test: add unit test for part one

internal/2020/DayEight/code_test.go

@@ -0,0 +1,23 @@
+package dayeight
+
+import "testing"
+
+var testInput = []string{
+	"nop +0",
+	"acc +1",
+	"jmp +4",
+	"acc +3",
+	"jmp -3",
+	"acc -99",
+	"acc +1",
+	"jmp -4",
+	"acc +6",
+}
+
+func TestPartOne(t *testing.T) {
+	expected := 5
+	got := PartOne(testInput)
+	if got != expected {
+		t.Errorf("PartOne() = %d, want %d", got, expected)
+	}
+}