added first unit test

unit-tests/README.md

@@ -0,0 +1,10 @@
+For unit test `test_parse_ics.c`.
+
+compilation command:
+```
+gcc -Wall test_parse_ics.c ../src/parse_ics.c ../src/string_handling.c ../src/list_handling.c ../src/date_time_handling.c ../src/read_until_string.c ../src/read_until_nl.c
+```
+
+```
+./a.out
+```

unit-tests/test_parse_ics.c

@@ -0,0 +1,12 @@
+#include "../src/list_handling.h"
+#include "../src/parse_ics.h"
+#include <stdio.h>
+
+int main() {
+	// initialize empty list
+	struct event *head = NULL;
+
+	parse_ics_file("../tests/calendar.ics", &head);
+
+	print_list(head);
+}