init

internal/resolv/resolv_test.go

@@ -0,0 +1,158 @@
+package resolv
+
+import (
+	"errors"
+	"os"
+	"path/filepath"
+	"reflect"
+	"sync"
+	"testing"
+)
+
+func newTestManager(t *testing.T, initial string) (*Manager, string) {
+	t.Helper()
+	dir := t.TempDir()
+	path := filepath.Join(dir, "resolv.conf")
+	if initial != "" {
+		if err := os.WriteFile(path, []byte(initial), 0o644); err != nil {
+			t.Fatalf("seed: %v", err)
+		}
+	}
+	return New(path), path
+}
+
+func readFile(t *testing.T, path string) string {
+	t.Helper()
+	b, err := os.ReadFile(path)
+	if err != nil {
+		t.Fatalf("read: %v", err)
+	}
+	return string(b)
+}
+
+func TestList_EmptyMissingFile(t *testing.T) {
+	m, _ := newTestManager(t, "")
+	got, err := m.List()
+	if err != nil {
+		t.Fatalf("List: %v", err)
+	}
+	if len(got) != 0 {
+		t.Fatalf("want empty, got %v", got)
+	}
+}
+
+func TestList_ParsesNameserversIgnoresOther(t *testing.T) {
+	const initial = `# comment
+; another comment
+search example.com
+nameserver 1.1.1.1
+options rotate
+nameserver 8.8.8.8
+nameserver 2001:4860:4860::8888
+`
+	m, _ := newTestManager(t, initial)
+	got, err := m.List()
+	if err != nil {
+		t.Fatalf("List: %v", err)
+	}
+	want := []string{"1.1.1.1", "8.8.8.8", "2001:4860:4860::8888"}
+	if !reflect.DeepEqual(got, want) {
+		t.Fatalf("want %v, got %v", want, got)
+	}
+}
+
+func TestAdd_AppendsAndPersists(t *testing.T) {
+	m, path := newTestManager(t, "search example.com\nnameserver 1.1.1.1\n")
+	if err := m.Add("8.8.8.8"); err != nil {
+		t.Fatalf("Add: %v", err)
+	}
+	got, _ := m.List()
+	want := []string{"1.1.1.1", "8.8.8.8"}
+	if !reflect.DeepEqual(got, want) {
+		t.Fatalf("list want %v, got %v", want, got)
+	}
+	content := readFile(t, path)
+	if want := "search example.com\nnameserver 1.1.1.1\nnameserver 8.8.8.8\n"; content != want {
+		t.Fatalf("file mismatch:\nwant: %q\ngot:  %q", want, content)
+	}
+}
+
+func TestAdd_RejectsInvalid(t *testing.T) {
+	m, _ := newTestManager(t, "")
+	for _, addr := range []string{"", "not-an-ip", "999.999.999.999", "1.1.1"} {
+		if err := m.Add(addr); !errors.Is(err, ErrInvalidAddress) {
+			t.Fatalf("Add(%q): want ErrInvalidAddress, got %v", addr, err)
+		}
+	}
+}
+
+func TestAdd_DuplicateRejected(t *testing.T) {
+	m, _ := newTestManager(t, "nameserver 1.1.1.1\n")
+	if err := m.Add("1.1.1.1"); !errors.Is(err, ErrAlreadyExists) {
+		t.Fatalf("want ErrAlreadyExists, got %v", err)
+	}
+}
+
+func TestRemove_DeletesEntry(t *testing.T) {
+	const initial = "search example.com\nnameserver 1.1.1.1\nnameserver 8.8.8.8\n"
+	m, path := newTestManager(t, initial)
+	if err := m.Remove("1.1.1.1"); err != nil {
+		t.Fatalf("Remove: %v", err)
+	}
+	got, _ := m.List()
+	if want := []string{"8.8.8.8"}; !reflect.DeepEqual(got, want) {
+		t.Fatalf("want %v, got %v", want, got)
+	}
+	content := readFile(t, path)
+	if want := "search example.com\nnameserver 8.8.8.8\n"; content != want {
+		t.Fatalf("file mismatch:\nwant: %q\ngot:  %q", want, content)
+	}
+}
+
+func TestRemove_NotFound(t *testing.T) {
+	m, _ := newTestManager(t, "nameserver 1.1.1.1\n")
+	if err := m.Remove("8.8.8.8"); !errors.Is(err, ErrNotFound) {
+		t.Fatalf("want ErrNotFound, got %v", err)
+	}
+}
+
+func TestRemove_InvalidAddress(t *testing.T) {
+	m, _ := newTestManager(t, "")
+	if err := m.Remove("nope"); !errors.Is(err, ErrInvalidAddress) {
+		t.Fatalf("want ErrInvalidAddress, got %v", err)
+	}
+}
+
+func TestConcurrentAddsConsistent(t *testing.T) {
+	m, _ := newTestManager(t, "")
+	addrs := []string{
+		"1.1.1.1", "8.8.8.8", "9.9.9.9", "8.8.4.4",
+		"1.0.0.1", "208.67.222.222", "208.67.220.220", "64.6.64.6",
+	}
+	var wg sync.WaitGroup
+	for _, a := range addrs {
+		wg.Add(1)
+		go func(a string) {
+			defer wg.Done()
+			if err := m.Add(a); err != nil {
+				t.Errorf("Add(%s): %v", a, err)
+			}
+		}(a)
+	}
+	wg.Wait()
+
+	got, err := m.List()
+	if err != nil {
+		t.Fatalf("List: %v", err)
+	}
+	if len(got) != len(addrs) {
+		t.Fatalf("want %d entries, got %d (%v)", len(addrs), len(got), got)
+	}
+	seen := make(map[string]bool, len(got))
+	for _, s := range got {
+		if seen[s] {
+			t.Fatalf("duplicate %s in %v", s, got)
+		}
+		seen[s] = true
+	}
+}