emscripten fileio tests

emscripten failure example

$echo 'this is a test' > testfile.txt 
$
$emcc test_fileio.c -o test_fileio.js
clang: warning: argument unused during compilation: '-nostdinc++'
$
$node test_fileio.js testfile.txt 'this is a test'
reading testfile.txt 
could not open testfile.txt 

node.js:201
        throw e; // process.nextTick error, or 'error' event on first tick
              ^
exit(1) called, at Error
    at __exit (/Users/asimmons/Development/test/emscripten/test_fileio.js:57207:50)
    at _exit (/Users/asimmons/Development/test/emscripten/test_fileio.js:57209:7)
    at _test_file_read (/Users/asimmons/Development/test/emscripten/test_fileio.js:6352:7)
    at _test_fileio (/Users/asimmons/Development/test/emscripten/test_fileio.js:6280:3)
    at _main (/Users/asimmons/Development/test/emscripten/test_fileio.js:6322:3)
    at Object.callMain (/Users/asimmons/Development/test/emscripten/test_fileio.js:57971:10)
    at run (/Users/asimmons/Development/test/emscripten/test_fileio.js:58165:18)
    at Object.<anonymous> (/Users/asimmons/Development/test/emscripten/test_fileio.js:58180:13)
    at Module._compile (module.js:441:26)
    at Object..js (module.js:459:10)
$

gcc success example

$echo 'this is a test' > testfile.txt 
$
$gcc test_fileio.c -o test_fileio
$
$./test_fileio testfile.txt 'this is a test'
reading testfile.txt 
file contents: this is a test
 
chdir to test 
reading ../testfile.txt 
file contents: this is a test
 
chdir to .. 
reading ./testfile.txt 
file contents: this is a test
 
$

test_fileio.c

/**
 * This tests a number of file io related features:
 *      - reading from files
 *      - getting a file's size
 *      - relative paths
 *      - changing the current working directory
 *      - creating/destroying files
 *      - creating/destroying directories
 *
 * It should pass using regular gcc on most POSIX systems (it probably doesn't work on Win32).
 *
 */

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

#include <unistd.h>
#include <dirent.h>
#include <sys/stat.h>

// tests
void test_chdir(const char dirname[]);
void test_mkdir(const char dirname[]);
void test_rmdir(const char dirname[]);
void test_file_read(const char filename[], const char teststr[]);
void test_file_delete(const char filename[]);

// utility function
size_t get_file_size(const char filename[]);

void test_fileio(const char filename[], const char teststr[]) {
    char filename_temp[PATH_MAX]= "";
    const char dirname[]= "test";

    strcpy(filename_temp, filename);
    test_file_read(filename_temp, teststr);

    test_mkdir(dirname);
    test_chdir(dirname);
    
    strcpy(filename_temp, "../");
    strcat(filename_temp, filename);
    test_file_read(filename_temp, teststr);

    test_chdir("..");
    
    strcpy(filename_temp, "./");
    strcat(filename_temp, filename);
    test_file_read(filename_temp, teststr);

    test_rmdir(dirname);
}

void test_chdir(const char dirname[]) {
    printf("chdir to %s \n", dirname);

    int ret= 0;
    char cwd_orig[PATH_MAX]= "", cwd_new[PATH_MAX]= "";

    getcwd(cwd_orig, sizeof(cwd_orig));
    if (strlen(cwd_orig) == 0) {
        printf("get cwd failed \n");
        exit(1);
    }

    ret= chdir(dirname);
    if (ret != 0) {
        printf("unable to change dir to %s \n", dirname);
        exit(1);
    }

    getcwd(cwd_new, sizeof(cwd_new));
    if (strlen(cwd_new) == 0) {
        printf("get cwd failed \n");
        exit(1);
    }

    if (strncmp(cwd_new, cwd_orig, sizeof(cwd_new)) == 0) {
        printf("we're probably not running in root \n");
        exit(1);
    }
}

void test_mkdir(const char dirname[]) {
    int ret= mkdir(dirname, 0777);
    if (ret != 0) {
        printf("unable to make dir %s \n", dirname);
        exit(1);
    }

    DIR *dir= opendir(dirname);
    if (dir == NULL) {
        printf("unable to open dir %s \n", dirname);
        exit(1);
    }
    closedir(dir);
}

void test_rmdir(const char dirname[]) {
    int ret= rmdir(dirname);
    if (ret != 0) {
        exit(1);
    }
    
    DIR *dir= opendir(dirname);
    if (dir != NULL) {
        printf("able to open %s even tho its deleted \n", dirname);
        exit(1);
    }
}

void test_file_read(const char filename[], const char teststr[]) {
    printf("reading %s \n", filename);    

    FILE *file= fopen(filename, "r");
    if (file == NULL) {
        printf("could not open %s \n", filename);
        exit(1);
    }

    // slurp the file
    int filesize= get_file_size(filename);
    char *filestr= (char*)malloc(filesize + sizeof(char));
    memset(filestr, 0, filesize);
    fread(filestr, 1, filesize, file);

    printf("file contents: %s \n", filestr);

    // make sure the file's contents match the test string
    if (strncmp(filestr, teststr, strlen(teststr)) != 0) {
        printf("expected \"%s\" but was \"%s\" \n", teststr, filestr);
        exit(1);
    }
    
    free(filestr);
    fclose(file);
}

size_t get_file_size(const char filename[]) {
    struct stat stbuf;
    if (stat(filename, &stbuf) == -1) {
        fprintf(stdout, "can't stat %s \n", filename);
        exit(1);
    }
    return stbuf.st_size;
}

int main(int argc, char *argv[]) {
    test_fileio(argv[1], argv[2]);
    return 0;
}