diff --git a/aux_lib.c b/aux_lib.c
index 469bd42..631d9d2 100644
--- a/aux_lib.c
+++ b/aux_lib.c
@@ -1,4 +1,5 @@
 #include "aux_lib.h"
+#include <stddef.h>
 
 /*
  * Функция возвращает n-ный элемент последовательности фибоначи
@@ -6,8 +7,22 @@
 int
 fibonacci(int nitem)
 {
-	//YOUR_CODE
-	return 42;
+	if (nitem < 0)
+		return -1;
+
+	if (nitem == 0)
+		return 0;
+	if (nitem == 1)
+		return 1;
+
+	int a = 0, b = 1;
+	for (int i = 2; i <= nitem; i++) {
+		int next = a + b;
+		a = b;
+		b = next;
+	}
+
+	return b;
 }
 
 /*
@@ -17,6 +32,12 @@ fibonacci(int nitem)
 bool
 sum_is_odd(int *arr, int arrsz)
 {
-	//YOUR_CODE
-	return false;
+	if (arr == NULL || arrsz <= 0)
+		return false;
+
+	long sum = 0;
+	for (int i = 0; i < arrsz; i++) {
+		sum += arr[i];
+	}
+	return (sum % 2 != 0);
 }
diff --git a/aux_test.c b/aux_test.c
index 0de7fbf..927f189 100644
--- a/aux_test.c
+++ b/aux_test.c
@@ -2,14 +2,102 @@
 #include "munit.h"
 #include "aux_lib.h"
 
-static const MunitSuite test_suite = {
-	//FILL ME
+/****************** TEST fibonacci()*********************/
+static MunitResult
+test_fibonacci_basic(const MunitParameter params[], void *data)
+{
+    (void) params;
+    (void) data;
+
+    munit_assert_int(fibonacci(0), ==, 0);
+    munit_assert_int(fibonacci(1), ==, 1);
+    munit_assert_int(fibonacci(2), ==, 1);
+    munit_assert_int(fibonacci(3), ==, 2);
+    munit_assert_int(fibonacci(4), ==, 3);
+    munit_assert_int(fibonacci(5), ==, 5);
+    munit_assert_int(fibonacci(10), ==, 55);
+
+    return MUNIT_OK;
+}
+
+static MunitResult
+test_fibonacci_negative(const MunitParameter params[], void *data)
+{
+    (void) params;
+    (void) data;
+
+    munit_assert_int(fibonacci(-1), ==, -1);
+    munit_assert_int(fibonacci(-5), ==, -1);
+
+    return MUNIT_OK;
+}
+
+/************* TEST sum_is_odd() *************/
+
+static MunitResult
+test_sum_is_odd_basic(const MunitParameter params[], void *data)
+{
+    (void) params;
+    (void) data;
+
+    int a1[] = {1};
+    munit_assert_true(sum_is_odd(a1, 1) == true);
+
+    int a2[] = {2};
+    munit_assert_true(sum_is_odd(a2, 1) == false);
+
+    int a3[] = {1, 2, 3}; // сумма = 6
+    munit_assert_false(sum_is_odd(a3, 3));
+
+    int a4[] = {1, 2, 4}; // сумма = 7
+    munit_assert_true(sum_is_odd(a4, 3));
+
+    return MUNIT_OK;
+}
+
+static MunitResult
+test_sum_is_odd_edge_cases(const MunitParameter params[], void *data)
+{
+    (void) params;
+    (void) data;
+
+    munit_assert_false(sum_is_odd(NULL, 10));
+    munit_assert_false(sum_is_odd(NULL, -1));
+
+    int arr[] = {1};
+    munit_assert_false(sum_is_odd(arr, 0));
+
+    return MUNIT_OK;
+}
+
+/*************** suit ***************/
+
+#define TEST_ITEM(func) { #func, func, NULL, NULL, MUNIT_TEST_OPTION_NONE, NULL }
+
+static MunitTest test_suite_tests[] = {
+    TEST_ITEM(test_fibonacci_basic),
+    TEST_ITEM(test_fibonacci_negative),
+    TEST_ITEM(test_sum_is_odd_basic),
+    TEST_ITEM(test_sum_is_odd_edge_cases),
+
+    { NULL, NULL, NULL, NULL, MUNIT_TEST_OPTION_NONE, NULL }
 };
 
+static const MunitSuite test_suite = {
+    (char *) "",
+    test_suite_tests,
+    NULL,
+    1,
+    MUNIT_SUITE_OPTION_NONE
+};
+
+/********************** MAIN **********************/
+
 int
 main(int argc, const char *argv[])
 {
-	munit_suite_main(&test_suite, (void *) "string library test", argc, (char * const*) argv);
-	return 0;
+    return munit_suite_main(&test_suite,
+                            (void *) "aux library test",
+                            argc,
+                            (char* const*) argv);
 }
-