diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..4c49bd7
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+.env
diff --git a/2021/common/aoc.go b/2021/common/aoc.go
new file mode 100644
index 0000000..483b2df
--- /dev/null
+++ b/2021/common/aoc.go
@@ -0,0 +1,96 @@
+package aoc
+
+import (
+	"bufio"
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"net/http"
+	"os"
+	"strings"
+
+	"github.com/joho/godotenv"
+)
+
+type testCase struct {
+	input string
+	result int
+}
+
+type adventOfCode struct {
+	year int
+	day int
+	testCases []testCase
+}
+
+func New(year int, day int) adventOfCode {
+	err := godotenv.Load()
+	if err != nil {
+		fmt.Println("Failed to open .env")
+	}
+
+	return adventOfCode{year, day, nil}
+}
+
+func (aoc adventOfCode) Solution(f func(*bufio.Scanner) int) {
+	if len(aoc.testCases) == 0 {
+		fmt.("No testCases provided!\n")
+	}
+
+	failed := false
+	for i, testCase := range aoc.testCases {
+		input := bufio.NewScanner(strings.NewReader(testCase.input))
+		result := f(input)
+
+		if result != testCase.result {
+			fmt.Printf("Test %d failed, expected '%d', got '%d'\n", i+1, testCase.result, result)
+			failed = true
+		} else {
+			fmt.Printf("Test %d passed!\n", i+1)
+		}
+	}
+	if failed {
+		return
+	}
+
+	input, err := aoc.getInput()
+	if err != nil {
+		panic(err)
+	}
+
+	result := f(input)
+	fmt.Printf("Solution: %d\n", result)
+}
+
+func (aoc *adventOfCode) Test(input string, result int) {
+	aoc.testCases = append(aoc.testCases, testCase{strings.TrimSpace(input), result})
+}
+
+func (aoc adventOfCode) getInput() (*bufio.Scanner, error) {
+	client := &http.Client{}
+
+	url := fmt.Sprintf("https://adventOfCode.com/%d/day/%d/input", aoc.year, aoc.day)
+	req, err := http.NewRequest("GET", url, nil)
+	if err != nil {
+		return nil, err
+	}
+
+	session := os.Getenv("SESSION")
+	cookie := fmt.Sprintf("session=%s", session)
+	req.Header.Set("Cookie", cookie)
+	resp, err := client.Do(req)
+	if err != nil {
+		return nil, err
+	}
+
+	if resp.StatusCode != 200 {
+		message, err := ioutil.ReadAll(resp.Body)
+		if err != err {
+			return nil, err
+		}
+		return nil, errors.New(string(message))
+	}
+
+	scanner := bufio.NewScanner(resp.Body)
+	return scanner, nil
+}
diff --git a/2021/common/go.mod b/2021/common/go.mod
new file mode 100644
index 0000000..8a990bc
--- /dev/null
+++ b/2021/common/go.mod
@@ -0,0 +1,5 @@
+module AoC/2021/common
+
+go 1.17
+
+require github.com/joho/godotenv v1.4.0 // indirect
diff --git a/2021/common/go.sum b/2021/common/go.sum
new file mode 100644
index 0000000..8c9f290
--- /dev/null
+++ b/2021/common/go.sum
@@ -0,0 +1,2 @@
+github.com/joho/godotenv v1.4.0 h1:3l4+N6zfMWnkbPEXKng2o2/MR5mSwTrBih4ZEkkz1lg=
+github.com/joho/godotenv v1.4.0/go.mod h1:f4LDr5Voq0i2e/R5DDNOoa2zzDfwtkZa6DnEwAbqwq4=