diff --git a/internal/2025/DayEight/code_test.go b/internal/2025/DayEight/code_test.go
new file mode 100644
index 0000000..fc1b197
--- /dev/null
+++ b/internal/2025/DayEight/code_test.go
@@ -0,0 +1,34 @@
+package dayeight
+
+import "testing"
+
+var testInput = []string{
+	"162,817,812",
+	"57,618,57",
+	"906,360,560",
+	"592,479,940",
+	"352,342,300",
+	"466,668,158",
+	"542,29,236",
+	"431,825,988",
+	"739,650,466",
+	"52,470,668",
+	"216,146,977",
+	"819,987,18",
+	"117,168,530",
+	"805,96,715",
+	"346,949,466",
+	"970,615,88",
+	"941,993,340",
+	"862,61,35",
+	"984,92,344",
+	"425,690,689",
+}
+
+func TestPartOne(t *testing.T) {
+	expected := 40
+	got := PartOne(testInput)
+	if got != expected {
+		t.Errorf("PartOne() = %d, want %d", got, expected)
+	}
+}