add day 4 cli and tests

main.go

@@ -23,6 +23,7 @@ var (
 		&day01{},
 		&day02{},
 		&day03{},
+		&day04{},
 	}
 )
 

main_test.go

@@ -81,3 +81,26 @@ func TestDay03(t *testing.T) {
 		t.Errorf("day 3 solution 1 = %s; wanted %s", res1, ans1)
 	}
 }
+
+func TestDay04(t *testing.T) {
+	input1 := `Card 1: 41 48 83 86 17 | 83 86  6 31 17  9 48 53
+Card 2: 13 32 20 16 61 | 61 30 68 82 17 32 24 19
+Card 3:  1 21 53 59 44 | 69 82 63 72 16 21 14  1
+Card 4: 41 92 73 84 69 | 59 84 76 51 58  5 54 83
+Card 5: 87 83 26 28 32 | 88 30 70 12 93 22 82 36
+Card 6: 31 18 13 56 72 | 74 77 10 23 35 67 36 11`
+
+	puzzle := day04{}
+	ans1 := "13"
+	res1 := puzzle.solve1(strings.NewReader(input1))
+	if res1 != ans1 {
+		t.Errorf("solve1() = %s; wanted %s", res1, ans1)
+	}
+
+	ans2 := "30"
+	res2 := puzzle.solve2(strings.NewReader(input1))
+	if res2 != ans2 {
+		t.Errorf("solve2() = %s; wanted %s", res2, ans2)
+	}
+
+}