diff --git a/.gitignore b/.gitignore
index 7cb052c..2145860 100644
--- a/.gitignore
+++ b/.gitignore
@@ -9,3 +9,4 @@ a.out
 *.o
 *.4coder
 *.rdbg
+test_folder/
\ No newline at end of file
diff --git a/test/crt_functions.c b/test/crt_functions.c
index 1bdd2be..971da06 100644
--- a/test/crt_functions.c
+++ b/test/crt_functions.c
@@ -1,545 +1,605 @@
-
-// Framework for testing of the CRT library. This file is supposed to be linked
-// to the ciabatta, so there is a possibility that the runtime that the testing
-// suite relies on is broken, which is why to decrease the chance of it crashing
-// because of that, I minimize that dependency. Therefore this testing suite
-// avoids the following:
-// - Heap allocations
-// - Calls to high-level functions like printf, preferring low-level fwrite instead
-// - Calling other CRT functions other than for the purpose of testing them
-
-// Dependencies
-#include <stddef.h>
-#include <stdio.h>
-#include <stdbool.h>
-#include <stdarg.h>
-#include <stdint.h>
-
-// Tested
-#include <stdint.h>
-#include <limits.h>
-#include <ctype.h>
-
-#define TEST_MEMORY_SIZE 8*1024*1024
-static uint8_t test_memory[TEST_MEMORY_SIZE];
-static uint64_t test_memory_head = TEST_MEMORY_SIZE;
-
-static void *mem_alloc(uint64_t size) {
-    if(test_memory_head < size) {
-        fputs("Out of memory. Can't continue testing!!", stderr);
-        return NULL;
-    }
-    test_memory_head -= size;
-    return &test_memory[test_memory_head];
-}
-
-static unsigned long random_seed = 0;
-
-unsigned long random(void) {
-   random_seed = random_seed * 2147001325 + 715136305;
-   return 0x31415926 ^ ((random_seed >> 16) + (random_seed << 16));
-}
-
-unsigned long random_between(int lo, int hi) {
-    return (random() % (1+hi - lo)) + lo;
-}
-
-static void printc(char c) {
-    putchar(c);
-}
-
-static void prints(char *str) {
-    while(*str != 0) {
-        printc(*str++);
-    }
-}
-
-static void printd(int32_t number) {
-    if(number < 0) {
-        putchar('-');
-        number = -number;
-    }
-    char buffer[20] = {0};
-    char *str = buffer + sizeof buffer;
-    do {
-        *--str = number%10+'0';
-        number /= 10;
-    } while(number != 0);
-    prints(str);
-}
-
-static void printu(uint32_t number) {
-    char buffer[20] = {0};
-    char *str = buffer + sizeof buffer;
-    do {
-        *--str = number%10+'0';
-        number /= 10;
-    } while(number != 0);
-    prints(str);
-}
-
-static void print_fmt(char *fmt, ...) {
-    va_list args;
-    va_start(args, fmt);
-    while(*fmt != 0) {
-        if(*fmt != '%') {
-            printc(*fmt);
-        }
-        else {
-            ++fmt;
-            if(*fmt == 'c') {
-                int ch = va_arg(args, int);
-                printc(ch);
-            }
-            else if(*fmt == '%') {
-                printc('%');
-            }
-            else if(*fmt == 's') {
-                char *str = va_arg(args, char*);
-                prints(str);
-            }
-            else if(*fmt == 'd') {
-                int32_t i = va_arg(args, int32_t);
-                printd(i);
-            }
-            else if(*fmt == 'u') {
-                uint32_t u = va_arg(args, uint32_t);
-                printu(u);
-            }
-        }
-        ++fmt;
-    }
-    va_end(args);
-}
-
-static void sprint_fmt(char *dst, char *fmt, ...) {
-    va_list args;
-    va_start(args, fmt);
-    while(*fmt != 0) {
-        if(*fmt != '%') {
-            *dst++ = *fmt;
-        }
-        else {
-            ++fmt;
-            if(*fmt == 'c') {
-                int ch = va_arg(args, int);
-                *dst++ = ch;
-            }
-            else if(*fmt == 's') {
-                char *str = va_arg(args, char*);
-                while((*dst++ = *str++));
-            }
-            else if(*fmt == 'd') {
-                int32_t i = va_arg(args, int32_t);
-                if(i < 0) {
-                    i = -i;
-                    *dst++ = '-';
-                }
-                char buffer[20] = {0};
-                char *str = buffer + sizeof buffer;
-                do {
-                    *--str = i%10+'0';
-                    i /= 10;
-                } while(i != 0);
-                while((*dst++ = *str++));
-            }
-            else if(*fmt == 'u') {
-                uint32_t u = va_arg(args, uint32_t);
-                char buffer[20] = {0};
-                char *str = buffer + sizeof buffer;
-                do {
-                    *--str = u%10+'0';
-                    u /= 10;
-                } while(u != 0);
-                while((*dst++ = *str++));                
-            }
-        }
-        ++fmt;
-    }
-    *dst = 0;
-    va_end(fmt);
-}
-
-static void term_color_green() {
-    prints("\x1b[32m");
-}
-
-static void term_color_red() {
-    prints("\x1b[31m");
-}
-
-static void term_color_yellow() {
-    prints("\x1b[33m");
-}
-
-static void term_color_reset() {
-    prints("\x1b[0m");
-}
-
-// This stuff is for saving results of tests to be a bit more flexible with printing
-// test results
-struct Test typedef Test;
-struct Test_Feature typedef Test_Feature;
-
-struct Test_Feature {
-    Test_Feature *next;
-    char *name;
-    int test_count;
-    int success_count;
-    Test *test_head;
-};
-
-struct Test {
-    Test *next;
-    char *condition_str;
-    char *error_msg;
-    bool is_succeeded;
-};
-
-static void print_test_results(Test_Feature *features_head) {
-    int total_test_count = 0;
-    int total_success_count = 0;
-    for(Test_Feature *feature = features_head; feature != NULL; feature = feature->next) {
-        total_test_count += feature->test_count;
-        total_success_count += feature->success_count;
-        term_color_green();
-        print_fmt("==> Feature ");
-        term_color_reset();
-        print_fmt("%s: (%d/%d)\n", feature->name, feature->success_count, feature->test_count);
-        if(feature->success_count < feature->test_count) {
-            int test_index = 0;
-            for(Test *test = feature->test_head; test != NULL; test = test->next) {
-                if(!test->is_succeeded) {
-                    term_color_red();
-                    print_fmt("  Test #%d", 1+test_index);
-                    term_color_reset();
-                    print_fmt(" failed: %s\n", test->error_msg);
-                }
-                test_index += 1;
-            }
-        }
-        float success_percentage = (float) total_success_count / (float)total_test_count;
-        if(success_percentage < 0.5) {
-            term_color_red();
-        }
-        else if(success_percentage != 1.0) {
-            term_color_yellow();
-        }
-        else {
-            term_color_green();
-        }
-    }
-    prints("TESTS COMPLETED: ");
-    printd(total_success_count);
-    printc('/');
-    printd(total_test_count);
-    term_color_reset();
-    printc('\n');
-}
-
-#define XSTR(expr) #expr
-#define STR(expr) XSTR(expr)
-
-Test_Feature *current_feature = NULL;
-
-#define FEATURE_START__(NAME, NUMBER) \
-    { \
-        Test_Feature *feature = mem_alloc(sizeof(Test_Feature)); \
-        feature->next = current_feature; \
-        current_feature = feature; \
-        current_feature->name = NAME; \
-        current_feature->test_head = NULL; \
-        current_feature->success_count = 0; \
-        current_feature->test_count = 0; \
-    }
-
-#define FEATURE_START_(NAME, NUMBER) \
-    FEATURE_START__(NAME, NUMBER)    
-
-#define FEATURE_START(NAME) \
-    FEATURE_START_(NAME, __COUNTER__)
-
-#define FEATURE_END()
-
-#define TEST__(EXPR, ERROR_FMT, NUMBER, ...) \
-    { \
-        Test *test = mem_alloc(sizeof(Test)); \
-        test->next = current_feature->test_head; \
-        current_feature->test_head = test; \
-        current_feature->test_head->condition_str = STR(EXPR); \
-        current_feature->test_head->is_succeeded = EXPR; \
-        if(current_feature->test_head->is_succeeded) {\
-            current_feature->success_count += 1; \
-        }\
-        else { \
-            current_feature->test_head->error_msg = mem_alloc(256); \
-            sprint_fmt(current_feature->test_head->error_msg, ERROR_FMT, __VA_ARGS__); \
-        }\
-        current_feature->test_count += 1; \
-    }
-
-#define TEST_(EXPR, ERROR_MSG, NUMBER, ...) \
-    TEST__(EXPR, ERROR_MSG, NUMBER, __VA_ARGS__)
-
-#define TEST(EXPR, ERROR_MSG, ...) \
-    TEST_(EXPR, ERROR_MSG, __COUNTER__, __VA_ARGS__)
-
-#define TESTS_PRINT_RESULT() \
-    print_test_results(current_feature)
-
-int main(int argc, char **argv) {
-    FEATURE_START("limits.h");
-    {
-        // Check existing of macro definitions
-        #ifdef BOOL_WIDTH
-            TEST(BOOL_WIDTH == 8*sizeof(bool), "BOOL_WIDTH isn't correlated with sizeof(bool)");
-        #else
-            TEST(false, "The macro BOOL_WIDTH wasn't defined");
-        #endif
-        #ifdef CHAR_WIDTH
-            TEST(CHAR_WIDTH == 8, "CHAR_WIDTH isn't 8");
-        #else
-            TEST(false, "The macro CHAR_WIDTH wasn't defined");
-        #endif
-        #ifdef CHAR_BIT
-            TEST(CHAR_BIT == 8, "CHAR_BIT isn't 8");
-        #else
-            TEST(false, "The macro CHAR_BIT wasn't defined");
-        #endif
-        #ifdef CHAR_MIN
-            TEST(CHAR_MIN == -128, "CHAR_MIN isn't -128");
-        #else
-            TEST(false, "The macro CHAR_MIN wasn't defined");
-        #endif
-        #ifdef CHAR_MAX
-            TEST(CHAR_MAX == 127, "CHAR_MAX isn't 127");
-        #else
-            TEST(false, "The macro CHAR_MAX wasn't defined");
-        #endif
-        #ifdef MB_LEN_MAX
-            TEST(true, "");
-        #else
-            TEST(false, "The macro MB_LEN_MAX wasn't defined");
-        #endif
-        
-        #ifdef SCHAR_WIDTH
-            TEST(SCHAR_WIDTH == 8, "SCHAR_WIDTH isn't 8");
-        #else
-            TEST(false, "The macro SCHAR_WIDTH wasn't defined");
-        #endif
-        #ifdef SHRT_WIDTH
-            TEST(SHRT_WIDTH == 16, "SHRT_WIDTH isn't 16");
-        #else
-            TEST(false, "The macro SHRT_WIDTH wasn't defined");
-        #endif
-        #ifdef INT_WIDTH
-            TEST(INT_WIDTH == 32, "INT_WIDTH isn't 32");
-        #else
-            TEST(false, "The macro INT_WIDTH wasn't defined");
-        #endif
-        #ifdef LONG_WIDTH
-            TEST(LONG_WIDTH == 32, "LONG_WIDTH isn't 32");
-        #else
-            TEST(false, "The macro LONG_WIDTH wasn't defined");
-        #endif
-        #ifdef LLONG_WIDTH
-            TEST(LLONG_WIDTH == 64, "LLONG_WIDTH isn't 64");
-        #else
-            TEST(false, "The macro LLONG_WIDTH wasn't defined");
-        #endif
-        
-        #ifdef SCHAR_MIN
-            TEST(SCHAR_MIN == -128, "SCHAR_MIN isn't -128");
-        #else
-            TEST(false, "The macro SCHAR_MIN wasn't defined");
-        #endif
-        #ifdef SHRT_MIN
-            TEST(SHRT_MIN == -0x8000, "SHRT_MIN isn't -0x8000");
-        #else
-            TEST(false, "The macro SHRT_MIN wasn't defined");
-        #endif
-        #ifdef INT_MIN
-            TEST(INT_MIN == -0x80000000, "INT_MIN isn't -0x80000000");
-        #else
-            TEST(false, "The macro INT_MIN wasn't defined");
-        #endif
-        #ifdef LONG_MIN
-            TEST(LONG_MIN == -0x80000000l, "LONG_MIN isn't -0x80000000");
-        #else
-            TEST(false, "The macro LONG_MIN wasn't defined");
-        #endif
-        #ifdef LLONG_MIN
-            TEST(LLONG_MIN == -0x8000000000000000ll, "LLONG_MIN isn't -0x8000000000000000");
-        #else
-            TEST(false, "The macro LLONG_MIN wasn't defined");
-        #endif
-        
-        #ifdef SCHAR_MAX
-            TEST(SCHAR_MAX == 127, "SCHAR_MAX isn't 127");
-        #else
-            TEST(false, "The macro SCHAR_MAX wasn't defined");
-        #endif
-        #ifdef SHRT_MAX
-            TEST(SHRT_MAX == 0x7fff, "SHRT_MAX isn't 0x7fff");
-        #else
-            TEST(false, "The macro SHRT_MAX wasn't defined");
-        #endif
-        #ifdef INT_MAX
-            TEST(INT_MAX == 0x7fffffff, "INT_MAX isn't 0x7fffffff");
-        #else
-            TEST(false, "The macro INT_MAX wasn't defined");
-        #endif
-        #ifdef LONG_MAX
-            TEST(LONG_MAX == 0x7fffffff, "LONG_MAX isn't 0x7fffffff");
-        #else
-            TEST(false, "The macro LONG_MAX wasn't defined");
-        #endif
-        #ifdef LLONG_MAX
-            TEST(LLONG_MAX == 0x7fffffffffffffffll, "LLONG_MAX isn't 0x7fffffffffffffff");
-        #else
-            TEST(false, "The macro LLONG_MAX wasn't defined");
-        #endif
-        
-        #ifdef UCHAR_WIDTH
-            TEST(UCHAR_WIDTH == 8, "UCHAR_WIDTH isn't 8");
-        #else
-            TEST(false, "The macro UCHAR_WIDTH wasn't defined");
-        #endif
-        #ifdef USHRT_WIDTH
-            TEST(USHRT_WIDTH == 16, "USHRT_WIDTH isn't 16");
-        #else
-            TEST(false, "The macro USHRT_WIDTH wasn't defined");
-        #endif
-        #ifdef UINT_WIDTH
-            TEST(UINT_WIDTH == 32, "UINT_WIDTH isn't 32");
-        #else
-            TEST(false, "The macro UINT_WIDTH wasn't defined");
-        #endif
-        #ifdef ULONG_WIDTH
-            TEST(ULONG_WIDTH == 32, "ULONG_WIDTH isn't 32");
-        #else
-            TEST(false, "The macro ULONG_WIDTH wasn't defined");
-        #endif
-        #ifdef ULLONG_WIDTH
-            TEST(ULLONG_WIDTH == 64, "ULLONG_WIDTH isn't 64");
-        #else
-            TEST(false, "The macro ULLONG_WIDTH wasn't defined");
-        #endif
-        
-        #ifdef UCHAR_MAX
-            TEST(UCHAR_MAX == 255, "UCHAR_MAX isn't 255");
-        #else
-            TEST(false, "The macro UCHAR_MAX wasn't defined");
-        #endif
-        #ifdef USHRT_MAX
-            TEST(USHRT_MAX == 0xffffu, "USHRT_MAX isn't 0xffff");
-        #else
-            TEST(false, "The macro USHRT_MAX wasn't defined");
-        #endif
-        #ifdef UINT_MAX
-            TEST(UINT_MAX == 0xffffffffu, "UINT_MAX isn't 0xffffffff");
-        #else
-            TEST(false, "The macro UINT_MAX wasn't defined");
-        #endif
-        #ifdef ULONG_MAX
-            TEST(ULONG_MAX == 0xffffffffu, "ULONG_MAX isn't 0xffffffff");
-        #else
-            TEST(false, "The macro ULONG_MAX wasn't defined");
-        #endif
-        #ifdef ULLONG_MAX
-            TEST(ULLONG_MAX == 0xffffffffffffffffull, "ULLONG_MAX isn't 0xffffffffffffffffull");
-        #else
-            TEST(false, "The macro ULLONG_MAX wasn't defined");
-        #endif
-            
-        #ifdef PTRDIFF_WIDTH
-            TEST(true, "");
-        #else
-            TEST(false, "The macro PTRDIFF_WIDTH isn't defined");
-        #endif
-        #ifdef PTRDIFF_MIN
-            TEST(true, "");
-        #else
-            TEST(false, "The macro PTRDIFF_MIN isn't defined");
-        #endif
-        #ifdef PTRDIFF_MAX
-            TEST(true, "");
-        #else
-            TEST(false, "The macro PTRDIFF_MAX isn't defined");
-        #endif
-        #ifdef SIZE_WIDTH
-            TEST(true, "");
-        #else
-            TEST(false, "The macro SIZE_WIDTH isn't defined");
-        #endif
-        #ifdef SIZE_MAX
-            TEST(true, "");
-        #else
-            TEST(false, "The macro SIZE_MAX isn't defined");
-        #endif
-        #ifdef SIG_ATOMIC_WIDTH
-            TEST(true, "");
-        #else
-            TEST(false, "The macro SIG_ATOMIC_WIDTH isn't defined");
-        #endif
-            #ifdef SIG_ATOMIC_MIN
-            TEST(true, "");
-        #else
-            TEST(false, "The macro SIG_ATOMIC_MIN isn't defined");
-        #endif
-            #ifdef SIG_ATOMIC_MAX
-            TEST(true, "");
-        #else
-            TEST(false, "The macro SIG_ATOMIC_MAX isn't defined");
-        #endif
-        #ifdef WINT_WIDTH
-            TEST(true, "");
-        #else
-            TEST(false, "The macro WINT_WIDTH isn't defined");
-        #endif
-            #ifdef WINT_MIN
-            TEST(true, "");
-        #else
-            TEST(false, "The macro WINT_MIN isn't defined");
-        #endif
-            #ifdef WINT_MAX
-            TEST(true, "");
-        #else
-            TEST(false, "The macro WINT_MAX isn't defined");
-        #endif
-        #ifdef WCHAR_WIDTH
-            TEST(true, "");
-        #else
-            TEST(false, "The macro WCHAR_WIDTH isn't defined");
-        #endif
-        #ifdef WCHAR_MIN
-            TEST(true, "");
-        #else
-            TEST(false, "WCHAR_MIN isn't defined");
-        #endif
-            #ifdef WCHAR_MAX
-            TEST(true, "");
-        #else
-            TEST(false, "WCHAR_MAX isn't defined");
-        #endif
-    }
-    FEATURE_END();
-
-    FEATURE_START("ctype.h");
-        // Test letters
-        for(int i = 0; i != 10; ++i) {
-            int letter = random_between('a', 'z');
-            TEST(isalpha(letter) != 0, "isalpha('%c') returned false", letter);
-            TEST(isdigit(letter) == 0, "isdigit('%c') returned true", letter);
-        }
-        // Test digits
-        for(int i = 0; i != 10; ++i) {
-            int digit = random_between('0', '9');
-            TEST(isalpha(digit) == 0, "isalpha('%c') returned true", digit);
-            TEST(isdigit(digit) != 0, "isdigit('%c') returned false", digit);
-        }
-    FEATURE_END();
-
-    TESTS_PRINT_RESULT();
-    return 0;
-}
+
+// Framework for testing of the CRT library. This file is supposed to be linked
+// to the ciabatta, so there is a possibility that the runtime that the testing
+// suite relies on is broken, which is why to decrease the chance of it crashing
+// because of that, I minimize that dependency. Therefore this testing suite
+// avoids the following:
+// - Heap allocations
+// - Calls to high-level functions like printf, preferring low-level fwrite instead
+// - Calling other CRT functions other than for the purpose of testing them
+
+// Dependencies
+#include <stddef.h>
+#include <stdio.h>
+#include <stdbool.h>
+#include <stdarg.h>
+#include <stdint.h>
+
+// Tested
+#include <stdint.h>
+#include <limits.h>
+#include <ctype.h>
+
+#define TEST_MEMORY_SIZE 8*1024*1024
+static uint8_t test_memory[TEST_MEMORY_SIZE];
+static uint64_t test_memory_head = TEST_MEMORY_SIZE;
+
+static void *mem_alloc(uint64_t size) {
+    if(test_memory_head < size) {
+        fputs("Out of memory. Can't continue testing!!", stderr);
+        return NULL;
+    }
+    test_memory_head -= size;
+    return &test_memory[test_memory_head];
+}
+
+static unsigned long random_seed = 0;
+
+unsigned long random(void) {
+   random_seed = random_seed * 2147001325 + 715136305;
+   return 0x31415926 ^ ((random_seed >> 16) + (random_seed << 16));
+}
+
+unsigned long random_between(int lo, int hi) {
+    return (random() % (1+hi - lo)) + lo;
+}
+
+static void printc(char c) {
+    putchar(c);
+}
+
+static void prints(char *str) {
+    while(*str != 0) {
+        printc(*str++);
+    }
+}
+
+static void printd(int32_t number) {
+    if(number < 0) {
+        putchar('-');
+        number = -number;
+    }
+    char buffer[20] = {0};
+    char *str = buffer + sizeof buffer;
+    do {
+        *--str = number%10+'0';
+        number /= 10;
+    } while(number != 0);
+    prints(str);
+}
+
+static void printu(uint32_t number) {
+    char buffer[20] = {0};
+    char *str = buffer + sizeof buffer;
+    do {
+        *--str = number%10+'0';
+        number /= 10;
+    } while(number != 0);
+    prints(str);
+}
+
+static void print_fmt(char *fmt, ...) {
+    va_list args;
+    va_start(args, fmt);
+    while(*fmt != 0) {
+        if(*fmt != '%') {
+            printc(*fmt);
+        }
+        else {
+            ++fmt;
+            if(*fmt == 'c') {
+                int ch = va_arg(args, int);
+                printc(ch);
+            }
+            else if(*fmt == '%') {
+                printc('%');
+            }
+            else if(*fmt == 's') {
+                char *str = va_arg(args, char*);
+                prints(str);
+            }
+            else if(*fmt == 'd') {
+                int32_t i = va_arg(args, int32_t);
+                printd(i);
+            }
+            else if(*fmt == 'u') {
+                uint32_t u = va_arg(args, uint32_t);
+                printu(u);
+            }
+        }
+        ++fmt;
+    }
+    va_end(args);
+}
+
+static void sprint_fmt(char *dst, char *fmt, ...) {
+    va_list args;
+    va_start(args, fmt);
+    while(*fmt != 0) {
+        if(*fmt != '%') {
+            *dst++ = *fmt;
+        }
+        else {
+            ++fmt;
+            if(*fmt == 'c') {
+                int ch = va_arg(args, int);
+                *dst++ = ch;
+            }
+            else if(*fmt == 's') {
+                char *str = va_arg(args, char*);
+                while((*dst++ = *str++));
+            }
+            else if(*fmt == 'd') {
+                int32_t i = va_arg(args, int32_t);
+                if(i < 0) {
+                    i = -i;
+                    *dst++ = '-';
+                }
+                char buffer[20] = {0};
+                char *str = buffer + sizeof buffer;
+                do {
+                    *--str = i%10+'0';
+                    i /= 10;
+                } while(i != 0);
+                while((*dst++ = *str++));
+            }
+            else if(*fmt == 'u') {
+                uint32_t u = va_arg(args, uint32_t);
+                char buffer[20] = {0};
+                char *str = buffer + sizeof buffer;
+                do {
+                    *--str = u%10+'0';
+                    u /= 10;
+                } while(u != 0);
+                while((*dst++ = *str++));                
+            }
+        }
+        ++fmt;
+    }
+    *dst = 0;
+    va_end(fmt);
+}
+
+static void term_color_green() {
+    prints("\x1b[32m");
+}
+
+static void term_color_red() {
+    prints("\x1b[31m");
+}
+
+static void term_color_yellow() {
+    prints("\x1b[33m");
+}
+
+static void term_color_reset() {
+    prints("\x1b[0m");
+}
+
+// This stuff is for saving results of tests to be a bit more flexible with printing
+// test results
+struct Test typedef Test;
+struct Test_Feature typedef Test_Feature;
+
+struct Test_Feature {
+    Test_Feature *next;
+    char *name;
+    int test_count;
+    int success_count;
+    Test *test_head;
+};
+
+struct Test {
+    Test *next;
+    char *condition_str;
+    char *error_msg;
+    bool is_succeeded;
+};
+
+static void print_test_results(Test_Feature *features_head) {
+    int total_test_count = 0;
+    int total_success_count = 0;
+    for(Test_Feature *feature = features_head; feature != NULL; feature = feature->next) {
+        total_test_count += feature->test_count;
+        total_success_count += feature->success_count;
+        term_color_green();
+        print_fmt("==> Feature ");
+        term_color_reset();
+        print_fmt("%s: (%d/%d)\n", feature->name, feature->success_count, feature->test_count);
+        if(feature->success_count < feature->test_count) {
+            int test_index = 0;
+            for(Test *test = feature->test_head; test != NULL; test = test->next) {
+                if(!test->is_succeeded) {
+                    term_color_red();
+                    print_fmt("  Test #%d", 1+test_index);
+                    term_color_reset();
+                    print_fmt(" failed: %s\n", test->error_msg);
+                }
+                test_index += 1;
+            }
+        }
+        float success_percentage = (float) total_success_count / (float)total_test_count;
+        if(success_percentage < 0.5) {
+            term_color_red();
+        }
+        else if(success_percentage != 1.0) {
+            term_color_yellow();
+        }
+        else {
+            term_color_green();
+        }
+    }
+    prints("TESTS COMPLETED: ");
+    printd(total_success_count);
+    printc('/');
+    printd(total_test_count);
+    term_color_reset();
+    printc('\n');
+}
+
+#define XSTR(expr) #expr
+#define STR(expr) XSTR(expr)
+
+Test_Feature *current_feature = NULL;
+
+#define FEATURE_START__(NAME, NUMBER) \
+    { \
+        Test_Feature *feature = mem_alloc(sizeof(Test_Feature)); \
+        feature->next = current_feature; \
+        current_feature = feature; \
+        current_feature->name = NAME; \
+        current_feature->test_head = NULL; \
+        current_feature->success_count = 0; \
+        current_feature->test_count = 0; \
+    }
+
+#define FEATURE_START_(NAME, NUMBER) \
+    FEATURE_START__(NAME, NUMBER)    
+
+#define FEATURE_START(NAME) \
+    FEATURE_START_(NAME, __COUNTER__)
+
+#define FEATURE_END()
+
+#define TEST__(EXPR, ERROR_FMT, NUMBER, ...) \
+    { \
+        Test *test = mem_alloc(sizeof(Test)); \
+        test->next = current_feature->test_head; \
+        current_feature->test_head = test; \
+        current_feature->test_head->condition_str = STR(EXPR); \
+        current_feature->test_head->is_succeeded = EXPR; \
+        if(current_feature->test_head->is_succeeded) {\
+            current_feature->success_count += 1; \
+        }\
+        else { \
+            current_feature->test_head->error_msg = mem_alloc(256); \
+            sprint_fmt(current_feature->test_head->error_msg, ERROR_FMT, __VA_ARGS__); \
+        }\
+        current_feature->test_count += 1; \
+    }
+
+#define TEST_(EXPR, ERROR_MSG, NUMBER, ...) \
+    TEST__(EXPR, ERROR_MSG, NUMBER, __VA_ARGS__)
+
+#define TEST(EXPR, ERROR_MSG, ...) \
+    TEST_(EXPR, ERROR_MSG, __COUNTER__, __VA_ARGS__)
+
+#define TESTS_PRINT_RESULT() \
+    print_test_results(current_feature)
+
+int main(int argc, char **argv) {
+    FEATURE_START("limits.h");
+    {
+        // Check existing of macro definitions
+        #ifdef BOOL_WIDTH
+            TEST(BOOL_WIDTH == 8*sizeof(bool), "BOOL_WIDTH isn't correlated with sizeof(bool)");
+        #else
+            TEST(false, "The macro BOOL_WIDTH wasn't defined");
+        #endif
+        #ifdef CHAR_WIDTH
+            TEST(CHAR_WIDTH == 8, "CHAR_WIDTH isn't 8");
+        #else
+            TEST(false, "The macro CHAR_WIDTH wasn't defined");
+        #endif
+        #ifdef CHAR_BIT
+            TEST(CHAR_BIT == 8, "CHAR_BIT isn't 8");
+        #else
+            TEST(false, "The macro CHAR_BIT wasn't defined");
+        #endif
+        #ifdef CHAR_MIN
+            TEST(CHAR_MIN == -128, "CHAR_MIN isn't -128");
+        #else
+            TEST(false, "The macro CHAR_MIN wasn't defined");
+        #endif
+        #ifdef CHAR_MAX
+            TEST(CHAR_MAX == 127, "CHAR_MAX isn't 127");
+        #else
+            TEST(false, "The macro CHAR_MAX wasn't defined");
+        #endif
+        #ifdef MB_LEN_MAX
+            TEST(true, "");
+        #else
+            TEST(false, "The macro MB_LEN_MAX wasn't defined");
+        #endif
+        
+        #ifdef SCHAR_WIDTH
+            TEST(SCHAR_WIDTH == 8, "SCHAR_WIDTH isn't 8");
+        #else
+            TEST(false, "The macro SCHAR_WIDTH wasn't defined");
+        #endif
+        #ifdef SHRT_WIDTH
+            TEST(SHRT_WIDTH == 16, "SHRT_WIDTH isn't 16");
+        #else
+            TEST(false, "The macro SHRT_WIDTH wasn't defined");
+        #endif
+        #ifdef INT_WIDTH
+            TEST(INT_WIDTH == 32, "INT_WIDTH isn't 32");
+        #else
+            TEST(false, "The macro INT_WIDTH wasn't defined");
+        #endif
+        #ifdef LONG_WIDTH
+            TEST(LONG_WIDTH == 32, "LONG_WIDTH isn't 32");
+        #else
+            TEST(false, "The macro LONG_WIDTH wasn't defined");
+        #endif
+        #ifdef LLONG_WIDTH
+            TEST(LLONG_WIDTH == 64, "LLONG_WIDTH isn't 64");
+        #else
+            TEST(false, "The macro LLONG_WIDTH wasn't defined");
+        #endif
+        
+        #ifdef SCHAR_MIN
+            TEST(SCHAR_MIN == -128, "SCHAR_MIN isn't -128");
+        #else
+            TEST(false, "The macro SCHAR_MIN wasn't defined");
+        #endif
+        #ifdef SHRT_MIN
+            TEST(SHRT_MIN == -0x8000, "SHRT_MIN isn't -0x8000");
+        #else
+            TEST(false, "The macro SHRT_MIN wasn't defined");
+        #endif
+        #ifdef INT_MIN
+            TEST(INT_MIN == -0x80000000, "INT_MIN isn't -0x80000000");
+        #else
+            TEST(false, "The macro INT_MIN wasn't defined");
+        #endif
+        #ifdef LONG_MIN
+            TEST(LONG_MIN == -0x80000000l, "LONG_MIN isn't -0x80000000");
+        #else
+            TEST(false, "The macro LONG_MIN wasn't defined");
+        #endif
+        #ifdef LLONG_MIN
+            TEST(LLONG_MIN == -0x8000000000000000ll, "LLONG_MIN isn't -0x8000000000000000");
+        #else
+            TEST(false, "The macro LLONG_MIN wasn't defined");
+        #endif
+        
+        #ifdef SCHAR_MAX
+            TEST(SCHAR_MAX == 127, "SCHAR_MAX isn't 127");
+        #else
+            TEST(false, "The macro SCHAR_MAX wasn't defined");
+        #endif
+        #ifdef SHRT_MAX
+            TEST(SHRT_MAX == 0x7fff, "SHRT_MAX isn't 0x7fff");
+        #else
+            TEST(false, "The macro SHRT_MAX wasn't defined");
+        #endif
+        #ifdef INT_MAX
+            TEST(INT_MAX == 0x7fffffff, "INT_MAX isn't 0x7fffffff");
+        #else
+            TEST(false, "The macro INT_MAX wasn't defined");
+        #endif
+        #ifdef LONG_MAX
+            TEST(LONG_MAX == 0x7fffffff, "LONG_MAX isn't 0x7fffffff");
+        #else
+            TEST(false, "The macro LONG_MAX wasn't defined");
+        #endif
+        #ifdef LLONG_MAX
+            TEST(LLONG_MAX == 0x7fffffffffffffffll, "LLONG_MAX isn't 0x7fffffffffffffff");
+        #else
+            TEST(false, "The macro LLONG_MAX wasn't defined");
+        #endif
+        
+        #ifdef UCHAR_WIDTH
+            TEST(UCHAR_WIDTH == 8, "UCHAR_WIDTH isn't 8");
+        #else
+            TEST(false, "The macro UCHAR_WIDTH wasn't defined");
+        #endif
+        #ifdef USHRT_WIDTH
+            TEST(USHRT_WIDTH == 16, "USHRT_WIDTH isn't 16");
+        #else
+            TEST(false, "The macro USHRT_WIDTH wasn't defined");
+        #endif
+        #ifdef UINT_WIDTH
+            TEST(UINT_WIDTH == 32, "UINT_WIDTH isn't 32");
+        #else
+            TEST(false, "The macro UINT_WIDTH wasn't defined");
+        #endif
+        #ifdef ULONG_WIDTH
+            TEST(ULONG_WIDTH == 32, "ULONG_WIDTH isn't 32");
+        #else
+            TEST(false, "The macro ULONG_WIDTH wasn't defined");
+        #endif
+        #ifdef ULLONG_WIDTH
+            TEST(ULLONG_WIDTH == 64, "ULLONG_WIDTH isn't 64");
+        #else
+            TEST(false, "The macro ULLONG_WIDTH wasn't defined");
+        #endif
+        
+        #ifdef UCHAR_MAX
+            TEST(UCHAR_MAX == 255, "UCHAR_MAX isn't 255");
+        #else
+            TEST(false, "The macro UCHAR_MAX wasn't defined");
+        #endif
+        #ifdef USHRT_MAX
+            TEST(USHRT_MAX == 0xffffu, "USHRT_MAX isn't 0xffff");
+        #else
+            TEST(false, "The macro USHRT_MAX wasn't defined");
+        #endif
+        #ifdef UINT_MAX
+            TEST(UINT_MAX == 0xffffffffu, "UINT_MAX isn't 0xffffffff");
+        #else
+            TEST(false, "The macro UINT_MAX wasn't defined");
+        #endif
+        #ifdef ULONG_MAX
+            TEST(ULONG_MAX == 0xffffffffu, "ULONG_MAX isn't 0xffffffff");
+        #else
+            TEST(false, "The macro ULONG_MAX wasn't defined");
+        #endif
+        #ifdef ULLONG_MAX
+            TEST(ULLONG_MAX == 0xffffffffffffffffull, "ULLONG_MAX isn't 0xffffffffffffffffull");
+        #else
+            TEST(false, "The macro ULLONG_MAX wasn't defined");
+        #endif
+            
+        #ifdef PTRDIFF_WIDTH
+            TEST(true, "");
+        #else
+            TEST(false, "The macro PTRDIFF_WIDTH isn't defined");
+        #endif
+        #ifdef PTRDIFF_MIN
+            TEST(true, "");
+        #else
+            TEST(false, "The macro PTRDIFF_MIN isn't defined");
+        #endif
+        #ifdef PTRDIFF_MAX
+            TEST(true, "");
+        #else
+            TEST(false, "The macro PTRDIFF_MAX isn't defined");
+        #endif
+        #ifdef SIZE_WIDTH
+            TEST(true, "");
+        #else
+            TEST(false, "The macro SIZE_WIDTH isn't defined");
+        #endif
+        #ifdef SIZE_MAX
+            TEST(true, "");
+        #else
+            TEST(false, "The macro SIZE_MAX isn't defined");
+        #endif
+        #ifdef SIG_ATOMIC_WIDTH
+            TEST(true, "");
+        #else
+            TEST(false, "The macro SIG_ATOMIC_WIDTH isn't defined");
+        #endif
+            #ifdef SIG_ATOMIC_MIN
+            TEST(true, "");
+        #else
+            TEST(false, "The macro SIG_ATOMIC_MIN isn't defined");
+        #endif
+            #ifdef SIG_ATOMIC_MAX
+            TEST(true, "");
+        #else
+            TEST(false, "The macro SIG_ATOMIC_MAX isn't defined");
+        #endif
+        #ifdef WINT_WIDTH
+            TEST(true, "");
+        #else
+            TEST(false, "The macro WINT_WIDTH isn't defined");
+        #endif
+            #ifdef WINT_MIN
+            TEST(true, "");
+        #else
+            TEST(false, "The macro WINT_MIN isn't defined");
+        #endif
+            #ifdef WINT_MAX
+            TEST(true, "");
+        #else
+            TEST(false, "The macro WINT_MAX isn't defined");
+        #endif
+        #ifdef WCHAR_WIDTH
+            TEST(true, "");
+        #else
+            TEST(false, "The macro WCHAR_WIDTH isn't defined");
+        #endif
+        #ifdef WCHAR_MIN
+            TEST(true, "");
+        #else
+            TEST(false, "WCHAR_MIN isn't defined");
+        #endif
+            #ifdef WCHAR_MAX
+            TEST(true, "");
+        #else
+            TEST(false, "WCHAR_MAX isn't defined");
+        #endif
+    }
+    FEATURE_END();
+
+    FEATURE_START("ctype.h");
+    {
+        // Test letters
+        for(int i = 0; i != 10; ++i) {
+            int letter = random_between('a', 'z');
+            TEST(isalpha(letter) != 0, "isalpha('%c') returned false", letter);
+            TEST(isdigit(letter) == 0, "isdigit('%c') returned true", letter);
+        }
+        // Test digits
+        for(int i = 0; i != 10; ++i) {
+            int digit = random_between('0', '9');
+            TEST(isalpha(digit) == 0, "isalpha('%c') returned true", digit);
+            TEST(isdigit(digit) != 0, "isdigit('%c') returned false", digit);
+        }
+    }
+    FEATURE_END();
+    
+    FEATURE_START("IO functions (stdio.h)");
+    {
+        static int numbers[10] = {0,1,2,3,4,5,6,7,8,9};
+        // fread/fwrite
+        {
+            FILE *file = fopen("test_folder/file", "wb");
+            TEST(file != NULL, "Created file is NULL");
+            int cnt_written = fwrite(numbers, sizeof(int), 10, file);
+            TEST(cnt_written == 10, "fwrite didn't write all 10 objects");
+            TEST(fclose(file) == 0, "fclose didn't close the file");
+            TEST(rename("test_folder/file", "test_folder/file2") == 0, "Rename returned 0");
+            file = fopen("test_folder/file2", "rb");
+            TEST(file != NULL, "Created file is NULL");
+            int read_numbers[10];
+            int cnt_read = fread(numbers, sizeof(int), 10, file);
+            TEST(cnt_read == 10, "fread didn't read 10 objects");
+            bool all_ok = true;
+            for(int i = 0; i != 10; ++i) {
+                if(read_numbers[i] != numbers[i]) {
+                    all_ok = false;
+                    break;
+                }
+            }
+            TEST(all_ok, "The elements read didn't match the elements written");
+            TEST(fclose(file) == 0, "fclose didn't close the file");
+            TEST(remove("test_folder/file2") == 0, "remove didn't remove the file");
+        }
+        // Seeking and stuff
+        {
+            FILE *file = fopen("test_folder/seek", "wb");
+            TEST(file != NULL, "Created file is NULL");
+            TEST(fwrite(numbers, sizeof(int), 10, file) == 10, "fwrite didn't write all 10 objects");
+            TEST(fseek(file, 4*sizeof(int), SEEK_SET) == 0, "fseek couldn't seek to offset 4");
+            int num;
+            TEST(fread(&num, sizeof(int), 1, file) == 1, "fread didn't read the int");
+            TEST(num == 4, "Wrong value read at offset 4");
+            TEST(fseek(file, -4, SEEK_END) == 0, "fseek coudn't seek to the end");
+            TEST(fread(&num, sizeof(int), 1, file) == 1, "fread didn't read the int");
+            TEST(num == 9, "Wrong number read");
+            TEST(fclose(file) == 0, "fclose didn't close the file");
+        }
+        // Getchar, ungetchar
+        {
+            char str[] = "Hello, world!";
+            FILE *file = fopen("test_folder/getc", "wb");
+            TEST(file != NULL, "Created file is NULL");
+            TEST(fputs(str, file) >= 0, "fputs failed");
+            TEST(fputc('!', file) == '!', "fputc failed");
+            TEST(fflush(file) == 0, "fflush failed");
+            fclose(file);
+            file = freopen("test_folder/getc", "rb", file);
+            TEST(file != NULL, "Reopened file is NULL");
+            TEST(fgets(str, sizeof str, file) == str, "fgets failed");
+            TEST(fgetc(file) == '!', "fgetc read the wrong thing");
+            TEST(fclose(file) == 0, "fclose failed");
+        }
+    }
+
+    TESTS_PRINT_RESULT();
+    return 0;
+}
diff --git a/todo b/todo
index 07ead5e..2cc7243 100644
--- a/todo
+++ b/todo
@@ -53,6 +53,9 @@ stdio.h:
 *   tmpnam_s
 *   Printing 8.98846567431157854073e+307
 *   Printing negative zero
+*   Add functions for testing a file path, creating directories
+*   Fix the bug where if a file wasn't closed the thing crashes when
+    trying to flush the buffer
 
 stdlib.h:
 *   Strtod base 16 must be correctly rounded