Exercise 1 for CS140

The objective of this exercise is to let you practice and get familiar with the concepts of C pointers and arrays and a simple C unit test API. You should complete this exercise and test in a CSIL machine.

Download this tar ball to start. It contains Makefile, exercise.c, exercise_test.c, exercise.h, minunit.c, and minuni.h. The Makefile shows how to compile and run tests.
Your task is to
1. Read and understand the released source code.
2. Fill short C solutions to complete 5 functions in exercise.c: exchange, reverse_array, match_add, match_action, and mat_mat_mult.
3. Write the unit tests for these 5 functions in exercise_test.c, following the style of minunit tests for set_key_action and mat_vect_mult. Namely use mu_assert(), mu_run_test() and mu_print_summary(). After calling a targeted function to be tested, you donot use your own result check to report a failed case. Instead, you use mu_assert() to detect and report an error due to the mismatch of expected results.

While the number of lines needed for these 5 functions are short, you need to read all C files to understand the requirement, sample code, and the minunit test style. We will use such a test style in other parallel programming assignments. Make sure your implementation covers edge cases such as handling invalid input arguments. Common invalid arguments to consider include NULL pointers, negative array indexes, or non-positive array sizes and they may cause illegal access of memory or meaningless results.

Files minunit.h and minunit.c define macro mu_assert and two functions mu_run_test and mu_print_summary as a very simple API for C unit tests. Their usage is illustated in file exercise_test.c for testing functions set_key_action and mat_vect_mult implemented in exercise.c.

Submission Instructions

Files to submit: exercse.c and exercise_test.c. Please do not submit any additional files.

You submit the above two files through gradescope.com under Assignment "Exercise 1" (available by Jan 10). You will be invited to join Piazza around Jan 8 Thursday. We will announce the GradeScope join code in Piazza before Jan 10

Our autograding script will run your minunit test file (exercise_test) first, and then replace it with our own test file using the same Makefile. You must make sure your test file does not involve an infinite loop. You may resubmit your solution after learning the grading feedback for Exercise 1.
To avoid overloading the GradeScope server, our grading script may limit your submission at most once every 30 minutes (or smaller).

Helpful note

Here is an example of improper design in using minunit for testing set_key_action() in exercise.c

Proper use:
char * set_key_action_test(void){ char *key="del1"; int ret=set_key_action(NULL, key, del1); mu_assert("Error in set_key_action with NULL value", ret == FAIL); return NULL; }

Notice that the above test includes one case. You may add another test for another case. The released sample includes the two cases in one test.

Improper design:
char * set_key_action_test(void){ char *key="del1"; int ret=set_key_action(NULL, key, del1); if(ret==FAIL) { printf(“Something is wrong\n”); return NULL; } mu_assert("Error in set_key_action with NULL value", ret == FAIL); return NULL; }

Notice that even your own check finds there is an error, the minunit package (mu_run_test() and mu_print_summay()) does not catch this error and the summary printed would be wrong. Your unit test code should let the minunit package catch the error using mu_assert, count errors and report properly.