updated readme

only test one function per unit test file.

.gitignore

@@ -1,4 +1,5 @@
 icscli
 .gitconfig
 *.o
+*.out
 tags

README.md

@@ -1,14 +1,23 @@
-Show upcoming events of an .ics file.\
+## ics_cli
+
+#### use case
+
+- show upcoming events of an .ics file
+- insert events in your calendar
 
 
 #### installation
 
 ```
-make
+cd src/builddir
 ``` 
 
 ```
-sudo make install
+meson compile
+```
+
+```
+meson install
 ```
 
 #### usage
@@ -31,9 +40,18 @@ icscli -h
 #### uninstall
 
 ```
-sudo make uninstall
+sudo rm -f /usr/local/bin/icscli
 ```
 
+#### git-hooks for ctags pre-commit
+
+The developer has to actively enable git hooks:
+```
+git config --local core.hooksPath git-hooks
+```
+This will run `ctags` on every commit.
+
 #### TODO
 
-- more tests
+- improve and automate unit testing
+- add cli argument that will not show ongoing events, only upcoming events

git-hooks/pre-commit

@@ -0,0 +1,29 @@
+#!/bin/bash
+
+# make a dir called git-hooks in the top level of your repo
+# put the following line in a Readme.md:
+# git config --local core.hooksPath git-hooks
+# the user has to actively enable git hooks
+# this script has to be named "pre-commit" and should be placed
+# in the core.hooksPath
+
+if type ctags &>> /dev/null; then
+        ctags_installed=1
+else
+        ctags_installed=0
+fi
+
+if ! (( ${ctags_installed} )); then
+	printf "Ctags is not installed! Git hooks are enabled and can only be executed if it is installed.\n"
+	printf "Commit was aborted.\n"
+	exit 1
+fi
+
+if ! ctags -R src/.; then
+	printf "Ctags failed.\n\n"
+	exit 1
+else
+	printf "Ctags was successfully executed.\n"
+fi
+
+exit 0

src/Makefile

@@ -1,42 +0,0 @@
-CC = gcc
-CFLAGS = -Wall -g -O0
-LDFLAGS = -luuid
-
-# List of all source files (assuming they're all in the same directory)
-SRC_FILES = $(wildcard *.c)
-
-# Generate a list of object files by replacing the .c extension with .o
-OBJ_FILES = $(SRC_FILES:.c=.o)
-
-EXECUTABLE = "icscli"
-
-# linking
-$(EXECUTABLE): $(OBJ_FILES)
-	gcc $(CFLAGS) $(OBJ_FILES) -o $(EXECUTABLE) $(LDFLAGS)
-
-main.o: main.c
-	$(CC) $(CFLAGS) -c $<
-
-# use implicit rule to compile C source files to object files
-%.o: %.c %.h
-	$(CC) $(CFLAGS) -c $<
-
-.PHONY:install
-install: $(EXECUTABLE)
-	cp $(EXECUTABLE) /usr/local/bin/$(EXECUTABLE)
-
-.PHONY:clean
-clean:
-	-rm -f $(EXECUTABLE) *.o
-
-.PHONY:uninstall
-uninstall:
-	-rm /usr/local/bin/$(EXECUTABLE)
-
-.PHONY:test
-test:
-	./$(EXECUTABLE)
-	@echo
-	./$(EXECUTABLE) -h
-	@echo
-	./$(EXECUTABLE) -f ../tests/calendar.ics

src/date_time_handling.c

@@ -5,94 +5,135 @@
 #include <string.h>
 #include <time.h>
 #include <unistd.h>
+#include <assert.h>
 
 // buffer needs to contain a string with a strlen of 15 (format: "xxxxxxxxTxxxxxx")
 // or a strlen of 16 (format: "YYYYmmddTHHMMSSZ")
-void get_date(char buffer[]) {
+void get_date (char buffer[]) {
 	// add 1 because strlen does not include the null character
-	size_t buffer_size = strlen(buffer) + 1;
-	time_t my_unix_ts = time(NULL);
-	struct tm* my_tm_local = localtime(&my_unix_ts);
-	if (strlen(buffer) == 15) {
-		strftime(buffer, buffer_size, "%Y%m%dT%H%M%S", my_tm_local);
-	} else if (strlen(buffer) == 16) {
-		strftime(buffer, buffer_size, "%Y%m%dT%H%M%SZ", my_tm_local);
+	size_t buffer_size = strlen (buffer) + 1;
+	time_t my_unix_ts = time (NULL);
+	struct tm* my_tm_local = localtime (&my_unix_ts);
+	if (strlen (buffer) == 15) {
+		strftime (buffer, buffer_size, "%Y%m%dT%H%M%S", my_tm_local);
+	}
+	else if (strlen (buffer) == 16) {
+		strftime (buffer, buffer_size, "%Y%m%dT%H%M%SZ", my_tm_local);
 	}
 }
 
 // 20230823T194138 -> 2023-08-23 19:41:38
-void pretty_print_date_time(char date_time[]) {
-	char *date = strtok(date_time, "T");
-	char *time = strtok(NULL, "T");
-	if (date == NULL) {
-		printf ("\nError: date points to NULL!\n");
-		exit(1);
+// 20230823T194138Z -> 2023-08-23 19:41:38
+// 20241209 -> 2024-12-09
+// caller has to free() the returned char array
+char* pretty_date_time (char date_time[]) {
+	// need one more char in the char pointer for null-termination
+	int pdt_len = 20;
+	if (!strchr (date_time, 'T')) {
+		pdt_len = 11;
 	}
-	printf ("%c%c%c%c-", date[0], date[1], date[2], date[3]);
-	printf ("%c%c-", date[4], date[5]);
-	printf ("%c%c", date[6], date[7]);
-	
-	if (time != NULL) {
-		printf (" %c%c:", time[0], time[1]);
-		printf ("%c%c:", time[2], time[3]);
-		printf ("%c%c", time[4], time[5]);
+
+	char* pretty_dt = malloc (pdt_len);
+	memset(pretty_dt, '\0', pdt_len);
+	int dt_counter = 0;
+
+	if (!strcmp(date_time, "")) {
+		return pretty_dt;
 	}
+
+	for (int i = 0; i < (pdt_len-1); i++) {
+		if (i == 4 || i == 7) {
+			pretty_dt[i] = '-';
+			continue;
+		}
+		if (i == 13 || i == 16) {
+			pretty_dt[i] = ':';
+			continue;
+		}
+
+		if (date_time[dt_counter] == 'T') {
+			pretty_dt[i] = ' ';
+		} else {
+			pretty_dt[i] = date_time[dt_counter];
+		}
+		dt_counter++;
+	}
+
+	// null-terminate string
+	pretty_dt[strlen(pretty_dt)] = '\0';
+
+	return pretty_dt;
 }
 
-void marshall_date_time(char date_time[]) {
-	char transformed_string[strlen(date_time)];
+void pretty_print_date_time (char date_time[]) {
+	char* pdt = pretty_date_time(date_time);
+
+	printf("%s", pdt);
+
+	free(pdt);
+}
+
+void marshall_date_time (char date_time[]) {
+	char transformed_string[strlen (date_time)];
 	int j = 0;
-	remove_nl_and_cr(date_time);
-	for (int i = 0; i<=strlen(date_time); i++) {
+	remove_nl_and_cr (date_time);
+	for (int i = 0; i <= strlen (date_time); i++) {
 		if (date_time[i] != ':' && date_time[i] != '-') {
 			if (date_time[i] == ' ') {
 				transformed_string[j] = 'T';
-			} else {
+			}
+			else {
 				transformed_string[j] = date_time[i];
 			}
-			
+
 			j++;
 		}
-	
+
 	}
-	memset(date_time, '\0', strlen(date_time));
-	strcpy(date_time, transformed_string);
+	memset (date_time, '\0', strlen (date_time));
+	strcpy (date_time, transformed_string);
 }
 
-void print_end_date(char end_date[], char start_date[]) {
-	time_t start_uts = transform_date_to_unix_ts(start_date);
-	time_t end_uts = transform_date_to_unix_ts(end_date);
-	double time_difference = difftime(end_uts, start_uts);
+void print_end_date (char end_date[], char start_date[]) {
+	time_t start_uts = transform_date_to_unix_ts (start_date);
+	time_t end_uts = transform_date_to_unix_ts (end_date);
+	double time_difference = difftime (end_uts, start_uts);
 
 	// end_date is all day event
-	if (strlen(end_date) == 8) {
+	if (strlen (end_date) == 8) {
 		if (time_difference == 86400) {
 			return;
-		} else {
+		}
+		else {
 			printf (" - ");
 			end_uts -= 86400;
-			char *end_date_minus_one = transform_unix_ts_to_date(end_uts);
-			pretty_print_date_time(end_date_minus_one);
-			free(end_date_minus_one);
+			char* end_date_minus_one =
+				transform_unix_ts_to_date (end_uts);
+			pretty_print_date_time (end_date_minus_one);
+			free (end_date_minus_one);
 			return;
 		}
-	} else {
+	}
+	else {
 		// end_date is not an all day event
 
-		char *end_date_chunk = strtok(end_date, "T");
-		char *end_time_chunk = strtok(NULL, "T");
-		char *start_date_chunk = strtok(start_date, "T");
+		char* end_date_chunk = strtok (end_date, "T");
+		char* end_time_chunk = strtok (NULL, "T");
+		char* start_date_chunk = strtok (start_date, "T");
 
 		printf (" - ");
 
 		// only print the end date if it is not the same as the start date
-		if (strcmp(start_date_chunk, end_date_chunk) != 0) {
-			printf("%c%c%c%c-", end_date_chunk[0], end_date_chunk[1], \
-			end_date_chunk[2], end_date_chunk[3]);
-			printf("%c%c-", end_date_chunk[4], end_date_chunk[5]);
-			printf("%c%c ", end_date_chunk[6], end_date_chunk[7]);
+		if (strcmp (start_date_chunk, end_date_chunk) != 0) {
+			printf ("%c%c%c%c-", end_date_chunk[0],
+				end_date_chunk[1], end_date_chunk[2],
+				end_date_chunk[3]);
+			printf ("%c%c-", end_date_chunk[4],
+				end_date_chunk[5]);
+			printf ("%c%c ", end_date_chunk[6],
+				end_date_chunk[7]);
 		}
-		
+
 		printf ("%c%c:", end_time_chunk[0], end_time_chunk[1]);
 		printf ("%c%c:", end_time_chunk[2], end_time_chunk[3]);
 		printf ("%c%c", end_time_chunk[4], end_time_chunk[5]);
@@ -100,40 +141,41 @@ void print_end_date(char end_date[], char start_date[]) {
 }
 
 // YYYYmmdd -> unix timestamp
-time_t transform_date_to_unix_ts(char date_str[]) {
+time_t transform_date_to_unix_ts (char date_str[]) {
 	time_t unix_stamp = 0;
-	int date_only = atoi(date_str);
-	struct tm my_tm = {0};
+	int date_only = atoi (date_str);
+	struct tm my_tm = { 0 };
 	my_tm.tm_year = date_only / 10000 - 1900;
 	my_tm.tm_mon = (date_only % 10000) / 100 - 1;
 	my_tm.tm_mday = date_only % 100;
 
-	unix_stamp = mktime(&my_tm);
+	unix_stamp = mktime (&my_tm);
 
 	return unix_stamp;
 }
 
 // unix timestamp -> YYYYmmdd
 // make sure to free the returned buffer
-char *transform_unix_ts_to_date(time_t unix_ts) {
-	char *date_buffer = malloc(9);
-	struct tm *my_tm;
-	my_tm = localtime(&unix_ts);
-	strftime(date_buffer, 9, "%Y%m%d", my_tm);
+char* transform_unix_ts_to_date (time_t unix_ts) {
+	char* date_buffer = malloc (9);
+	struct tm* my_tm;
+	my_tm = localtime (&unix_ts);
+	strftime (date_buffer, 9, "%Y%m%d", my_tm);
 
 	return date_buffer;
 }
 
-char *get_tz() {
-	char *timezone_path = malloc(256);
-	ssize_t bytes_read = readlink("/etc/localtime", timezone_path, 255);
+char* get_tz () {
+	char* timezone_path = malloc (256);
+	ssize_t bytes_read = readlink ("/etc/localtime", timezone_path, 255);
 
 	if (bytes_read != -1) {
 		// Null-terminate the string
-    	timezone_path[bytes_read] = '\0';
-	} else {
-		perror("readlink");
-		exit(1);
+		timezone_path[bytes_read] = '\0';
+	}
+	else {
+		perror ("readlink");
+		exit (1);
 	}
 
 	return timezone_path;

src/date_time_handling.h

@@ -1,8 +1,11 @@
+#pragma once
+
 #include <time.h>
 #include <string.h>
 
 void get_date(char buffer[]);
 char *get_tz();
+char* pretty_date_time(char date_time[]);
 void pretty_print_date_time(char date_time[]);
 void marshall_date_time(char date_time[]);
 void print_end_date(char end_date[], char start_date[]);

src/list_handling.c

@@ -46,10 +46,12 @@ void free_list(struct event *head)
     }
 }
 
-void print_upcoming(struct event *head, char current_start_date[], int show_all_events) {
+// print_upcoming() also prints ongoing events
+// because you usually also want to see those
+void print_upcoming(struct event *head, char current_date[], int show_all_events) {
 	int i = 0;
 	while (head != NULL) {
-		if (strcmp(head->start_date, current_start_date) >= 0) {
+		if (strcmp(head->end_date, current_date) >= 0) {
 			pretty_print_date_time(head->start_date);
 			print_end_date(head->end_date, head->start_date);
 			printf("\nSUMMARY: %s\n", head->summary);

src/main.c

@@ -2,15 +2,7 @@
 #include "parse_ics.h"
 #include "cli_arg_parsing.h"
 #include "date_time_handling.h"
-#include "string_handling.h"
-#include "read_until_nl.h"
-#include "read_until_string.h"
-#include "seek_string_a.h"
 #include <stdio.h>
-#include <stdlib.h>
-#include <fcntl.h>
-#include <string.h>
-#include <limits.h>
 
 int main(int argc, char **argv) {
 	char *ics_path = "";
@@ -18,33 +10,16 @@ int main(int argc, char **argv) {
 
 	get_cli_args(argc, argv, &ics_path, &show_all_events);
 
-	char my_event[8192] = "";
-	char unfolded_event[8192] = "";
-
-	int myfd = open(ics_path, O_RDONLY);
-	if (myfd == -1) {
-		perror ("Error opening file");
-		return 1;
-	}
-
-	// initialize linked list
-	struct event *head = NULL;
-
 	static char current_date[] = "xxxxxxxxTxxxxxx";
 	get_date(current_date);
 	printf ("Current date and time: ");
 	pretty_print_date_time(current_date);
 	printf ("\n\n");
 
-	while(read_until_nl(myfd, my_event)) {
-		if (strncmp(my_event, "BEGIN:VEVENT", 12) == 0) {
-			memset(my_event, '\0', sizeof(my_event));
-			read_until_string(myfd, my_event, "END:VEVENT");
-			unfolding_string(my_event, unfolded_event);
-			parse_event(unfolded_event, &head);
-		}
-		memset(my_event, '\0', sizeof(my_event));
-	}
+	// initialize linked list
+	struct event *head = NULL;
+
+	parse_ics_file(ics_path, &head);
 
 	print_upcoming(head, current_date, show_all_events);
 

src/meson.build

@@ -0,0 +1,5 @@
+project('ics_cli', 'c')
+
+executable('icscli', 'main.c', 'cli_arg_parsing.c', 'date_time_handling.c', 'insert_event.c', \
+'list_handling.c', 'parse_ics.c', 'read_until_nl.c', 'read_until_string.c', 'seek_string_a.c', \
+'string_handling.c', link_args : '-luuid', install: true, install_dir: '/usr/local/bin')

src/parse_ics.c

@@ -1,11 +1,15 @@
 #include "list_handling.h"
 #include "parse_ics.h"
+#include "read_until_nl.h"
+#include "read_until_string.h"
 #include "string_handling.h"
-#include <stdlib.h>
-#include <string.h>
 #include <assert.h>
 #include <ctype.h>
+#include <fcntl.h>
 #include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
 
 void parse_event(char event_string[], struct event **head) {
 	char *start_date = strstr(event_string, "\nDTSTART");
@@ -67,3 +71,32 @@ void unfolding_string(char *folded_string, char *unfolded_string) {
 		}
 	}
 }
+
+/* this function takes the head of an empty initialized event list
+ * and the path to the ics file
+ * it will "fill" the list
+*/
+void parse_ics_file(char *file_path, struct event **head) {
+	char my_event[8192] = "";
+	char unfolded_event[8192] = "";
+
+	int myfd = open(file_path, O_RDONLY);
+	if (myfd == -1) {
+		perror ("Error opening file");
+		exit(1);
+	}
+
+	while(read_until_nl(myfd, my_event)) {
+		if (strncmp(my_event, "BEGIN:VEVENT", 12) == 0) {
+			// include the BEGIN:EVENT to not loose the new line of first field
+			lseek(myfd, -1, SEEK_CUR);
+			memset(my_event, '\0', sizeof(my_event));
+			read_until_string(myfd, my_event, "END:VEVENT");
+			unfolding_string(my_event, unfolded_event);
+			parse_event(unfolded_event, head);
+		}
+		memset(my_event, '\0', sizeof(my_event));
+	}
+
+	close(myfd);
+}

src/parse_ics.h

@@ -2,3 +2,4 @@
 
 void parse_event(char event_string[], struct event **head);
 void unfolding_string(char* folded_string, char* unfolded_string);
+void parse_ics_file(char *file_path, struct event **head);

tests/calendar.ics

@@ -301,9 +301,9 @@ BEGIN:VEVENT
 UID:ce6cc0e3ca1bb6a22783ace61034b12c57325b4e
 DTSTAMP:20230719T152822Z
 DTSTART;TZID=/freeassociation.sourceforge.net/Europe/Berlin:
- 20230831T180000
+ 20241005T140000
 DTEND;TZID=/freeassociation.sourceforge.net/Europe/Berlin:
- 20230831T220000
+ 20241005T220000
 SEQUENCE:3
 SUMMARY:dentist
 TRANSP:OPAQUE

tests/failed_cal.ics

@@ -0,0 +1,297 @@
+BEGIN:VCALENDAR
+CALSCALE:GREGORIAN
+PRODID:-//Ximian//NONSGML Evolution Calendar//EN
+VERSION:2.0
+X-EVOLUTION-DATA-REVISION:2024-11-06T05:14:31.539689Z(0)
+BEGIN:VTIMEZONE
+TZID:UTC
+BEGIN:STANDARD
+DTSTART;VALUE=DATE:16010101
+TZOFFSETFROM:+0000
+TZOFFSETTO:+0000
+END:STANDARD
+END:VTIMEZONE
+BEGIN:VTIMEZONE
+TZID:Europe/Berlin
+TZURL:http://tzurl.org/zoneinfo/Europe/Berlin
+X-LIC-LOCATION:Europe/Berlin
+BEGIN:DAYLIGHT
+TZOFFSETFROM:+0100
+TZOFFSETTO:+0200
+TZNAME:CEST
+DTSTART:19810329T020000
+RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=3
+END:DAYLIGHT
+BEGIN:STANDARD
+TZOFFSETFROM:+0200
+TZOFFSETTO:+0100
+TZNAME:CET
+DTSTART:19961027T030000
+RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=10
+END:STANDARD
+BEGIN:STANDARD
+TZOFFSETFROM:+005328
+TZOFFSETTO:+0100
+TZNAME:CET
+DTSTART:18930401T000000
+RDATE:18930401T000000
+END:STANDARD
+BEGIN:DAYLIGHT
+TZOFFSETFROM:+0100
+TZOFFSETTO:+0200
+TZNAME:CEST
+DTSTART:19160430T230000
+RDATE:19160430T230000
+RDATE:19170416T020000
+RDATE:19180415T020000
+RDATE:19400401T020000
+RDATE:19430329T020000
+RDATE:19440403T020000
+RDATE:19450402T020000
+RDATE:19460414T020000
+RDATE:19470406T030000
+RDATE:19480418T020000
+RDATE:19490410T020000
+RDATE:19800406T020000
+END:DAYLIGHT
+BEGIN:STANDARD
+TZOFFSETFROM:+0200
+TZOFFSETTO:+0100
+TZNAME:CET
+DTSTART:19161001T010000
+RDATE:19161001T010000
+RDATE:19170917T030000
+RDATE:19180916T030000
+RDATE:19421102T030000
+RDATE:19431004T030000
+RDATE:19441002T030000
+RDATE:19451118T030000
+RDATE:19461007T030000
+RDATE:19471005T030000
+RDATE:19481003T030000
+RDATE:19491002T030000
+RDATE:19800928T030000
+RDATE:19810927T030000
+RDATE:19820926T030000
+RDATE:19830925T030000
+RDATE:19840930T030000
+RDATE:19850929T030000
+RDATE:19860928T030000
+RDATE:19870927T030000
+RDATE:19880925T030000
+RDATE:19890924T030000
+RDATE:19900930T030000
+RDATE:19910929T030000
+RDATE:19920927T030000
+RDATE:19930926T030000
+RDATE:19940925T030000
+RDATE:19950924T030000
+END:STANDARD
+BEGIN:DAYLIGHT
+TZOFFSETFROM:+0200
+TZOFFSETTO:+0300
+TZNAME:CEMT
+DTSTART:19450524T020000
+RDATE:19450524T020000
+RDATE:19470511T030000
+END:DAYLIGHT
+BEGIN:DAYLIGHT
+TZOFFSETFROM:+0300
+TZOFFSETTO:+0200
+TZNAME:CEST
+DTSTART:19450924T030000
+RDATE:19450924T030000
+RDATE:19470629T030000
+END:DAYLIGHT
+BEGIN:STANDARD
+TZOFFSETFROM:+0100
+TZOFFSETTO:+0100
+TZNAME:CET
+DTSTART:19460101T000000
+RDATE:19460101T000000
+RDATE:19800101T000000
+END:STANDARD
+END:VTIMEZONE
+BEGIN:VTIMEZONE
+TZID:W. Europe Standard Time
+BEGIN:STANDARD
+DTSTART:16010101T030000
+TZOFFSETFROM:+0200
+TZOFFSETTO:+0100
+RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=10
+END:STANDARD
+BEGIN:DAYLIGHT
+DTSTART:16010101T020000
+TZOFFSETFROM:+0100
+TZOFFSETTO:+0200
+RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=3
+END:DAYLIGHT
+END:VTIMEZONE
+BEGIN:VTIMEZONE
+TZID:/freeassociation.sourceforge.net/Europe/Berlin
+X-LIC-LOCATION:Europe/Berlin
+BEGIN:STANDARD
+TZNAME:CET
+TZOFFSETFROM:+005328
+TZOFFSETTO:+0100
+DTSTART:18930401T000000
+END:STANDARD
+BEGIN:DAYLIGHT
+TZNAME:CEST
+TZOFFSETFROM:+0100
+TZOFFSETTO:+0200
+DTSTART:19160430T230000
+END:DAYLIGHT
+BEGIN:STANDARD
+TZNAME:CET
+TZOFFSETFROM:+0200
+TZOFFSETTO:+0100
+DTSTART:19161001T010000
+END:STANDARD
+BEGIN:DAYLIGHT
+TZNAME:CEST
+TZOFFSETFROM:+0100
+TZOFFSETTO:+0200
+DTSTART:19170416T020000
+RRULE:FREQ=YEARLY;UNTIL=19180415T010000Z;BYDAY=3MO;BYMONTH=4
+END:DAYLIGHT
+BEGIN:STANDARD
+TZNAME:CET
+TZOFFSETFROM:+0200
+TZOFFSETTO:+0100
+DTSTART:19170917T030000
+RRULE:FREQ=YEARLY;UNTIL=19180916T010000Z;BYDAY=3MO;BYMONTH=9
+END:STANDARD
+BEGIN:DAYLIGHT
+TZNAME:CEST
+TZOFFSETFROM:+0100
+TZOFFSETTO:+0200
+DTSTART:19400401T020000
+RDATE:19430329T020000
+END:DAYLIGHT
+BEGIN:STANDARD
+TZNAME:CET
+TZOFFSETFROM:+0200
+TZOFFSETTO:+0100
+DTSTART:19421102T030000
+END:STANDARD
+BEGIN:STANDARD
+TZNAME:CET
+TZOFFSETFROM:+0200
+TZOFFSETTO:+0100
+DTSTART:19431004T030000
+RRULE:FREQ=YEARLY;UNTIL=19441002T010000Z;BYDAY=1MO;BYMONTH=10
+END:STANDARD
+BEGIN:DAYLIGHT
+TZNAME:CEST
+TZOFFSETFROM:+0100
+TZOFFSETTO:+0200
+DTSTART:19440403T020000
+RRULE:FREQ=YEARLY;UNTIL=19450402T010000Z;BYDAY=1MO;BYMONTH=4
+END:DAYLIGHT
+BEGIN:DAYLIGHT
+TZNAME:CEMT
+TZOFFSETFROM:+0200
+TZOFFSETTO:+0300
+DTSTART:19450524T020000
+END:DAYLIGHT
+BEGIN:DAYLIGHT
+TZNAME:CEST
+TZOFFSETFROM:+0300
+TZOFFSETTO:+0200
+DTSTART:19450924T030000
+END:DAYLIGHT
+BEGIN:STANDARD
+TZNAME:CET
+TZOFFSETFROM:+0200
+TZOFFSETTO:+0100
+DTSTART:19451118T030000
+RDATE:19461007T030000
+END:STANDARD
+BEGIN:DAYLIGHT
+TZNAME:CEST
+TZOFFSETFROM:+0100
+TZOFFSETTO:+0200
+DTSTART:19460414T020000
+END:DAYLIGHT
+BEGIN:DAYLIGHT
+TZNAME:CEST
+TZOFFSETFROM:+0100
+TZOFFSETTO:+0200
+DTSTART:19470406T030000
+END:DAYLIGHT
+BEGIN:DAYLIGHT
+TZNAME:CEMT
+TZOFFSETFROM:+0200
+TZOFFSETTO:+0300
+DTSTART:19470511T030000
+END:DAYLIGHT
+BEGIN:DAYLIGHT
+TZNAME:CEST
+TZOFFSETFROM:+0300
+TZOFFSETTO:+0200
+DTSTART:19470629T030000
+END:DAYLIGHT
+BEGIN:STANDARD
+TZNAME:CET
+TZOFFSETFROM:+0200
+TZOFFSETTO:+0100
+DTSTART:19471005T030000
+RRULE:FREQ=YEARLY;UNTIL=19491002T010000Z;BYDAY=1SU;BYMONTH=10
+END:STANDARD
+BEGIN:DAYLIGHT
+TZNAME:CEST
+TZOFFSETFROM:+0100
+TZOFFSETTO:+0200
+DTSTART:19480418T020000
+RDATE:19490410T020000
+RDATE:19800406T020000
+END:DAYLIGHT
+BEGIN:STANDARD
+TZNAME:CET
+TZOFFSETFROM:+0200
+TZOFFSETTO:+0100
+DTSTART:19800928T030000
+RRULE:FREQ=YEARLY;UNTIL=19950924T010000Z;BYDAY=-1SU;BYMONTH=9
+END:STANDARD
+BEGIN:DAYLIGHT
+TZNAME:CEST
+TZOFFSETFROM:+0100
+TZOFFSETTO:+0200
+DTSTART:19810329T020000
+RRULE:FREQ=YEARLY;UNTIL=20370329T010000Z;BYDAY=-1SU;BYMONTH=3
+END:DAYLIGHT
+BEGIN:STANDARD
+TZNAME:CET
+TZOFFSETFROM:+0200
+TZOFFSETTO:+0100
+DTSTART:19961027T030000
+RRULE:FREQ=YEARLY;UNTIL=20361026T010000Z;BYDAY=-1SU;BYMONTH=10
+END:STANDARD
+BEGIN:STANDARD
+TZNAME:CET
+TZOFFSETFROM:+0200
+TZOFFSETTO:+0100
+DTSTART:20371025T030000
+RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=10
+END:STANDARD
+BEGIN:DAYLIGHT
+TZNAME:CEST
+TZOFFSETFROM:+0100
+TZOFFSETTO:+0200
+DTSTART:20380328T020000
+RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=3
+END:DAYLIGHT
+END:VTIMEZONE
+BEGIN:VEVENT
+DTSTAMP:20251106T051352Z
+DTSTART:20251215T080000Z
+DTEND:20251215T083000Z
+SUMMARY:Interview with John Doe
+DESCRIPTION:foo
+LOCATION:teams meeting
+UID:35a4a000-dc20-47c6-b2b0-b4cbbfbb114e
+CREATED:20241106T051431Z
+LAST-MODIFIED:20241106T051431Z
+END:VEVENT
+END:VCALENDAR

tests/run_tests.sh

@@ -0,0 +1,15 @@
+#!/bin/bash
+
+mapfile -t files < <(find ../tests/. -name "*.ics")
+
+i=1
+for file in ${files[@]}; do
+	echo "TEST ${i}: ${file}"
+	echo "===================================================="
+	../src/icscli -f "${file}"
+	echo "===================================================="
+	echo
+	((i++))
+done
+
+exit 0

tests/start_date_is_first_field.ics

@@ -0,0 +1,12 @@
+BEGIN:VCALENDAR
+BEGIN:VEVENT
+DTSTART:20240413T070000Z
+DTEND:20240413T083000Z
+DTSTAMP:20240229T171200Z
+SUMMARY:XYZ Exam (XYZ)
+DESCRIPTION:XYZ Exam (XYZ)
+UID:61792
+CREATED:20240229T171308Z
+LAST-MODIFIED:20240229T171308Z
+END:VEVENT
+END:VCALENDAR

unit-tests/meson.build

@@ -0,0 +1,16 @@
+project('ics_cli', 'c')
+
+t1e = executable('test_print_upcoming', 'test_print_upcoming.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')
+
+test('test print_upcoming', t1e)
+
+t2e = executable('test_pretty_print_date_time', 'test_pretty_print_date_time.c', '../src/string_handling.c', \
+'../src/date_time_handling.c', '../src/read_until_string.c', '../src/read_until_nl.c')
+
+test('test pretty_print_date_time', t2e)
+
+t3e = executable('test_parse_ics_file', 'test_parse_ics_file.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')
+
+test('test parse_ics_file', t3e)

unit-tests/test_parse_ics_file.c

@@ -0,0 +1,14 @@
+#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);
+
+	parse_ics_file("../../tests/failed_cal.ics", &head);
+
+	return 0;
+}

unit-tests/test_pretty_print_date_time.c

@@ -0,0 +1,50 @@
+#include "../src/date_time_handling.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <assert.h>
+
+int main() {
+	// 1
+	char* pdt = pretty_date_time("20251215T080000Z");
+
+	assert(!strcmp(pdt, "2025-12-15 08:00:00"));
+
+	free(pdt);
+
+	// 2
+	char* pdt2 = pretty_date_time("20251215T080000");
+
+	assert(!strcmp(pdt2, "2025-12-15 08:00:00"));
+
+	free(pdt2);
+
+	// 3
+	char* pdt3 = pretty_date_time("");
+
+	assert(!strcmp(pdt3, ""));
+
+	free(pdt3);
+
+	// 4
+	char* pdt4 = pretty_date_time("20251215");
+
+	assert(!strcmp(pdt4, "2025-12-15"));
+
+	free(pdt4);
+
+	// 5
+	char current_date[] = "20240710T103000";
+
+	printf("current_date: %s\n", current_date);
+	printf("strlen(current_date): %ld\n\n", strlen(current_date));
+
+	pretty_print_date_time(current_date);
+
+	printf("\n\ncurrent_date: %s\n", current_date);
+	printf("strlen(current_date): %ld\n", strlen(current_date));
+
+	pretty_print_date_time("20251215T080000Z");
+	printf("\n");
+
+	return 0;
+}

unit-tests/test_print_upcoming.c

@@ -0,0 +1,24 @@
+#include "../src/list_handling.h"
+#include "../src/parse_ics.h"
+#include <stdio.h>
+
+int main() {
+	// initialize empty list
+	struct event *head = NULL;
+
+	// 1
+	printf("\nTesting tests/failed_cal.ics:\n\n");
+	char *current_date = "20240710T113000";
+
+	printf("DEBUG - current_date: %s\n\n", current_date);
+
+	parse_ics_file("../../tests/failed_cal.ics", &head);
+
+	print_upcoming(head, current_date, 0);
+
+	// 2
+	printf("\nTesting tests/calendar.ics:\n\n");
+	parse_ics_file("../../tests/calendar.ics", &head);
+
+	print_upcoming(head, current_date, 0);
+}