creating test-doubles for AMDP classes

[bunysae]

Introduction

AMDP classes wrap database procedures written in SQLScript or Native SQL.
The table entities used in Open SQL statments can be replaced by test-doubles with the Open SQL replacement service. Table entities used in SQLScript or Native SQL statements can't be replaced with this service. If the AMDP class doesn't implement a CDS table function, we can't use the CDS Test Double Framework. So a suitable solution is the ABAP Test Double Framework.

AMDP classes

AMDP classes are in principle normal ABAP classes with a few particularities:

• They were thought for database procedures, which can't be easily implemented in Open SQL or in ABAP-CDS


• They must implement a database specific tag interface (IF_AMDP_MARKER_ + suffix for database system):
  
  
  
  • IF_AMDP_MARKER_HDB for HANA databases
  
  
  
  This concept can be expanded to other database systems, but HANA is the only supported database for now.


• They contain AMDP methods, which implement the database procedures

AMDP methods

AMDP methods require a specific parameter interface:

• only elementary data types or tables types with a elementary row type are supported


• parameters must be passed by value


• no return parameters can be declared


• the implementation can't be empty

A sample AMDP class can be seen below.

INTERFACE zif_flight_accessor

  PUBLIC .



  METHODS increase_price

    IMPORTING

      VALUE(clnt)      TYPE sy-mandt

      VALUE(carrid)    TYPE s_carr_id

      VALUE(connid)    TYPE s_conn_id

      VALUE(fldate)    TYPE s_date

      VALUE(increment) TYPE sflight-price.

ENDINTERFACE.

 

CLASS zflight_accessor DEFINITION

  PUBLIC

  FINAL

  CREATE PUBLIC .



  PUBLIC SECTION.



    INTERFACES zif_flight_accessor .

    INTERFACES if_amdp_marker_hdb.

    

  PROTECTED SECTION.

  PRIVATE SECTION.

ENDCLASS.



CLASS zflight_accessor IMPLEMENTATION.



  METHOD zif_flight_accessor~increase_price

    BY DATABASE PROCEDURE FOR HDB

                        LANGUAGE SQLSCRIPT

                        USING sflight.



    update sflight set price = price + :increment

                   where mandt = :clnt and carrid = :carrid

                   and connid = :connid and fldate = :fldate;



  ENDMETHOD.



ENDCLASS.

AMDP methods can be called like any other method. For this reason, the AMDP method INCREASE_PRICE in class ZFLIGHT_ACCESSOR is packed behind an interface. When an AMDP method can be called like any other method, it's possible to create a test-double with the ABAP Test Double Framework.

A simple test-double for INCREASE_PRICE is created like this:

increase_price_test_double ?= cl_abap_testdouble=>create( object_name = 'ZIF_FLIGHT_ACCESSOR' ).

cl_abap_testdouble=>configure_call( increase_price_test_double )->and_expect( )->is_called_once( ).

increase_price_test_double->increase_price( clnt = sy-mandt increment = 10

  carrid = 'TG' connid = 924 fldate = '20200420' ).

This creates a mock with the expectation INCREASE_PRICE is called once with the parameters:

• 
  
  
  
  • increment = 10
  
  
  • carrid = 'TG'
  
  
  • connid = 924
  
  
  • fldate = '20200420'
  
  
  
  

.

The expectation can be verified with the statement cl_abap_testdouble=>verify_expectations( increase_price_test_double ).

Conclusion

Instead of replacing a table entity with the OpenSQL replacement service, we can replace the AMDP class by an test-double. This approach doesn't cover the SQL statements, but it can be helpful for creating deterministic unit tests.