2021 Day 8

2021/aoc/stringset/stringset_test.go

@@ -0,0 +1,40 @@
+package stringset_test
+
+import (
+	"testing"
+
+	"github.com/jdkaplan/advent-of-code/aoc/stringset"
+)
+
+func TestMinus(t *testing.T) {
+	a := stringset.Runes("dab")
+	b := stringset.Runes("ab")
+	u := a.Minus(b)
+	if n := len(u); n != 1 {
+		t.Fatalf("Expected one value, got %d", n)
+	}
+	if v := u.Only(); v != "d" {
+		t.Errorf(`Expected value to be "d", got %s`, v)
+	}
+}
+
+func TestIntersect(t *testing.T) {
+	t.Run("pairwise", func(t *testing.T) {
+		u := stringset.Runes("dab").Intersect(stringset.Runes("ab"))
+		expected := stringset.Runes("ab")
+		if !u.Equal(expected) {
+			t.Errorf(`Expected value to be %s, got %s`, expected, u)
+		}
+	})
+
+	t.Run("multiple", func(t *testing.T) {
+		u := stringset.Intersect(
+			stringset.Runes("dab"),
+			stringset.Runes("ab"),
+		)
+		expected := stringset.Runes("ab")
+		if !u.Equal(expected) {
+			t.Errorf(`Expected value to be %s, got %s`, expected, u)
+		}
+	})
+}