Introduction
This might not be groundbreaking tech-news, but it could benefit someone diving into ABAP unit testing for the first time.
From time to time the result of the method under test would be an internal table. And how to use this in the assertion for unit testing? Well, calculate the hash value for the entire internal table, and voila - assertion is possible.
Method to calculate hash value
METHODS:
get_hash_value_for_itab
IMPORTING
it_table TYPE ANY TABLE
EXPORTING
ev_hash TYPE hash160.
METHOD get_hash_value_for_itab.
DATA: lv_string TYPE xstring,
lv_xbuffer TYPE xstring.
" Clear the hash value
CLEAR ev_hash.
" Go through the table one line at a time
LOOP AT it_table ASSIGNING FIELD-SYMBOL(<ls_line>).
DATA(lv_index) = 0.
CLEAR lv_string.
" Concatenate all the columns of the line into one string
DO.
ASSIGN COMPONENT lv_index OF STRUCTURE <ls_line> TO FIELD-SYMBOL(<lv_field>) CASTING TYPE x.
IF sy-subrc EQ 0.
CONCATENATE lv_string <lv_field> INTO lv_string IN BYTE MODE.
ADD 1 TO lv_index.
ELSE.
EXIT.
ENDIF.
ENDDO.
" Add the string from the line to our buffer
CONCATENATE lv_xbuffer lv_string INTO lv_xbuffer IN BYTE MODE.
ENDLOOP.
" Calculate the hash value for the entire buffer/table
CALL FUNCTION 'CALCULATE_HASH_FOR_RAW'
EXPORTING
data = lv_xbuffer
IMPORTING
hash = ev_hash
EXCEPTIONS
unknown_alg = 1
param_error = 2
internal_error = 3
OTHERS = 4.
IF sy-subrc <> 0.
" Do error handling here
ENDIF.
ENDMETHOD.
Usage of method
DATA:
lv_hash_old TYPE hash160,
lv_hash_new TYPE hash160.
me->get_hash_value_for_itab(
EXPORTING
it_table = gt_final_req
IMPORTING
ev_hash = lv_hash_old ).
IF lv_hash_old <> lv_hash_new.
“ There's a difference
ENDIF.
cl_aunit_assert=>assert_equals(
act = lv_hash
exp = '5CAF285B3FA1C3F971BBEEEE1D61EF9095B6F4CC'
msg = 'Hash value for output not correct'
).
Conclusion
When I use this I first validate that the internal table I wish to calculate hash for is correct. Then in debug I fetch the hash value for the internal table, and hardcode this into my assertion.
