test: add unit test for p1

internal/2025/DayTwo/code_test.go

@@ -0,0 +1,25 @@
+package daytwo
+
+import "testing"
+
+var testInput = []string{
+	"11-22",
+	"95-115",
+	"998-1012",
+	"1188511880-1188511890",
+	"222220-222224",
+	"1698522-1698528",
+	"446443-446449",
+	"38593856-38593862",
+	"565653-565659",
+	"824824821-824824827",
+	"2121212118-2121212124",
+}
+
+func TestPartOne(t *testing.T) {
+	expected := 1227775554
+	got := PartOne(testInput)
+	if got != expected {
+		t.Errorf("PartOne() = %d, want %d", got, expected)
+	}
+}