diff --git a/CMakeLists.txt b/CMakeLists.txt
index 7b179b1..bd6b4d2 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -14,7 +14,8 @@ else()
     target_compile_options(cosms-core PRIVATE -Wall -Wextra -pedantic)
 endif()
 
-add_executable(cosms-core-test ${PROJECT_SOURCE_DIR}/tests/main.c)
+file(GLOB_RECURSE SRC_TEST_FILES "${PROJECT_SOURCE_DIR}/tests/*.c")
+add_executable(cosms-core-test ${SRC_TEST_FILES})
 
 target_include_directories(cosms-core-test PRIVATE ${PROJECT_SOURCE_DIR}/tests)
 target_link_libraries(cosms-core-test cosms-core)
diff --git a/tests/data/large-file.txt b/tests/data/large-file.txt
new file mode 100644
index 0000000..d4c5011
Binary files /dev/null and b/tests/data/large-file.txt differ
diff --git a/tests/data/small-file.txt b/tests/data/small-file.txt
new file mode 100644
index 0000000..b45ef6f
--- /dev/null
+++ b/tests/data/small-file.txt
@@ -0,0 +1 @@
+Hello, World!
\ No newline at end of file
diff --git a/tests/main.c b/tests/main.c
index f6b1706..b348f4f 100644
--- a/tests/main.c
+++ b/tests/main.c
@@ -1,22 +1,6 @@
-#include <cosms-core/file.h>
-
-#include <stdio.h>
+#include "unit/unit.h"
 
 int main(void) {
-    unsigned long long buffer_size;
-    char *buffer;
-	CosmsFileError error = cosms_core_file_read("test.txt", &buffer, &buffer_size);
-    if (error != COSMS_FILE_OK) {
-        fprintf(stderr, "error(%d): %s\n", error, cosms_core_file_error_string(error));
-    } else {
-        printf("file read with content:\n%s\n", buffer);
-    }
-
-    char *temp_buffer = "Hello, World!";
-    error = cosms_core_file_write("write-file.txt", temp_buffer, 13, true);
-    if (error != COSMS_FILE_OK) {
-        fprintf(stderr, "error(%d): %s\n", error, cosms_core_file_error_string(error));
-    }
-
+    cosms_file_read_test();
 	return 0;
 }
diff --git a/tests/test.h b/tests/test.h
new file mode 100644
index 0000000..a1a8ca1
--- /dev/null
+++ b/tests/test.h
@@ -0,0 +1,12 @@
+#ifndef COSMS_TEST
+#define COSMS_TEST
+
+#include <stdio.h>
+
+#define COSMS_TEST_HEADER(test_module_name) printf("----------------------------------------\n%s\n----------------------------------------\n", test_module_name);
+
+#define COSMS_TEST_START(test_name) printf("[*] running test %s...\n", test_name)
+#define COSMS_TEST_SUCCESS(test_name) printf("[+] test %s completed successfully!\n", test_name);
+#define COSMS_TEST_FAIL(test_name, error) printf("[-] test %s failed with error: %s\n", test_name, error)
+
+#endif
\ No newline at end of file
diff --git a/tests/unit/file.c b/tests/unit/file.c
new file mode 100644
index 0000000..1052bb1
--- /dev/null
+++ b/tests/unit/file.c
@@ -0,0 +1,75 @@
+#include "file.h"
+#include "../test.h"
+//#include <cosms-core/file.h>
+#include "../../include/cosms-core/file.h"
+
+#include <string.h>
+#include <stdlib.h>
+
+void cosms_file_read_test() {
+    COSMS_TEST_HEADER("file read");
+
+    const char *current_test_name = "reading small file";
+    COSMS_TEST_START(current_test_name);
+
+    unsigned long long file_size;
+    char *file_buffer;
+    CosmsFileError error = cosms_core_file_read("tests/data/small-file.txt", &file_buffer, &file_size);
+    if (error != COSMS_FILE_OK) {
+        COSMS_TEST_FAIL(current_test_name, cosms_core_file_error_string(error));
+    } else {
+        const char *expected_result = "Hello, World!";
+        if (file_size != strlen(expected_result) || strcmp(expected_result, file_buffer)) {
+            COSMS_TEST_FAIL(current_test_name, "result does not match expected result");
+        } else {
+            COSMS_TEST_SUCCESS(current_test_name);
+        }
+    }
+
+    free(file_buffer);
+
+    current_test_name = "reading large file";
+    COSMS_TEST_START(current_test_name);
+
+    file_size = 0;
+    file_buffer = NULL;
+    error = cosms_core_file_read("tests/data/large-file.txt", &file_buffer, &file_size);
+    if (error != COSMS_FILE_OK) {
+        COSMS_TEST_FAIL(current_test_name, cosms_core_file_error_string(error));
+    } else {
+        unsigned long long expected_size = 5242880000ULL;
+        char *expected_result = (char*)malloc((expected_size + 1) * sizeof(char));
+        if (!expected_result) {
+            printf("[-] failed to allocate memory for test aborting file read tests...\n");
+            free(file_buffer);
+            return;
+        }
+
+        memset(expected_result, 'a', expected_size);
+        expected_result[expected_size] = '\0';
+
+        if (file_size != expected_size || strcmp(expected_result, file_buffer)) {
+            COSMS_TEST_FAIL(current_test_name, "result does not match expected result");
+        } else {
+            COSMS_TEST_SUCCESS(current_test_name);
+        }
+
+        free(expected_result);
+    }
+
+    free(file_buffer);
+
+    current_test_name = "reading non existing file";
+    COSMS_TEST_START(current_test_name);
+
+    file_size = 0;
+    file_buffer = NULL;
+    error = cosms_core_file_read("non-existing-file.cosms", &file_buffer, &file_size);
+    if (error == COSMS_FILE_NOT_FOUND) {
+        COSMS_TEST_SUCCESS(current_test_name);
+    } else {
+        COSMS_TEST_FAIL(current_test_name, cosms_core_file_error_string(error));
+    }
+
+    free(file_buffer);
+}
\ No newline at end of file
diff --git a/tests/unit/file.h b/tests/unit/file.h
new file mode 100644
index 0000000..da53018
--- /dev/null
+++ b/tests/unit/file.h
@@ -0,0 +1,8 @@
+#ifndef COSMS_FILE_TEST
+#define COSMS_FILE_TEST
+
+#include <stdbool.h>
+
+void cosms_file_read_test();
+
+#endif
\ No newline at end of file
diff --git a/tests/unit/unit.h b/tests/unit/unit.h
new file mode 100644
index 0000000..153c7cc
--- /dev/null
+++ b/tests/unit/unit.h
@@ -0,0 +1,6 @@
+#ifndef COSMS_UNIT
+#define COSMS_UNIT
+
+#include "file.h"
+
+#endif
\ No newline at end of file