tests.c

#include "sarena.h"

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define TEST_PASS 0
#define TEST_FAIL 1
#define TEST_ASSERT(condition) \
    do {\
        if (!(condition)) {\
            return TEST_FAIL;\
        }\
    } while(0)

int test_arena_init_and_free(void) {
    // Create an arena and verify its member values are the expected values after initialization
    Arena arena;
    TEST_ASSERT(arena_init(&arena, 9) == 0);
    TEST_ASSERT(arena.capacity == 9);
    TEST_ASSERT(arena.size == 0);
    TEST_ASSERT(arena.data != NULL);

    // Free the arena and verify that the pointer to its data is now NULL
    arena_free(&arena);
    TEST_ASSERT(arena.data == NULL);
    TEST_ASSERT(arena.capacity == 0);
    TEST_ASSERT(arena.size == 0);

    // Attempt to allocate an arena of 900 GiB (highly unlikely system has this much)
    const size_t num_bytes = 966367641600;
    Arena arena2;
	int result = arena_init(&arena2, num_bytes);
	if (arena2.data != NULL) {
	    // This should be unreachable, but compiler will optimize it away if
        // the pointer is unused and essentially not malloc, causing it to "successfully"
        // allocate 900 GiB
		char* string1 = arena_alloc(&arena2, 6);
		string1[0] = 'E';
		string1[1] = 'R';
		string1[2] = 'R';
		string1[3] = 'O';
		string1[4] = 'R';
		string1[5] = '\0';
		fprintf(stderr, "%s\n", string1);
		fprintf(stderr, "%p\n", (void*)string1);
		return TEST_FAIL;
	}
	TEST_ASSERT(result == -1);


    return TEST_PASS;
}

int test_arena_alloc(void) {
    Arena arena;
    arena_init(&arena, 10);

    // Allocate 2 strings of length 5 bytes within the 10 byte arena
    char* string1 = arena_alloc(&arena, 5);
    TEST_ASSERT(string1 != NULL);
    char* string2 = arena_alloc(&arena, 5);
    TEST_ASSERT(string1 != NULL);

    // Try to allocate an 11th byte in the 10 byte arena, should fail
    char* too_much = arena_alloc(&arena, 1);
    TEST_ASSERT(too_much == NULL);

    // Place some data in the strings and verify with strcmp()
    memcpy(string1, "test\0", 5);
    TEST_ASSERT(strcmp(string1, "test") == 0);
    memcpy(string2, "tset\0", 5);
    TEST_ASSERT(strcmp(string2, "tset") == 0);

    // Write some more junk data to string1 and check the entire arena byte array to see if it matches what is expected
    snprintf(string1, 5, "%dt_e", 2);
    TEST_ASSERT(memcmp(arena.data, "2t_e\0tset\0", 10) == 0);

    arena_free(&arena);
    
    return TEST_PASS;
}

// Test struct. Consists of a function pointer to the test function and its test name
typedef struct {
    int (*function)(void);
    char* testname;
} Test;

int run_tests(Test tests[], int num_of_tests);

int main(void) {
    // Add test names and their function pointers here
    Test tests[] = {
        {
            .function = test_arena_init_and_free,
            .testname = "test_arena_init_and_free()"
        },
        {
            .function = test_arena_alloc,
            .testname = "test_arena_alloc()"
        },
    };

    // Get the number of tests and run them
    int num_of_tests = sizeof(tests) / sizeof(tests[0]);

    return run_tests(tests, num_of_tests);
}

int run_tests(Test tests[], int num_of_tests) {
    // Keep track of if any tests failed
    int failed = 0;
    
    for (int i = 0; i < num_of_tests; i++) {
        printf("%s: Running test..\n", tests[i].testname);
        int result = tests[i].function();
        
        if (result == TEST_PASS) {
            printf("%s: PASS\n", tests[i].testname);
        }
        else if (result == TEST_FAIL) {
            fprintf(stderr, "%s: FAIL\n", tests[i].testname);
            fflush(stderr);
            failed++;
        }
        else {
            fprintf(stderr, "ERROR: Test %s returned a value other than expected TEST_PASS or TEST_FAIL. Returned value: %d\n", tests[i].testname, result);
            fflush(stderr);
            exit(1);
        }
    }

    // Output result of all tests
    if (failed != 0) {
        fprintf(stderr, "%d/%d Tests passed, Overall result: FAIL\n", num_of_tests - failed, num_of_tests);
        fflush(stderr);
        return 1;
    }
    else {
        printf("%d/%d Tests passed, Overall result: PASS\n", num_of_tests, num_of_tests);
        return 0;
    }
}