Development and validation of a safe communication protocol compliant to railway standards

Table 5 An example test case showing the unit test of the CRC generation function

Test case ID	crc_ch1
Priority	Medium
Description	CRC generation function
Module	Safety layer
Prepared by		Date prepared
Reviewed/updated		Date reviewed
Tested by		Date tested
Software version
Test activities
Sl. no.	Step description	Expected results
1	Definition of the input data
2	if the input data are plausibles: • Computation of the CRC using an external tool and comparation with the result obtained using the internal function otherwise: • Verification of the correct error handling and report	The code obtained using the external tool and the internal function must be equals
Test data sets
Data type	Data set 1	Data set 2	Data set 3
uint8_t input[];	input ={0,0,0,0,0,0,0,0}	input = {0xffff, 0xffff, 0xffff, 0xffff}	input = {‘C’,’o’,’n’,’t’,’r’,’o’,’l’ }
uint16_t size;	size = 8	size = 4	size = 0
Actual results
Data type	Data set 4	Data set 5	Data set 6
uint8_t input[];	input = NULL	input = {0,0,0,0,0,0,0,0}
uint16_t size;	size=0	size = − 1
Actual results
Test case result

Data sets 2 and 4 are robustness tests that invoke the function with values bigger than expected (using 16-bit unsigned integers in place of the 8-bit requested) and with NULL parameters