test: add PartOne unit test

internal/2020/DaySeven/code_test.go

@@ -0,0 +1,23 @@
+package dayseven
+
+import "testing"
+
+var testInput = []string{
+	"light red bags contain 1 bright white bag, 2 muted yellow bags.",
+	"dark orange bags contain 3 bright white bags, 4 muted yellow bags.",
+	"bright white bags contain 1 shiny gold bag.",
+	"muted yellow bags contain 2 shiny gold bags, 9 faded blue bags.",
+	"shiny gold bags contain 1 dark olive bag, 2 vibrant plum bags.",
+	"dark olive bags contain 3 faded blue bags, 4 dotted black bags.",
+	"vibrant plum bags contain 5 faded blue bags, 6 dotted black bags.",
+	"faded blue bags contain no other bags.",
+	"dotted black bags contain no other bags.",
+}
+
+func TestPartOne(t *testing.T) {
+	expected := 4
+	got := PartOne(testInput)
+	if got != expected {
+		t.Errorf("PartOne() = %d, want %d", got, expected)
+	}
+}