in the status bar⁷⁾.

With the XPath query individual selections can be tested for the source instance.

If errors occur, the entries of the objects where an error occurred are marked red in the log window with object name and error description. The error description can then be used to locate and correct incorrect links.

If a more complex error output is required, a separate CustomErrorExpression can be defined in the map editor for each mapping rule under element-properties. This must also be a XPath-Expression e.g. :

concat('At position: ', $position,' missing the EAN!')