ABAP_to_the_Future

Writing and Implementing Unit Tests 3.3
왘 Helper methods that call one or more ABAP statements for the sole purpose of
making the core test method read like plain English
Inside each unit test method (the methods that end with FOR TESTING), you will
have several helper methods with names that have come straight out of the specification.
As an example, the specification document says that the main purpose
of the program is to return a bill of materials (BOM) for a monster, and you do
that by having the user enter various desired monster criteria, which are then
used to calculate the BOM according to certain rules. This can be boiled down
into three sentences, and you can create helper methods with the same names as
those sentences, as shown in Listing 3.12.
given_monster_details_entered,
when_bom_is_calculated,
then_resulting_bom_is_correct,
Listing 3.12 Defining Helper Methods to Be Used in Test Methods
A method can of course do two things athe same time: hide boiler plate code and
make the remaining code look more like English. Ahead, you’ll see such an example;
you’re going to be looking up the BOM again and again in various tests, and
you do not want the reader of the test to be distracted by the mechanics of reading
from an internal table. In addition, you want the tests to read like English sentences,
so if you use a single IMPORTING parameter and a RETURNING parameter,
then you will be able to refer to BOM_LINE_ITEM( 5 ), which, although not quite
grammatically perfect, makes it clear enough to the reader what is being referred
to. The code for this is shown in Listing 3.13.
*--------------------------------------------------------------*
* Helper Methods
*--------------------------------------------------------------*
bom_line_item
IMPORTING id_line_number TYPE sy-tabix
RETURNING VALUE(rs_bom_line) LIKE LINE OF mt_bom_table.
ENDCLASS. "Test Class Definition
Listing 3.13 Helper Method to Query a BOM Line Item
3.3.2 Implementing Test Classes
Now that you’ve defined the test class, you can go ahead with the process of
implementing it. At the end of this step, you’ll be able to show the business
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