ci: Add CI/CD script

.gitignore

@@ -1 +1,3 @@
 a.out
+main
+debug

.gitlab-ci.yml

@@ -0,0 +1,10 @@
+image: ${CI_REGISTRY}/ict/images/alpine/ci:latest
+
+before_script:
+  apk add build-base bash
+
+validate_code:
+  stage: test
+  script:
+    - chmod +x ./test/main.sh
+    - ./test/main.sh

test/main.sh

@@ -0,0 +1,82 @@
+#!/bin/bash
+
+CC_COMMAND='g++ -Wall -Wextra -Werror -pedantic -D__PROGTEST__'
+
+RED="\e[31m"
+GREEN="\e[32m"
+YELLOW="\e[33m"
+RESET="\e[0m"
+
+EXIT_STATUS=0
+
+_log() {
+	# 0 => Okay / Green
+	# 1 => Warn / Yellow
+	# 2 => Fail / Red
+	local log_level="$1"
+	local log_message="$2"
+
+	local log_color=""
+	local log_level_name=""
+	case "$log_level" in
+		0)
+			log_color="$GREEN"
+			log_level_name="OKAY"
+			;;
+		1)
+			log_color="$YELLOW"
+			log_level_name="WARN"
+			;;
+		2)
+			log_color="$RED"
+			log_level_name="FAIL"
+			;;
+	esac
+
+	printf "[${log_color}${log_level_name}${RESET}] %s\n" "$log_message"
+}
+
+for dir in homework-* exercise-*; do
+	if ! cd "$dir" > /dev/null; then
+		_log 2 "Couldn't cd into $dir"
+		cd ..
+		continue
+	fi
+
+	if [[ ! -f ./main.c ]]; then
+		_log 1 "No main.c file in $dir"
+		cd ..
+		continue
+	fi
+
+	if ! eval "$CC_COMMAND main.c"; then
+		_log 2 "Failed to compile code in $dir"
+		cd ..
+		continue
+	fi
+
+	failed_inputs=0
+	for input in test_data/*_in.txt; do
+
+		input_file=${input//*\/}
+		test_case_number=${input_file%%_in.txt}
+
+		command_output="$(diff <(./a.out < "test_data/${test_case_number}_in.txt") "test_data/${test_case_number}_out.txt")"
+
+		if [[ ! "$?" ]]; then
+			EXIT_STATUS=1
+			((failed_inputs++))
+			_log 2 "$dir (#$test_case_number)"
+			echo "$command_output"
+		fi
+
+	done
+
+	if ((failed_inputs == 0)); then
+		_log 0 "$dir"
+	fi
+
+	cd .. > /dev/null
+done
+
+exit $EXIT_STATUS