refactor: clean up solution to part 1 on day 2

cmd/02/rnge/rnge_test.go

@@ -0,0 +1,57 @@
+package rnge_test
+
+import (
+	"slices"
+	"testing"
+
+	"github.com/StevanFreeborn/advent-of-code-2025/cmd/02/rnge"
+)
+
+func TestFrom(t *testing.T) {
+	expectedStart := int64(1000)
+	expectedEnd := int64(2000)
+
+	r := rnge.From("1000-2000")
+
+	if r.Start() != expectedStart {
+		t.Errorf("expected start %d, got %d", expectedStart, r.Start())
+	}
+
+	if r.End() != expectedEnd {
+		t.Errorf("expected end %d, got %d", expectedEnd, r.End())
+	}
+}
+
+func TestStart(t *testing.T) {
+	expectedStart := int64(500)
+
+	r := rnge.From("500-1500")
+
+	if r.Start() != expectedStart {
+		t.Errorf("expected start %d, got %d", expectedStart, r.Start())
+	}
+}
+
+func TestEnd(t *testing.T) {
+	expectedEnd := int64(1500)
+
+	r := rnge.From("500-1500")
+
+	if r.End() != expectedEnd {
+		t.Errorf("expected end %d, got %d", expectedEnd, r.End())
+	}
+}
+
+func TestInvalidIds(t *testing.T) {
+	r := rnge.From("1000-1100")
+	expectedInvalidIds := []int64{1010}
+	resultInvalidIds := []int64{}
+
+	for id := range r.InvalidIds() {
+		resultInvalidIds = append(resultInvalidIds, id)
+	}
+
+	if slices.Equal(resultInvalidIds, expectedInvalidIds) == false {
+		t.Errorf("expected invalid IDs %v, got %v", expectedInvalidIds, resultInvalidIds)
+	}
+}