Files
dnswatcher/internal/resolver/resolver_test.go
sneak 3959aedb6a
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Remove DNS mocking from tests; use live DNS everywhere
DNS is never mocked in this repository: tests exercise live DNS,
and robustness comes from handling real-world DNS behavior with
tolerant assertions and sensible timeouts, not from mocks.

watcher: drop mockResolver and wire the real iterative resolver
into the tests, querying stable public names (example.com,
www.example.com). Change detection is exercised by seeding the
state store with a synthetic previous observation that live DNS
cannot match (reserved .invalid nameserver names and RFC 5737
documentation addresses); DNS stays live in every run. The port
checker, TLS checker, and notifier remain test doubles since they
are not DNS, keeping notification and state assertions
deterministic against whatever addresses live DNS returns.

resolver: drop the timeoutClient fake DNSClient and the
NewFromLoggerWithClient mock constructor. The timeout test is
replaced by a live query against an RFC 5737 documentation
address where no nameserver can exist, asserting a classified
non-OK response with no records.

TESTING.md: extend the live-DNS policy to every package and
remove the carve-out that permitted DNS mocks in packages that
consume the resolver.

TODO.md: update stale references to hermetic mocked-DNS work to
reflect the no-mocking policy and the current state of
feature/resolver.

Intentionally dropped coverage: the exact StatusTimeout
classification (previously forced by the fake client) is no
longer asserted, because a genuinely unreachable server may fail
fast instead of timing out depending on the network path; the
live test tolerantly accepts any failure classification.
2026-08-07 20:43:09 +00:00

671 lines
13 KiB
Go

package resolver_test
import (
"context"
"log/slog"
"net"
"os"
"sort"
"strings"
"testing"
"time"
"github.com/stretchr/testify/assert"
"github.com/stretchr/testify/require"
"sneak.berlin/go/dnswatcher/internal/resolver"
)
// ----------------------------------------------------------------
// Test helpers
// ----------------------------------------------------------------
func newTestResolver(t *testing.T) *resolver.Resolver {
t.Helper()
log := slog.New(slog.NewTextHandler(
os.Stderr,
&slog.HandlerOptions{Level: slog.LevelDebug},
))
return resolver.NewFromLogger(log)
}
func testContext(t *testing.T) context.Context {
t.Helper()
ctx, cancel := context.WithTimeout(
context.Background(), 60*time.Second,
)
t.Cleanup(cancel)
return ctx
}
func findOneNSForDomain(
t *testing.T,
r *resolver.Resolver,
ctx context.Context, //nolint:revive // test helper
domain string,
) string {
t.Helper()
nameservers, err := r.FindAuthoritativeNameservers(
ctx, domain,
)
require.NoError(t, err)
require.NotEmpty(t, nameservers)
return nameservers[0]
}
// ----------------------------------------------------------------
// FindAuthoritativeNameservers tests
// ----------------------------------------------------------------
func TestFindAuthoritativeNameservers_ValidDomain(
t *testing.T,
) {
t.Parallel()
r := newTestResolver(t)
ctx := testContext(t)
nameservers, err := r.FindAuthoritativeNameservers(
ctx, "google.com",
)
require.NoError(t, err)
require.NotEmpty(t, nameservers)
hasGoogleNS := false
for _, ns := range nameservers {
if strings.Contains(ns, "google") {
hasGoogleNS = true
break
}
}
assert.True(t, hasGoogleNS,
"expected google nameservers, got: %v", nameservers,
)
}
func TestFindAuthoritativeNameservers_Subdomain(
t *testing.T,
) {
t.Parallel()
r := newTestResolver(t)
ctx := testContext(t)
nameservers, err := r.FindAuthoritativeNameservers(
ctx, "www.google.com",
)
require.NoError(t, err)
require.NotEmpty(t, nameservers)
}
func TestFindAuthoritativeNameservers_ReturnsSorted(
t *testing.T,
) {
t.Parallel()
r := newTestResolver(t)
ctx := testContext(t)
nameservers, err := r.FindAuthoritativeNameservers(
ctx, "google.com",
)
require.NoError(t, err)
assert.True(
t,
sort.StringsAreSorted(nameservers),
"nameservers should be sorted, got: %v", nameservers,
)
}
func TestFindAuthoritativeNameservers_Deterministic(
t *testing.T,
) {
t.Parallel()
r := newTestResolver(t)
ctx := testContext(t)
first, err := r.FindAuthoritativeNameservers(
ctx, "google.com",
)
require.NoError(t, err)
second, err := r.FindAuthoritativeNameservers(
ctx, "google.com",
)
require.NoError(t, err)
assert.Equal(t, first, second)
}
func TestFindAuthoritativeNameservers_TrailingDot(
t *testing.T,
) {
t.Parallel()
r := newTestResolver(t)
ctx := testContext(t)
ns1, err := r.FindAuthoritativeNameservers(
ctx, "google.com",
)
require.NoError(t, err)
ns2, err := r.FindAuthoritativeNameservers(
ctx, "google.com.",
)
require.NoError(t, err)
assert.Equal(t, ns1, ns2)
}
func TestFindAuthoritativeNameservers_CloudflareDomain(
t *testing.T,
) {
t.Parallel()
r := newTestResolver(t)
ctx := testContext(t)
nameservers, err := r.FindAuthoritativeNameservers(
ctx, "cloudflare.com",
)
require.NoError(t, err)
require.NotEmpty(t, nameservers)
for _, ns := range nameservers {
assert.True(t, strings.HasSuffix(ns, "."),
"NS should be FQDN with trailing dot: %s", ns,
)
}
}
// ----------------------------------------------------------------
// QueryNameserver tests
// ----------------------------------------------------------------
func TestQueryNameserver_BasicA(t *testing.T) {
t.Parallel()
r := newTestResolver(t)
ctx := testContext(t)
ns := findOneNSForDomain(t, r, ctx, "google.com")
resp, err := r.QueryNameserver(
ctx, ns, "www.google.com",
)
require.NoError(t, err)
require.NotNil(t, resp)
assert.Equal(t, resolver.StatusOK, resp.Status)
assert.Equal(t, ns, resp.Nameserver)
hasRecords := len(resp.Records["A"]) > 0 ||
len(resp.Records["CNAME"]) > 0
assert.True(t, hasRecords,
"expected A or CNAME records for www.google.com",
)
}
func TestQueryNameserver_AAAA(t *testing.T) {
t.Parallel()
r := newTestResolver(t)
ctx := testContext(t)
ns := findOneNSForDomain(t, r, ctx, "cloudflare.com")
resp, err := r.QueryNameserver(
ctx, ns, "cloudflare.com",
)
require.NoError(t, err)
aaaaRecords := resp.Records["AAAA"]
require.NotEmpty(t, aaaaRecords,
"cloudflare.com should have AAAA records",
)
for _, ip := range aaaaRecords {
parsed := net.ParseIP(ip)
require.NotNil(t, parsed,
"should be valid IP: %s", ip,
)
}
}
func TestQueryNameserver_MX(t *testing.T) {
t.Parallel()
r := newTestResolver(t)
ctx := testContext(t)
ns := findOneNSForDomain(t, r, ctx, "google.com")
resp, err := r.QueryNameserver(
ctx, ns, "google.com",
)
require.NoError(t, err)
mxRecords := resp.Records["MX"]
require.NotEmpty(t, mxRecords,
"google.com should have MX records",
)
}
func TestQueryNameserver_TXT(t *testing.T) {
t.Parallel()
r := newTestResolver(t)
ctx := testContext(t)
ns := findOneNSForDomain(t, r, ctx, "google.com")
resp, err := r.QueryNameserver(
ctx, ns, "google.com",
)
require.NoError(t, err)
txtRecords := resp.Records["TXT"]
require.NotEmpty(t, txtRecords,
"google.com should have TXT records",
)
hasSPF := false
for _, txt := range txtRecords {
if strings.Contains(txt, "v=spf1") {
hasSPF = true
break
}
}
assert.True(t, hasSPF,
"google.com should have SPF TXT record",
)
}
func TestQueryNameserver_NXDomain(t *testing.T) {
t.Parallel()
r := newTestResolver(t)
ctx := testContext(t)
ns := findOneNSForDomain(t, r, ctx, "google.com")
resp, err := r.QueryNameserver(
ctx, ns,
"this-surely-does-not-exist-xyz.google.com",
)
require.NoError(t, err)
assert.Equal(t, resolver.StatusNXDomain, resp.Status)
}
func TestQueryNameserver_RecordsSorted(t *testing.T) {
t.Parallel()
r := newTestResolver(t)
ctx := testContext(t)
ns := findOneNSForDomain(t, r, ctx, "google.com")
resp, err := r.QueryNameserver(
ctx, ns, "google.com",
)
require.NoError(t, err)
for recordType, values := range resp.Records {
assert.True(
t,
sort.StringsAreSorted(values),
"%s records should be sorted", recordType,
)
}
}
func TestQueryNameserver_ResponseIncludesNameserver(
t *testing.T,
) {
t.Parallel()
r := newTestResolver(t)
ctx := testContext(t)
ns := findOneNSForDomain(t, r, ctx, "cloudflare.com")
resp, err := r.QueryNameserver(
ctx, ns, "cloudflare.com",
)
require.NoError(t, err)
assert.Equal(t, ns, resp.Nameserver)
}
func TestQueryNameserver_EmptyRecordsOnNXDomain(
t *testing.T,
) {
t.Parallel()
r := newTestResolver(t)
ctx := testContext(t)
ns := findOneNSForDomain(t, r, ctx, "google.com")
resp, err := r.QueryNameserver(
ctx, ns,
"this-surely-does-not-exist-xyz.google.com",
)
require.NoError(t, err)
totalRecords := 0
for _, values := range resp.Records {
totalRecords += len(values)
}
assert.Zero(t, totalRecords)
}
func TestQueryNameserver_TrailingDotHandling(t *testing.T) {
t.Parallel()
r := newTestResolver(t)
ctx := testContext(t)
ns := findOneNSForDomain(t, r, ctx, "google.com")
resp1, err := r.QueryNameserver(
ctx, ns, "google.com",
)
require.NoError(t, err)
resp2, err := r.QueryNameserver(
ctx, ns, "google.com.",
)
require.NoError(t, err)
assert.Equal(t, resp1.Status, resp2.Status)
}
// ----------------------------------------------------------------
// QueryAllNameservers tests
// ----------------------------------------------------------------
func TestQueryAllNameservers_ReturnsAllNS(t *testing.T) {
t.Parallel()
r := newTestResolver(t)
ctx := testContext(t)
results, err := r.QueryAllNameservers(
ctx, "google.com",
)
require.NoError(t, err)
require.NotEmpty(t, results)
assert.GreaterOrEqual(t, len(results), 2)
for ns, resp := range results {
assert.Equal(t, ns, resp.Nameserver)
}
}
func TestQueryAllNameservers_AllReturnOK(t *testing.T) {
t.Parallel()
r := newTestResolver(t)
ctx := testContext(t)
results, err := r.QueryAllNameservers(
ctx, "google.com",
)
require.NoError(t, err)
for ns, resp := range results {
assert.Equal(
t, resolver.StatusOK, resp.Status,
"NS %s should return OK", ns,
)
}
}
func TestQueryAllNameservers_NXDomainFromAllNS(
t *testing.T,
) {
t.Parallel()
r := newTestResolver(t)
ctx := testContext(t)
results, err := r.QueryAllNameservers(
ctx,
"this-surely-does-not-exist-xyz.google.com",
)
require.NoError(t, err)
for ns, resp := range results {
assert.Equal(
t, resolver.StatusNXDomain, resp.Status,
"NS %s should return nxdomain", ns,
)
}
}
// ----------------------------------------------------------------
// LookupNS tests
// ----------------------------------------------------------------
func TestLookupNS_ValidDomain(t *testing.T) {
t.Parallel()
r := newTestResolver(t)
ctx := testContext(t)
nameservers, err := r.LookupNS(ctx, "google.com")
require.NoError(t, err)
require.NotEmpty(t, nameservers)
for _, ns := range nameservers {
assert.True(t, strings.HasSuffix(ns, "."),
"NS should have trailing dot: %s", ns,
)
}
}
func TestLookupNS_Sorted(t *testing.T) {
t.Parallel()
r := newTestResolver(t)
ctx := testContext(t)
nameservers, err := r.LookupNS(ctx, "google.com")
require.NoError(t, err)
assert.True(t, sort.StringsAreSorted(nameservers))
}
func TestLookupNS_MatchesFindAuthoritative(t *testing.T) {
t.Parallel()
r := newTestResolver(t)
ctx := testContext(t)
fromLookup, err := r.LookupNS(ctx, "google.com")
require.NoError(t, err)
fromFind, err := r.FindAuthoritativeNameservers(
ctx, "google.com",
)
require.NoError(t, err)
assert.Equal(t, fromFind, fromLookup)
}
// ----------------------------------------------------------------
// ResolveIPAddresses tests
// ----------------------------------------------------------------
func TestResolveIPAddresses_ReturnsIPs(t *testing.T) {
t.Parallel()
r := newTestResolver(t)
ctx := testContext(t)
ips, err := r.ResolveIPAddresses(ctx, "google.com")
require.NoError(t, err)
require.NotEmpty(t, ips)
for _, ip := range ips {
parsed := net.ParseIP(ip)
assert.NotNil(t, parsed,
"should be valid IP: %s", ip,
)
}
}
func TestResolveIPAddresses_Deduplicated(t *testing.T) {
t.Parallel()
r := newTestResolver(t)
ctx := testContext(t)
ips, err := r.ResolveIPAddresses(ctx, "google.com")
require.NoError(t, err)
seen := make(map[string]bool)
for _, ip := range ips {
assert.False(t, seen[ip], "duplicate IP: %s", ip)
seen[ip] = true
}
}
func TestResolveIPAddresses_Sorted(t *testing.T) {
t.Parallel()
r := newTestResolver(t)
ctx := testContext(t)
ips, err := r.ResolveIPAddresses(ctx, "google.com")
require.NoError(t, err)
assert.True(t, sort.StringsAreSorted(ips))
}
func TestResolveIPAddresses_NXDomainReturnsEmpty(
t *testing.T,
) {
t.Parallel()
r := newTestResolver(t)
ctx := testContext(t)
ips, err := r.ResolveIPAddresses(
ctx,
"this-surely-does-not-exist-xyz.google.com",
)
require.NoError(t, err)
assert.Empty(t, ips)
}
func TestResolveIPAddresses_CloudflareDomain(t *testing.T) {
t.Parallel()
r := newTestResolver(t)
ctx := testContext(t)
ips, err := r.ResolveIPAddresses(ctx, "cloudflare.com")
require.NoError(t, err)
require.NotEmpty(t, ips)
}
// ----------------------------------------------------------------
// Context cancellation tests
// ----------------------------------------------------------------
func TestFindAuthoritativeNameservers_ContextCanceled(
t *testing.T,
) {
t.Parallel()
r := newTestResolver(t)
ctx, cancel := context.WithCancel(context.Background())
cancel()
_, err := r.FindAuthoritativeNameservers(ctx, "google.com")
assert.Error(t, err)
}
func TestQueryNameserver_ContextCanceled(t *testing.T) {
t.Parallel()
r := newTestResolver(t)
ctx, cancel := context.WithCancel(context.Background())
cancel()
_, err := r.QueryNameserver(
ctx, "ns1.google.com.", "google.com",
)
assert.Error(t, err)
}
func TestQueryAllNameservers_ContextCanceled(t *testing.T) {
t.Parallel()
r := newTestResolver(t)
ctx, cancel := context.WithCancel(context.Background())
cancel()
_, err := r.QueryAllNameservers(ctx, "google.com")
assert.Error(t, err)
}
// ----------------------------------------------------------------
// Unreachable nameserver tests
// ----------------------------------------------------------------
func TestQueryNameserverIP_UnreachableServer(t *testing.T) {
t.Parallel()
r := newTestResolver(t)
ctx, cancel := context.WithTimeout(
context.Background(), 10*time.Second,
)
t.Cleanup(cancel)
// 192.0.2.1 is an RFC 5737 documentation address: no
// nameserver can exist there. Depending on the network
// path the queries either time out (silent drop) or fail
// fast (ICMP unreachable), so accept any non-OK status;
// the resolver must return a classified response with no
// records rather than an error or a hang.
resp, err := r.QueryNameserverIP(
ctx, "unreachable.test.", "192.0.2.1",
"example.com",
)
require.NoError(t, err)
assert.NotEqual(t, resolver.StatusOK, resp.Status)
totalRecords := 0
for _, values := range resp.Records {
totalRecords += len(values)
}
assert.Zero(t, totalRecords)
}
func TestResolveIPAddresses_ContextCanceled(t *testing.T) {
t.Parallel()
r := newTestResolver(t)
ctx, cancel := context.WithCancel(context.Background())
cancel()
_, err := r.ResolveIPAddresses(ctx, "google.com")
assert.Error(t, err)
}