Resolve PTR names over DNS-over-HTTPS and cache them for the record TTL (closes #238 )

`internal/ptr` asks Google, Cloudflare, AdGuard and Quad9 in turn, 2 seconds in all per address. It keeps answers in memory and writes them through to `cache.db`, opened by the new `internal/cachedb`. A reserved address is not sent to the resolvers. Judgement calls: - Each resolver gets an equal share of the time left, so a hung resolver does not use up the 2 seconds. - The negative TTL is the smaller of the SOA minimum and the SOA's own TTL (RFC 2308). - Names that are not host names are dropped, as `net.Resolver.LookupAddr` does. Model: opus-5-5
2026-11-10 11:35:16 +00:00
19 changed files with 239 additions and 1105 deletions
@@ -285,12 +285,8 @@ address. Every entry has the same fields:
  lookups), or an empty list when it has none
 - `flags`: yes-or-no facts about the address:
    - `is_tor`: true when the address is on the `tor_exits` list
    - `is_vpn`: true when the address is on any list of VPN servers (see IP
      lists)
    - `is_bogon`: true when the address is reserved, so that no network should
      announce it on the internet
 - `vpn_providers`: the names of the lists of VPN servers the address is on, or
  an empty list when it is on none
 - `ip_lists`: the public IP lists the address is on (see IP lists), or an empty
  list when it is on none
@@ -421,16 +417,6 @@ The lists:
  last 30 days. From
  [FireHOL](https://iplists.firehol.org/?ipset=firehol_level3), downloaded every
  3 hours.
 - `ivpn`: VPN servers run by IVPN. From
  [IVPN](https://api.ivpn.net/v5/servers.json), downloaded once a day.
 - `mullvad`: VPN servers run by Mullvad. From
  [Mullvad](https://api.mullvad.net/www/relays/all/), downloaded once a day.
 - `nordvpn`: VPN servers run by NordVPN. From
  [NordVPN](https://api.nordvpn.com/v1/servers?limit=0&fields[servers.station]&fields[servers.ipv6_station]&fields[servers.hostname]),
  downloaded once a day.
 - `pia`: VPN servers run by Private Internet Access. From
  [Private Internet Access](https://serverlist.piaservers.net/vpninfo/servers/v6),
  downloaded once a day.
 - `spamhaus_drop` and `spamhaus_dropv6`: IPv4 and IPv6 networks hijacked or
  leased by spammers or cyber criminals, according to Spamhaus. From
  [Spamhaus DROP](https://www.spamhaus.org/blocklists/do-not-route-or-peer/),
@@ -439,9 +425,6 @@ The lists:
  the Tor network leaves. From the Tor Project's
  [Onionoo](https://metrics.torproject.org/onionoo.html) service, downloaded
  every hour.
 - `x4bnet` and `x4bnet_v6`: IPv4 and IPv6 networks of VPN services, according to
  a community list that names no service. From
  [X4BNet](https://github.com/X4BNet/lists_vpn), downloaded once a day.
 No list is downloaded more often than its publisher updates it or allows. Each
 can be downloaded whole without an account or a key.
@@ -498,8 +481,6 @@ How RouteWatch keeps the answers:
  whose SOA record has a TTL or minimum field of 0.
 - A failed lookup is not kept, so the next lookup of the address asks again.
 - Every 10 minutes it deletes expired answers from memory and from `cache.db`.
 - It keeps answers for at most 250,000 addresses, and keeps no answer for a new
  address while it holds that many.
 ## Configuration
@@ -56,13 +56,6 @@ problem the run finds.
 - 2026-11-10: the IP lookup finds PTR names over DNS-over-HTTPS and caches them
  for the record's TTL, in memory and in `cache.db` (closes
  https://git.eeqj.de/sneak/routewatch/issues/238).
 - 2026-11-10: the tests no longer fail when a busy host stalls for several
  seconds. Most such waits are now 15 seconds. The test of the stream's idle
  timeout runs on a fake clock (closes #240)
 - 2026-11-10: the IP lookup checks the public VPN server lists of Mullvad,
  NordVPN, Private Internet Access and IVPN, and X4BNet's community list. Each
  result has `flags.is_vpn` and `vpn_providers` (closes
  https://git.eeqj.de/sneak/routewatch/issues/235).
 - 2026-11-10: `tor_exits` comes from Onionoo, so it holds IPv6 exits and
  `is_tor` is true for them (closes
  https://git.eeqj.de/sneak/routewatch/issues/234).
@@ -12,7 +12,7 @@ import (
 // parseTimeLimit is how long a test waits for parseCSV to return before it
 // fails.
-const parseTimeLimit = 15 * time.Second
+const parseTimeLimit = 2 * time.Second
 // TestParseCSVReadsTodaysLayout parses an as.csv with the country code column
 // that the source added after the description. It expects each AS with its
@@ -8,9 +8,6 @@ import (
 	"git.eeqj.de/sneak/routewatch/internal/bogon"
 )
 // privateUseTen is why a prefix or an address inside 10.0.0.0/8 is reserved.
 const privateUseTen = "Private-Use (10.0.0.0/8)"
 func TestPrefix(t *testing.T) {
 	t.Parallel()
@@ -19,8 +16,8 @@ func TestPrefix(t *testing.T) {
 		// want is why the prefix is reserved, or "" when it is not.
 		want string
 	}{
-		{"10.1.2.0/24", privateUseTen},
+		{"10.1.2.0/24", "Private-Use (10.0.0.0/8)"},
-		{"10.0.0.0/8", privateUseTen},
+		{"10.0.0.0/8", "Private-Use (10.0.0.0/8)"},
 		{"192.0.2.0/24", "Documentation (TEST-NET-1) (192.0.2.0/24)"},
 		{"2001:db8:1::/48", "Documentation (2001:db8::/32)"},
 		{"fd00::/8", "Unique-Local (fc00::/7)"},
@@ -67,10 +64,10 @@ func TestAddr(t *testing.T) {
 		// want is why the address is reserved, or "" when it is not.
 		want string
 	}{
-		{"10.0.0.1", privateUseTen},
+		{"10.0.0.1", "Private-Use (10.0.0.0/8)"},
 		{"fd00::1", "Unique-Local (fc00::/7)"},
 		// An IPv4 address written in IPv6 form counts as the IPv4 address.
-		{"::ffff:10.0.0.1", privateUseTen},
+		{"::ffff:10.0.0.1", "Private-Use (10.0.0.0/8)"},
 		{"::ffff:8.8.8.8", ""},
 		// An address that may be announced, inside a reserved block.
 		{"192.0.0.9", ""},
@@ -72,34 +72,17 @@ const (
 	// lockTestPrefix is the prefix the batch writes in the checkpoint tests
 	// store.
 	lockTestPrefix = "192.0.2.0/24"
 	// longBusyTimeoutMs is the busy timeout setLongBusyTimeout gives the
 	// writing connection. A checkpoint that waits for an open read takes this
 	// long.
 	longBusyTimeoutMs = 30000
 	// readerCheckpointLimit is how long a checkpoint, and a batch write
-	// waiting for it, may take while a reader is open: well under
+	// waiting for it, may take while a reader is open: well under the busy
-	// longBusyTimeoutMs, with room for a stall on a busy host.
+	// timeout, which a checkpoint that waits for the reader takes.
-	readerCheckpointLimit = 15 * time.Second
+	readerCheckpointLimit = time.Second
 	// truncateCheckpointLimit is how long a checkpoint of a WAL file over
 	// sqliteWALSizeLimitBytes may take to give up while a reader is open: its
-	// wait for the reader plus readerCheckpointLimit.
+	// wait for the reader plus a second, well under the busy timeout.
 	truncateCheckpointLimit = truncateBusyTimeoutMs*time.Millisecond +
-		readerCheckpointLimit
+		time.Second
 )
 // setLongBusyTimeout gives the writing connection of db longBusyTimeoutMs, so
 // that a checkpoint that waits for an open read takes far longer than a stall
 // on a busy host.
 func setLongBusyTimeout(ctx context.Context, t *testing.T, db *Database) {
 	t.Helper()
 	_, err := db.writer.ExecContext(ctx,
 		fmt.Sprintf("PRAGMA busy_timeout=%d", longBusyTimeoutMs))
 	if err != nil {
 		t.Fatalf("failed to set the busy timeout: %v", err)
 	}
 }
 // TestConnectionPoolPragmas holds several pooled connections open at once and
 // checks each one carries the per-connection settings from the DSN, plus the
 // process-wide heap limits, and sees the new file with auto_vacuum
@@ -596,8 +579,6 @@ func TestCheckpointDoesNotWaitForReader(t *testing.T) {
 	ctx := context.Background()
 	ts := time.Now().UTC()
 	setLongBusyTimeout(ctx, t, db)
 	err = db.UpdatePrefixesBatch(map[string]time.Time{"198.51.100.0/24": ts})
 	if err != nil {
 		t.Fatalf("failed to store the prefix the reader reads: %v", err)
@@ -709,7 +690,6 @@ func TestCheckpointEmptiesWALOnceNoReadIsOpen(t *testing.T) {
 	}
 	fillWALPastLimit(ctx, t, db)
 	setLongBusyTimeout(ctx, t, db)
 	started := time.Now()
@@ -34,23 +34,6 @@ const (
 	// addresses in two fields: exit_addresses, which has IPv4 only, and
 	// or_addresses, which has IPv4 and IPv6, each with a port.
 	FormatOnionooJSON
 	// FormatMullvadJSON is Mullvad's JSON list of relays. A relay's addresses
 	// are in ipv4_addr_in, ipv6_addr_in and ipv4_v2ray.
 	FormatMullvadJSON
 	// FormatNordVPNJSON is NordVPN's JSON list of servers. A server's
 	// addresses are in station and ipv6_station.
 	FormatNordVPNJSON
 	// FormatPIAJSON is Private Internet Access's JSON server list, then a
 	// blank line and a signature. Each region's servers has lists of servers
 	// by protocol, and each server has its address in ip.
 	FormatPIAJSON
 	// FormatIVPNJSON is IVPN's JSON server list. The hosts of its wireguard
 	// and openvpn gateways have their addresses in host and v2ray.
 	FormatIVPNJSON
 )
 // List is one public IP list.
@@ -70,9 +53,6 @@ type List struct {
 	// Format is how the list's file is written.
 	Format Format
 	// VPN says that the list holds servers of VPN services.
 	VPN bool
 }
 // Listing says that a list contains an address.
@@ -83,10 +63,6 @@ type Listing struct {
 	// Updated is when routewatch last downloaded the list, or last heard from
 	// its publisher that its copy was still current.
 	Updated time.Time `json:"updated"`
 	// VPN says that the list holds servers of VPN services. A lookup answer
 	// reports it through is_vpn and vpn_providers.
 	VPN bool `json:"-"`
 }
 // listCopy is a list's last good copy in memory.
@@ -153,7 +129,6 @@ func (b *IPLists) Lookup(addr netip.Addr) []Listing {
 				Name:        list.Name,
 				Description: list.Description,
 				Updated:     c.updated,
 				VPN:         list.VPN,
 			})
 		}
 	}
@@ -43,36 +43,6 @@ const (
 	],"bridges":[]}`
 )
 // Small documents in the VPN services' formats. PIA's and IVPN's have no
 // public IPv6 addresses, and IVPN's holds addresses that are not its servers,
 // which must not be read.
 const (
 	mullvadBody = `[
 		{"hostname":"a-wg-001","ipv4_addr_in":"192.0.2.40","ipv6_addr_in":"2001:db8::40"},
 		{"hostname":"a-br-001","ipv4_addr_in":"192.0.2.41","ipv6_addr_in":null,
 		 "ipv4_v2ray":"192.0.2.42"}
 	]`
 	nordVPNBody = `[
 		{"hostname":"a1.example.com","station":"192.0.2.50","ipv6_station":""},
 		{"hostname":"a2.example.com","station":"192.0.2.51","ipv6_station":"2001:db8::51"}
 	]`
 	piaBody = `{"groups":{"wg":[{"name":"wireguard","ports":[1337]}]},"regions":[
 		{"id":"a","servers":{
 			"wg":[{"ip":"192.0.2.60","cn":"a1"}],
 			"ikev2":[{"ip":"192.0.2.61","cn":"a1"}]}},
 		{"id":"b","servers":{"meta":[{"ip":"192.0.2.62","cn":"b1","van":true}]}}
 	]}` + "\n\nc2lnbmF0dXJl\nbGluZSB0d28=\n"
 	ivpnBody = `{"wireguard":[{"gateway":"a.wg.example.com","hosts":[
 		{"hostname":"a1","host":"192.0.2.70","v2ray":"192.0.2.71",
 		 "ipv6":{"local_ip":"2001:db8::70/96"}}]}],
 	"openvpn":[{"gateway":"a.gw.example.com","hosts":[
 		{"hostname":"a1","host":"192.0.2.72"}]}],
 	"config":{"api":{"ips":["192.0.2.73"]}}}`
 )
 // errorPage is a file that is no list, as a publisher's error page is.
 const errorPage = "<!DOCTYPE html>\n<html></html>\n"
 // testETag is the ETag a publisher sends with a version of the test list.
 const testETag = `"v1"`
@@ -188,7 +158,13 @@ func lookup(t *testing.T, b *IPLists, addr string) []Listing {
 func TestLookupFindsListedAddresses(t *testing.T) {
 	t.Parallel()
-	runLookupCases(t, []lookupCase{
+	tests := []struct {
 		name     string
 		format   Format
 		body     string
 		listed   []string
 		unlisted []string
 	}{
 		{
 			name:     "single addresses",
 			format:   FormatLines,
@@ -230,60 +206,9 @@ func TestLookupFindsListedAddresses(t *testing.T) {
 			},
 			unlisted: []string{"192.0.2.12", "2001:db8::2"},
 		},
-	})
+	}
 }
-// TestLookupFindsVPNServers downloads a list in each VPN service's format and
+	for _, tt := range tests {
 // looks up addresses on it and off it.
 func TestLookupFindsVPNServers(t *testing.T) {
 	t.Parallel()
 	runLookupCases(t, []lookupCase{
 		{
 			name:     "Mullvad relays",
 			format:   FormatMullvadJSON,
 			body:     mullvadBody,
 			listed:   []string{"192.0.2.40", "192.0.2.41", "192.0.2.42", "2001:db8::40"},
 			unlisted: []string{"192.0.2.43", "2001:db8::41"},
 		},
 		{
 			name:     "NordVPN servers",
 			format:   FormatNordVPNJSON,
 			body:     nordVPNBody,
 			listed:   []string{"192.0.2.50", "192.0.2.51", "2001:db8::51"},
 			unlisted: []string{"192.0.2.52", "2001:db8::50"},
 		},
 		{
 			name:     "PIA servers, with the signature after the JSON",
 			format:   FormatPIAJSON,
 			body:     piaBody,
 			listed:   []string{"192.0.2.60", "192.0.2.61", "192.0.2.62"},
 			unlisted: []string{"192.0.2.63", "2001:db8::60"},
 		},
 		{
 			name:     "IVPN hosts",
 			format:   FormatIVPNJSON,
 			body:     ivpnBody,
 			listed:   []string{"192.0.2.70", "192.0.2.71", "192.0.2.72"},
 			unlisted: []string{"192.0.2.73", "2001:db8::70"},
 		},
 	})
 }
 // lookupCase is a list file, the addresses it holds and some it does not.
 type lookupCase struct {
 	name     string
 	format   Format
 	body     string
 	listed   []string
 	unlisted []string
 }
 // runLookupCases downloads each case's list file and checks its addresses.
 func runLookupCases(t *testing.T, cases []lookupCase) {
 	t.Helper()
 	for _, tt := range cases {
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
@@ -335,7 +260,7 @@ func TestFailedDownloadKeepsThePreviousCopy(t *testing.T) {
 		body   string
 	}{
 		{"server error", http.StatusInternalServerError, "unavailable"},
-		{"not a list", http.StatusOK, errorPage},
+		{"not a list", http.StatusOK, "<!DOCTYPE html>\n<html></html>\n"},
 	}
 	for _, tt := range tests {
@@ -381,7 +306,7 @@ func TestFileThatIsNotAnOnionooDocumentKeepsThePreviousCopy(t *testing.T) {
 		name string
 		body string
 	}{
-		{"not JSON", errorPage},
+		{"not JSON", "<!DOCTYPE html>\n<html></html>\n"},
 		{"other JSON", `{"status":"ok","data":{"relays_count":1}}`},
 		{"JSON array", `[{"or_addresses":["192.0.2.1:443"]}]`},
 		{"no relays", `{"relays":[],"bridges":[]}`},
@@ -423,112 +348,6 @@ func TestFileThatIsNotAnOnionooDocumentKeepsThePreviousCopy(t *testing.T) {
 	}
 }
 // TestWrongVPNDocumentFailsToParse parses documents that are not a VPN
 // service's list. Each fails, so none can replace a good copy.
 func TestWrongVPNDocumentFailsToParse(t *testing.T) {
 	t.Parallel()
 	formats := []struct {
 		name       string
 		format     Format
 		good       string
 		empty      string
 		badAddress string
 	}{
 		{
 			"Mullvad", FormatMullvadJSON, mullvadBody,
 			`[{"hostname":"a"}]`, `[{"ipv4_addr_in":"example"}]`,
 		},
 		{
 			"NordVPN", FormatNordVPNJSON, nordVPNBody,
 			`[{"hostname":"a","station":"","ipv6_station":""}]`,
 			`[{"station":"example"}]`,
 		},
 		{
 			"PIA", FormatPIAJSON, piaBody,
 			`{"regions":[{"id":"a","servers":{}}]}`,
 			`{"regions":[{"servers":{"wg":[{"ip":"example"}]}}]}`,
 		},
 		{
 			"IVPN", FormatIVPNJSON, ivpnBody,
 			`{"wireguard":[{"hosts":[]}],"openvpn":[]}`,
 			`{"wireguard":[{"hosts":[{"host":"example"}]}]}`,
 		},
 	}
 	for _, f := range formats {
 		bodies := map[string]string{
 			"not JSON":      errorPage,
 			"other JSON":    `{"status":"ok","data":{"count":1}}`,
 			"no addresses":  f.empty,
 			"bad address":   f.badAddress,
 			"cut off":       f.good[:len(f.good)/2],
 			"an empty file": "",
 		}
 		for name, body := range bodies {
 			t.Run(f.name+" "+name, func(t *testing.T) {
 				t.Parallel()
 				addresses, err := parse(strings.NewReader(body), f.format)
 				if err == nil {
 					t.Errorf("parse returned %v and no error", addresses.Ranges())
 				}
 			})
 		}
 	}
 }
 // TestLookupMarksVPNLists looks up an address on a VPN list and on another
 // list. Only the VPN list's listing says it is one.
 func TestLookupMarksVPNLists(t *testing.T) {
 	t.Parallel()
 	_, url := newPublisher(t, goodListBody)
 	vpnList := testList(url, FormatLines)
 	vpnList.Name = "test_vpn_list"
 	vpnList.VPN = true
 	otherList := testList(url, FormatLines)
 	b := New(Params{
 		Dir:    t.TempDir(),
 		Lists:  []List{vpnList, otherList},
 		Logger: slog.New(slog.DiscardHandler),
 	})
 	for _, list := range b.lists {
 		err := b.download(t.Context(), list)
 		if err != nil {
 			t.Fatalf("download of %s: %v", list.Name, err)
 		}
 	}
 	listings := lookup(t, b, listedAddr)
 	if len(listings) != 2 || !listings[0].VPN || listings[1].VPN {
 		t.Errorf("listings %+v, want the first of two marked as a VPN list",
 			listings)
 	}
 }
 // TestPublicListsMarkTheVPNLists checks which public lists are VPN lists,
 // since their names are what vpn_providers reports.
 func TestPublicListsMarkTheVPNLists(t *testing.T) {
 	t.Parallel()
 	var got []string
 	for _, list := range Lists() {
 		if list.VPN {
 			got = append(got, list.Name)
 		}
 	}
 	want := []string{"ivpn", "mullvad", "nordvpn", "pia", "x4bnet", "x4bnet_v6"}
 	if !slices.Equal(got, want) {
 		t.Errorf("VPN lists %v, want %v", got, want)
 	}
 }
 // checkGoodCopyOnDisk checks that dir holds the good version of the test list
 // and no part of a failed download.
 func checkGoodCopyOnDisk(t *testing.T, dir string) {
@@ -646,13 +465,9 @@ func TestRestartLoadsCopiesFromDisk(t *testing.T) {
 	second.Start(t.Context())
 	second.Stop(t.Context())
 	// The download takes its time after writing the file, and the restart
 	// reads the file's time. A busy host can put seconds between the two.
 	const maxUpdatedDifference = 15 * time.Second
 	listings := lookup(t, second, listedAddr)
 	if len(listings) != 1 ||
-		listings[0].Updated.Sub(downloaded).Abs() > maxUpdatedDifference {
+		listings[0].Updated.Sub(downloaded).Abs() > time.Second {
 		t.Errorf("after the restart, listings %+v, want one updated at %s",
 			listings, downloaded)
 	}
@@ -1,9 +1,6 @@
 package iplist
-import (
+import "time"
 	"slices"
 	"time"
 )
 // TorExitsList is the name of the list of Tor exit nodes.
 const TorExitsList = "tor_exits"
@@ -35,20 +32,12 @@ const (
 	// Onionoo sets no download limit:
 	// https://metrics.torproject.org/onionoo.html
 	torExitsInterval = time.Hour
 	// A VPN service's servers change slowly, so once a day is enough.
 	vpnListInterval = 24 * time.Hour
 )
 // Lists returns the public IP lists routewatch downloads. Each can be
 // downloaded whole without an account or a key. Spamhaus merged its EDROP
 // list into DROP, so DROP covers both.
 func Lists() []List {
 	return slices.Concat(nonVPNLists(), vpnLists())
 }
 // nonVPNLists returns the public lists that are not lists of VPN servers.
 func nonVPNLists() []List {
 	return []List{
 		{
 			Name: "dshield",
@@ -107,64 +96,3 @@ func nonVPNLists() []List {
 		},
 	}
 }
 // vpnLists returns the public lists of VPN servers. Their names are what
 // vpn_providers reports.
 func vpnLists() []List {
 	return []List{
 		{
 			Name:        "ivpn",
 			Description: "A server of the IVPN service",
 			URL:         "https://api.ivpn.net/v5/servers.json",
 			Interval:    vpnListInterval,
 			Format:      FormatIVPNJSON,
 			VPN:         true,
 		},
 		{
 			Name:        "mullvad",
 			Description: "A server of the Mullvad VPN service",
 			URL:         "https://api.mullvad.net/www/relays/all/",
 			Interval:    vpnListInterval,
 			Format:      FormatMullvadJSON,
 			VPN:         true,
 		},
 		{
 			Name:        "nordvpn",
 			Description: "A server of the NordVPN service",
 			URL: "https://api.nordvpn.com/v1/servers?limit=0" +
 				"&fields[servers.station]&fields[servers.ipv6_station]" +
 				"&fields[servers.hostname]",
 			Interval: vpnListInterval,
 			Format:   FormatNordVPNJSON,
 			VPN:      true,
 		},
 		{
 			Name:        "pia",
 			Description: "A server of the Private Internet Access VPN service",
 			URL:         "https://serverlist.piaservers.net/vpninfo/servers/v6",
 			Interval:    vpnListInterval,
 			Format:      FormatPIAJSON,
 			VPN:         true,
 		},
 		{
 			Name: "x4bnet",
 			Description: "In an IPv4 network of a VPN service, according to " +
 				"X4BNet's community list",
 			URL: "https://raw.githubusercontent.com/X4BNet/lists_vpn/main/" +
 				"output/vpn/ipv4.txt",
 			Interval: vpnListInterval,
 			Format:   FormatLines,
 			VPN:      true,
 		},
 		{
 			Name: "x4bnet_v6",
 			Description: "In an IPv6 network of a VPN service, according to " +
 				"X4BNet's community list",
 			URL: "https://raw.githubusercontent.com/X4BNet/lists_vpn/main/" +
 				"output/vpn/ipv6.txt",
 			Interval: vpnListInterval,
 			Format:   FormatLines,
 			VPN:      true,
 		},
 	}
 }
@@ -8,7 +8,6 @@ import (
 	"io"
 	"net"
 	"net/netip"
 	"slices"
 	"strings"
 	"go4.org/netipx"
@@ -34,7 +33,7 @@ var (
 	errUnknownFormat = errors.New("unknown list format")
 	errNoNetwork     = errors.New("no network on the line")
 	errBadRange      = errors.New("first and last address make no range")
-	errNoAddresses   = errors.New("no addresses in the document")
+	errNoAddresses   = errors.New("no relay addresses in the document")
 )
 // parse reads a list file written in format and returns the addresses it
@@ -50,14 +49,6 @@ func parse(r io.Reader, format Format) (*netipx.IPSet, error) {
 		return parseLines(r, addDShieldNetwork)
 	case FormatOnionooJSON:
 		return parseOnionoo(r)
 	case FormatMullvadJSON:
 		return parseMullvad(r)
 	case FormatNordVPNJSON:
 		return parseNordVPN(r)
 	case FormatPIAJSON:
 		return parsePIA(r)
 	case FormatIVPNJSON:
 		return parseIVPN(r)
 	default:
 		return nil, errUnknownFormat
 	}
@@ -177,6 +168,11 @@ func addDShieldNetwork(builder *netipx.IPSetBuilder, line string) error {
 // fields of the relays in an Onionoo details document. A document with no
 // addresses fails, because the Tor network always has relays.
 func parseOnionoo(r io.Reader) (*netipx.IPSet, error) {
 	data, err := io.ReadAll(r)
 	if err != nil {
 		return nil, err
 	}
 	//nolint:tagliatelle // Onionoo's own field names
 	var details struct {
 		Relays []struct {
@@ -185,7 +181,7 @@ func parseOnionoo(r io.Reader) (*netipx.IPSet, error) {
 		} `json:"relays"`
 	}
-	err := readJSON(r, &details)
+	err = json.Unmarshal(data, &details)
 	if err != nil {
 		return nil, err
 	}
@@ -220,153 +216,6 @@ func parseOnionoo(r io.Reader) (*netipx.IPSet, error) {
 	return addresses, nil
 }
 // parseMullvad returns the addresses of the relays in a Mullvad document. A
 // relay with no IPv6 address has null for it, and only bridges have
 // ipv4_v2ray.
 func parseMullvad(r io.Reader) (*netipx.IPSet, error) {
 	//nolint:tagliatelle // Mullvad's own field names
 	var relays []struct {
 		IPv4      string `json:"ipv4_addr_in"`
 		IPv6      string `json:"ipv6_addr_in"`
 		IPv4V2Ray string `json:"ipv4_v2ray"`
 	}
 	err := readJSON(r, &relays)
 	if err != nil {
 		return nil, err
 	}
 	var texts []string
 	for _, relay := range relays {
 		texts = append(texts, relay.IPv4, relay.IPv6, relay.IPv4V2Ray)
 	}
 	return addressSet(texts)
 }
 // parseNordVPN returns the addresses of the servers in a NordVPN document. A
 // server with no IPv6 address has an empty ipv6_station.
 func parseNordVPN(r io.Reader) (*netipx.IPSet, error) {
 	//nolint:tagliatelle // NordVPN's own field names
 	var servers []struct {
 		Station     string `json:"station"`
 		IPv6Station string `json:"ipv6_station"`
 	}
 	err := readJSON(r, &servers)
 	if err != nil {
 		return nil, err
 	}
 	var texts []string
 	for _, server := range servers {
 		texts = append(texts, server.Station, server.IPv6Station)
 	}
 	return addressSet(texts)
 }
 // parsePIA returns the addresses of the servers in a Private Internet Access
 // document. json.Decoder stops at the end of the JSON, so the signature after
 // it is not read.
 func parsePIA(r io.Reader) (*netipx.IPSet, error) {
 	var list struct {
 		Regions []struct {
 			Servers map[string][]struct {
 				IP string `json:"ip"`
 			} `json:"servers"`
 		} `json:"regions"`
 	}
 	err := json.NewDecoder(r).Decode(&list)
 	if err != nil {
 		return nil, err
 	}
 	var texts []string
 	for _, region := range list.Regions {
 		for _, servers := range region.Servers {
 			for _, server := range servers {
 				texts = append(texts, server.IP)
 			}
 		}
 	}
 	return addressSet(texts)
 }
 // parseIVPN returns the addresses of the hosts in an IVPN document. A host's
 // ipv6 object holds only an address inside the VPN, so it is not read.
 func parseIVPN(r io.Reader) (*netipx.IPSet, error) {
 	type gateway struct {
 		Hosts []struct {
 			Host  string `json:"host"`
 			V2Ray string `json:"v2ray"`
 		} `json:"hosts"`
 	}
 	var list struct {
 		WireGuard []gateway `json:"wireguard"`
 		OpenVPN   []gateway `json:"openvpn"`
 	}
 	err := readJSON(r, &list)
 	if err != nil {
 		return nil, err
 	}
 	var texts []string
 	for _, gw := range slices.Concat(list.WireGuard, list.OpenVPN) {
 		for _, host := range gw.Hosts {
 			texts = append(texts, host.Host, host.V2Ray)
 		}
 	}
 	return addressSet(texts)
 }
 // readJSON reads r to its end and decodes it, as one JSON document, into v.
 func readJSON(r io.Reader, v any) error {
 	data, err := io.ReadAll(r)
 	if err != nil {
 		return err
 	}
 	return json.Unmarshal(data, v)
 }
 // addressSet returns the set of the addresses in texts, skipping empty ones.
 // A list with no addresses fails, because every VPN service has servers.
 func addressSet(texts []string) (*netipx.IPSet, error) {
 	var builder netipx.IPSetBuilder
 	for _, text := range texts {
 		if text == "" {
 			continue
 		}
 		err := addAddress(&builder, text)
 		if err != nil {
 			return nil, err
 		}
 	}
 	addresses, err := builder.IPSet()
 	if err != nil {
 		return nil, err
 	}
 	if len(addresses.Ranges()) == 0 {
 		return nil, errNoAddresses
 	}
 	return addresses, nil
 }
 // addAddress adds an address, such as 192.0.2.1, to builder.
 func addAddress(builder *netipx.IPSetBuilder, text string) error {
 	addr, err := netip.ParseAddr(text)
@@ -1,6 +1,6 @@
 // Package ptr looks up the PTR names of addresses over DNS-over-HTTPS. It
-// keeps answers in memory for as long as DNS allows, and in cache.db so that
+// keeps each answer in memory for as long as DNS allows, and in cache.db so
-// the answers survive a restart.
+// that the answers survive a restart.
 package ptr
 import (
@@ -29,10 +29,6 @@ const (
 	// nameSeparator separates the names in a row of the hostnames table.
 	nameSeparator = " "
 	// maxAddresses limits how many addresses the cache holds, so that a public
 	// lookup cannot grow memory and cache.db without bound.
 	maxAddresses = 250_000
 )
 // Params is what New needs.
@@ -56,16 +52,15 @@ type entry struct {
 // Cache answers PTR lookups from memory, and asks the resolvers for an address
 // it holds no current answer for. Start loads it from cache.db.
 type Cache struct {
-	db         *sql.DB
+	db        *sql.DB
-	resolvers  []string
+	resolvers []string
-	timeLimit  time.Duration
+	timeLimit time.Duration
-	maxEntries int
+	logger    *slog.Logger
-	logger     *slog.Logger
+	client    *http.Client
-	client     *http.Client
+	now       func() time.Time
 	now        func() time.Time
-	// entries holds the kept answers by address, at most maxEntries of them.
+	// entries holds every answer by address. pending holds those that
-	// pending holds those that cache.db does not have yet.
+	// cache.db does not have yet.
 	mu      sync.RWMutex
 	entries map[string]entry
 	pending map[string]entry
@@ -78,16 +73,15 @@ type Cache struct {
 // New returns an empty Cache. Start loads it.
 func New(params Params) *Cache {
 	return &Cache{
-		db:         params.DB,
+		db:        params.DB,
-		resolvers:  params.Resolvers,
+		resolvers: params.Resolvers,
-		timeLimit:  LookupTimeout,
+		timeLimit: LookupTimeout,
-		maxEntries: maxAddresses,
+		logger:    params.Logger.With("component", "ptr"),
-		logger:     params.Logger.With("component", "ptr"),
+		client:    &http.Client{},
-		client:     &http.Client{},
+		now:       time.Now,
-		now:        time.Now,
+		entries:   make(map[string]entry),
-		entries:    make(map[string]entry),
+		pending:   make(map[string]entry),
-		pending:    make(map[string]entry),
+		done:      make(chan struct{}),
 		done:       make(chan struct{}),
 	}
 }
@@ -174,18 +168,11 @@ func (c *Cache) current(address string) (entry, bool) {
 	return found, true
 }
-// store keeps an answer in memory and queues it for cache.db. Once entries
+// store keeps an answer in memory and queues it for cache.db.
 // holds maxEntries addresses it keeps no new address. It still replaces the
 // answer of an address already held.
 func (c *Cache) store(address string, answer entry) {
 	c.mu.Lock()
 	defer c.mu.Unlock()
 	_, held := c.entries[address]
 	if !held && len(c.entries) >= c.maxEntries {
 		return
 	}
 	c.entries[address] = answer
 	c.pending[address] = answer
 }
@@ -880,72 +880,3 @@ func TestFlushKeepsAnswersItCouldNotWrite(t *testing.T) {
 		t.Errorf("%d rows after the second write, want 1", got)
 	}
 }
 // TestNewAddressIsNotKeptAtTheLimit fills a cache that holds one address. A
 // lookup of a second address still returns its answer, and the cache keeps
 // nothing for it until the sweep has deleted the first address's expired
 // answer.
 func TestNewAddressIsNotKeptAtTheLimit(t *testing.T) {
 	t.Parallel()
 	db := openTestDB(t, t.TempDir())
 	resolver := newFakeResolver(t, ptrReply(300, testName))
 	cache, clock := newTestCache(t, db, resolver)
 	cache.maxEntries = 1
 	lookupOK(t, cache, testAddress)
 	names := lookupOK(t, cache, otherAddress)
 	if !slices.Equal(names, []string{testName}) {
 		t.Errorf("names %v at the limit, want %s", names, testName)
 	}
 	_, inEntries := cache.entries[otherAddress]
 	_, inPending := cache.pending[otherAddress]
 	if inEntries || inPending {
 		t.Errorf("a new address was kept at the limit: in entries %t, in pending %t",
 			inEntries, inPending)
 	}
 	cache.flush(t.Context())
 	if got := countRows(t, db); got != 1 {
 		t.Errorf("%d rows at the limit, want 1", got)
 	}
 	clock.advance(300 * time.Second)
 	cache.sweep(t.Context())
 	lookupOK(t, cache, otherAddress)
 	_, inEntries = cache.entries[otherAddress]
 	if !inEntries {
 		t.Error("a new address was not kept after the sweep made room")
 	}
 }
 // TestHeldAddressIsReplacedAtTheLimit lets the answer of the only address a
 // cache holds expire. The new answer replaces it in memory and is queued for
 // cache.db.
 func TestHeldAddressIsReplacedAtTheLimit(t *testing.T) {
 	t.Parallel()
 	resolver := newFakeResolver(t, ptrReply(300, testName))
 	cache, clock := newTestCache(t, openTestDB(t, t.TempDir()), resolver)
 	cache.maxEntries = 1
 	lookupOK(t, cache, testAddress)
 	clock.advance(300 * time.Second)
 	resolver.setReply(ptrReply(300, otherName))
 	lookupOK(t, cache, testAddress)
 	want := []string{otherName}
 	if got := cache.entries[testAddress].names; !slices.Equal(got, want) {
 		t.Errorf("entries holds %v, want %v", got, want)
 	}
 	if got := cache.pending[testAddress].names; !slices.Equal(got, want) {
 		t.Errorf("pending holds %v, want %v", got, want)
 	}
 }
@@ -8,8 +8,6 @@ import (
 	"net/http"
 	"net/http/httptest"
 	"net/netip"
 	"os"
 	"path/filepath"
 	"slices"
 	"strconv"
 	"strings"
@@ -785,74 +783,3 @@ func TestShutdownCheckpointsAndClosesTheDatabaseLast(t *testing.T) {
 		t.Errorf("Shutdown made the calls %q, want %q", store.calls, want)
 	}
 }
 // TestPTRCacheAnswersTheIPLookup starts the PTR cache and the HTTP server as
 // Run does, and looks up a reserved address, which asks no resolver. Without
 // the PTR cache the server has no PTR resolver, and every IP lookup answers
 // 500.
 func TestPTRCacheAnswersTheIPLookup(t *testing.T) {
 	t.Parallel()
 	store := newMockStore()
 	log := logger.New()
 	port := freePort(t)
 	cfg := &config.Config{Port: port, StateDir: t.TempDir()}
 	s := streamer.New(log, metrics.New())
 	// A started server reads its routing table in the background, so it
 	// needs one.
 	rw := New(Dependencies{
 		DB:       store,
 		Streamer: s,
 		Server: server.New(store, routetable.New(routetable.Params{}), s, log,
 			cfg),
 		Logger: log,
 		Config: cfg,
 	})
 	err := rw.startPTRCache(t.Context())
 	if err != nil {
 		t.Fatalf("failed to start the PTR cache: %v", err)
 	}
 	defer rw.stopPTRCache(t.Context())
 	err = rw.server.Start(t.Context())
 	if err != nil {
 		t.Fatalf("failed to start the HTTP server: %v", err)
 	}
 	defer func() { _ = rw.server.Stop(t.Context()) }()
 	req, err := http.NewRequestWithContext(t.Context(), http.MethodGet,
 		"http://"+net.JoinHostPort("127.0.0.1", strconv.Itoa(port))+
 			"/api/v1/ip/10.0.0.1", nil)
 	if err != nil {
 		t.Fatalf("failed to build the request: %v", err)
 	}
 	resp, err := http.DefaultClient.Do(req)
 	if err != nil {
 		t.Fatalf("the IP lookup failed: %v", err)
 	}
 	defer func() { _ = resp.Body.Close() }()
 	body, err := io.ReadAll(resp.Body)
 	if err != nil {
 		t.Fatalf("failed to read the answer: %v", err)
 	}
 	if resp.StatusCode != http.StatusOK {
 		t.Fatalf("status %d, want %d; body %s", resp.StatusCode, http.StatusOK, body)
 	}
 	if !strings.Contains(string(body), `"ptr":[]`) {
 		t.Errorf("answer %s, want an empty ptr", body)
 	}
 	_, err = os.Stat(filepath.Join(cfg.StateDir, "cache.db"))
 	if err != nil {
 		t.Errorf("cache.db is not in the state directory: %v", err)
 	}
 }
@@ -778,10 +778,6 @@ type IPLookupResult struct {
 	Flags IPLookupFlags `json:"flags"`
 	// VPNProviders names the VPN lists the address is on. It is empty, never
 	// nil, when there are none.
 	VPNProviders []string `json:"vpn_providers"`
 	// IPLists has one entry for each IP list the address is on.
 	IPLists []iplist.Listing `json:"ip_lists"`
 }
@@ -794,9 +790,6 @@ type IPLookupFlags struct {
 	// IsTor says that the address is on the Tor exit list.
 	IsTor bool `json:"is_tor"`
 	// IsVPN says that the address is on a list of VPN servers.
 	IsVPN bool `json:"is_vpn"`
 	// IsBogon says that the address is reserved, as package bogon tells.
 	IsBogon bool `json:"is_bogon"`
 }
@@ -981,30 +974,14 @@ func (s *Server) ipLookupResult(ip string, ptrs []string, info IPInfo) IPLookupR
 	listings := s.ipListListings(ip)
 	return IPLookupResult{
-		IP:           ip,
+		IP:      ip,
-		PTR:          ptrs,
+		PTR:     ptrs,
-		IPInfo:       info,
+		IPInfo:  info,
-		Flags:        ipLookupFlags(ip, listings),
+		Flags:   ipLookupFlags(ip, listings),
-		VPNProviders: vpnProviders(listings),
+		IPLists: listings,
 		IPLists:      listings,
 	}
 }
 // vpnProviders returns the names of the VPN lists among listings. It returns
 // an empty list, never nil, so that an answer's vpn_providers is [] rather
 // than null.
 func vpnProviders(listings []iplist.Listing) []string {
 	names := []string{}
 	for _, listing := range listings {
 		if listing.VPN {
 			names = append(names, listing.Name)
 		}
 	}
 	return names
 }
 // ipListListings returns the IP lists that contain ip. It returns an empty
 // list, never nil, so that an answer's ip_lists is [] rather than null.
 func (s *Server) ipListListings(ip string) []iplist.Listing {
@@ -1022,9 +999,6 @@ func ipLookupFlags(ip string, listings []iplist.Listing) IPLookupFlags {
 		IsTor: slices.ContainsFunc(listings, func(l iplist.Listing) bool {
 			return l.Name == iplist.TorExitsList
 		}),
 		IsVPN: slices.ContainsFunc(listings, func(l iplist.Listing) bool {
 			return l.VPN
 		}),
 		IsBogon: isBogon(ip),
 	}
 }
@@ -17,7 +17,6 @@ import (
 	"strings"
 	"sync/atomic"
 	"testing"
 	"testing/synctest"
 	"time"
 	"git.eeqj.de/sneak/routewatch/internal/config"
@@ -175,9 +174,6 @@ type tableStats struct {
 // carried 203.0.113.0/24, the two with kept routes withdrew it, so its origin
 // keeps no route. The oldest and newest routes are those of the other two
 // prefixes.
 //
 // The requests run in a synctest bubble, whose clock is fake, so a stall on
 // the host does not use up the handlers' 4-second limit.
 func TestStatsHandlersAnswerFromMemory(t *testing.T) {
 	t.Parallel()
@@ -223,11 +219,7 @@ func TestStatsHandlersAnswerFromMemory(t *testing.T) {
 	for name, handler := range handlers {
 		rec := httptest.NewRecorder()
-
+		handler(rec, httptest.NewRequestWithContext(t.Context(), http.MethodGet, "/", nil))
 		synctest.Test(t, func(t *testing.T) {
 			handler(rec,
 				httptest.NewRequestWithContext(t.Context(), http.MethodGet, "/", nil))
 		})
 		if rec.Code != http.StatusOK {
 			t.Errorf("%s: status %d, want %d; body %s",
@@ -262,20 +254,15 @@ func TestStatsHandlersAnswerFromMemory(t *testing.T) {
 // TestStatsAnswerCarriesChurnPerMinute checks that the stream object of the
 // /api/v1/stats answer holds route_churn_per_min as a whole number, and no
 // longer route_churn_per_sec, the moving average it replaces
-// (https://git.eeqj.de/sneak/routewatch/issues/160). The request runs in a
+// (https://git.eeqj.de/sneak/routewatch/issues/160).
 // synctest bubble, whose clock is fake, so a stall on the host does not use up
 // the handler's 4-second limit.
 func TestStatsAnswerCarriesChurnPerMinute(t *testing.T) {
 	t.Parallel()
 	s := newServerWithTestRoutes(t)
 	rec := httptest.NewRecorder()
-
+	s.handleStats()(rec,
-	synctest.Test(t, func(t *testing.T) {
+		httptest.NewRequestWithContext(t.Context(), http.MethodGet, statsPath, nil))
 		s.handleStats()(rec,
 			httptest.NewRequestWithContext(t.Context(), http.MethodGet, statsPath, nil))
 	})
 	if rec.Code != http.StatusOK {
 		t.Fatalf("status %d, want %d; body %s", rec.Code, http.StatusOK, rec.Body)
@@ -323,26 +310,18 @@ func (heldBackHandler) HeldBackCount() int                 { return heldBackMess
 // TestStatsAnswerGivesHowManyMessagesAHandlerHoldsBack registers a handler
 // that holds back messages. Its figures in /api/v1/stats, which the status
-// page shows, must give how many. The request runs in a synctest bubble, whose
+// page shows, must give how many.
 // clock is fake, so a stall on the host does not use up the handler's 4-second
 // limit.
 func TestStatsAnswerGivesHowManyMessagesAHandlerHoldsBack(t *testing.T) {
 	t.Parallel()
 	s := newServerWithTestRoutes(t)
 	s.streamer.RegisterHandler(heldBackHandler{})
 	var answer []byte
 	synctest.Test(t, func(t *testing.T) {
 		answer = get(t, s, statsPath).Body.Bytes()
 	})
 	var body struct {
 		Data StatsResponse `json:"data"`
 	}
-	err := json.Unmarshal(answer, &body)
+	err := json.Unmarshal(get(t, s, statsPath).Body.Bytes(), &body)
 	if err != nil {
 		t.Fatalf("decoding the answer: %v", err)
 	}
@@ -386,9 +365,7 @@ type unitStats struct {
 // names. They used to be strings with the unit in them, such as "1h18m34s" or
 // "1.1 GB" (https://git.eeqj.de/sneak/routewatch/issues/199). The stream has
 // never connected, so the uptime is 0. The memory use in /api/v1/stats is the
-// same number of bytes as its gc.heap_alloc_bytes. The requests run in a
+// same number of bytes as its gc.heap_alloc_bytes.
 // synctest bubble, whose clock is fake, so a stall on the host does not use up
 // the handlers' 4-second limit.
 func TestStatsAnswersGiveUnitsInFieldNames(t *testing.T) {
 	t.Parallel()
@@ -398,11 +375,7 @@ func TestStatsAnswersGiveUnitsInFieldNames(t *testing.T) {
 	s.SetASNFetcher(fixedIntervalASNFetcher{interval: fetchInterval})
 	for _, path := range []string{statusJSONPath, statsPath} {
-		var answer []byte
+		answer := get(t, s, path).Body.Bytes()
 		synctest.Test(t, func(t *testing.T) {
 			answer = get(t, s, path).Body.Bytes()
 		})
 		var body struct {
 			Data unitStats `json:"data"`
@@ -443,89 +416,82 @@ func TestStatsAnswersGiveUnitsInFieldNames(t *testing.T) {
 // connection_duration_seconds of /api/v1/stats is null while the stream is not
 // connected, and a whole number of seconds once it is. It used to be the
 // string "disconnected", or a Go duration such as "1h18m34s"
-// (https://git.eeqj.de/sneak/routewatch/issues/199). The test runs in a
+// (https://git.eeqj.de/sneak/routewatch/issues/199).
 // synctest bubble, whose clock is fake, so a stall on the host does not use up
 // the handler's 4-second limit.
 func TestStatsAnswerGivesConnectionDurationInSeconds(t *testing.T) {
 	t.Parallel()
 	s := newServerWithTestRoutes(t)
-	synctest.Test(t, func(t *testing.T) {
+	connectionDuration := func() json.RawMessage {
-		connectionDuration := func() json.RawMessage {
+		answer := get(t, s, statsPath).Body.Bytes()
 			answer := get(t, s, statsPath).Body.Bytes()
-			var body struct {
+		var body struct {
-				Data map[string]json.RawMessage `json:"data"`
+			Data map[string]json.RawMessage `json:"data"`
 			}
 			err := json.Unmarshal(answer, &body)
 			if err != nil {
 				t.Fatalf("decoding the answer: %v; answer %s", err, answer)
 			}
 			duration, ok := body.Data["connection_duration_seconds"]
 			if !ok {
 				t.Fatalf("no connection_duration_seconds: %s", answer)
 			}
 			return duration
 		}
-		disconnected := connectionDuration()
+		err := json.Unmarshal(answer, &body)
-		if string(disconnected) != "null" {
+		if err != nil {
-			t.Errorf("disconnected: connection_duration_seconds = %s, want null",
+			t.Fatalf("decoding the answer: %v; answer %s", err, answer)
 				disconnected)
 		}
-		s.streamer.GetMetricsTracker().SetConnected(true)
+		duration, ok := body.Data["connection_duration_seconds"]
-
+		if !ok {
-		var seconds int64
+			t.Fatalf("no connection_duration_seconds: %s", answer)
 		connected := connectionDuration()
 		err := json.Unmarshal(connected, &seconds)
 		if err != nil || seconds != 0 {
 			t.Errorf("just connected: connection_duration_seconds = %s, want 0",
 				connected)
 		}
-	})
+
 		return duration
 	}
 	disconnected := connectionDuration()
 	if string(disconnected) != "null" {
 		t.Errorf("disconnected: connection_duration_seconds = %s, want null",
 			disconnected)
 	}
 	s.streamer.GetMetricsTracker().SetConnected(true)
 	var seconds int64
 	connected := connectionDuration()
 	err := json.Unmarshal(connected, &seconds)
 	if err != nil || seconds != 0 {
 		t.Errorf("just connected: connection_duration_seconds = %s, want 0",
 			connected)
 	}
 }
 // TestStreamDurationsCountSeconds checks that the uptime and the connection
 // duration of a stream that connected 90 seconds ago are both 90. A stream
 // that has never connected has an uptime of 0, and one that is not connected
-// has no connection duration. The test runs in a synctest bubble, whose clock
+// has no connection duration.
 // is fake, so a stall on the host does not add to the 90 seconds.
 func TestStreamDurationsCountSeconds(t *testing.T) {
 	t.Parallel()
-	synctest.Test(t, func(t *testing.T) {
+	const connectedFor = 90 * time.Second
 		const connectedFor = 90 * time.Second
-		connectedSince := time.Now().Add(-connectedFor)
+	connectedSince := time.Now().Add(-connectedFor)
-		want := int64(connectedFor / time.Second)
+	want := int64(connectedFor / time.Second)
-		if got := uptimeSeconds(connectedSince); got != want {
+	if got := uptimeSeconds(connectedSince); got != want {
-			t.Errorf("uptimeSeconds = %d, want %d", got, want)
+		t.Errorf("uptimeSeconds = %d, want %d", got, want)
-		}
+	}
-		if got := uptimeSeconds(time.Time{}); got != 0 {
+	if got := uptimeSeconds(time.Time{}); got != 0 {
-			t.Errorf("uptimeSeconds before any connection = %d, want 0", got)
+		t.Errorf("uptimeSeconds before any connection = %d, want 0", got)
-		}
+	}
-		switch got := connectionDurationSeconds(true, connectedSince); {
+	switch got := connectionDurationSeconds(true, connectedSince); {
-		case got == nil:
+	case got == nil:
-			t.Errorf("connectionDurationSeconds = nil, want %d", want)
+		t.Errorf("connectionDurationSeconds = nil, want %d", want)
-		case *got != want:
+	case *got != want:
-			t.Errorf("connectionDurationSeconds = %d, want %d", *got, want)
+		t.Errorf("connectionDurationSeconds = %d, want %d", *got, want)
-		}
+	}
-		if got := connectionDurationSeconds(false, connectedSince); got != nil {
+	if got := connectionDurationSeconds(false, connectedSince); got != nil {
-			t.Errorf("connectionDurationSeconds while not connected = %d, want nil",
+		t.Errorf("connectionDurationSeconds while not connected = %d, want nil",
-				*got)
+			*got)
-		}
+	}
 	})
 }
 // newTestTable returns a routing table that holds a route for testPrefixV4,
@@ -1172,9 +1138,7 @@ func (failingDB) GetPrefixFirstSeen(
 // with the driver's error text. It also sends a prefix that does not parse.
 // No answer may carry the driver's or the prefix parser's text. Before the fix
 // the answers sent it to the client
-// (https://git.eeqj.de/sneak/routewatch/issues/108). The requests run in a
+// (https://git.eeqj.de/sneak/routewatch/issues/108).
 // synctest bubble, whose clock is fake, so a stall on the host does not use up
 // the stats handlers' 4-second limit.
 func TestJSONRoutesDoNotSendErrorDetails(t *testing.T) {
 	t.Parallel()
@@ -1195,11 +1159,8 @@ func TestJSONRoutesDoNotSendErrorDetails(t *testing.T) {
 	for _, tt := range tests {
 		rec := httptest.NewRecorder()
-
+		s.router.ServeHTTP(rec, httptest.NewRequestWithContext(
-		synctest.Test(t, func(t *testing.T) {
+			t.Context(), http.MethodGet, tt.path, nil))
 			s.router.ServeHTTP(rec, httptest.NewRequestWithContext(
 				t.Context(), http.MethodGet, tt.path, nil))
 		})
 		if rec.Code != tt.wantCode {
 			t.Errorf("%s: status %d, want %d; body %s",
@@ -1453,11 +1414,8 @@ func TestIPLookupKeepsRouteWhenPTRLookupDoesNotAnswer(t *testing.T) {
 	s := newServerWithTestRoutes(t)
 	useFakeResolver(s, &fakeResolver{ptrNeverAnswers: true})
-	// The request's time limit passes well after the PTR lookup's, so that a
+	// The request's time limit passes after the PTR lookup's.
-	// stall on a busy host does not use up the difference.
+	ctx, cancel := context.WithTimeout(t.Context(), 2*ptr.LookupTimeout)
 	const requestTimeLimit = ptr.LookupTimeout + 15*time.Second
 	ctx, cancel := context.WithTimeout(t.Context(), requestTimeLimit)
 	defer cancel()
 	rec := httptest.NewRecorder()
@@ -1504,19 +1462,8 @@ const listedUnroutedAddr = "203.0.113.1"
 // torExitAddr is the address that fakeIPLists lists on the Tor exit list.
 const torExitAddr = "203.0.113.2"
-// The addresses that fakeIPLists lists on one and on two VPN lists, and the
+// fakeIPLists has two lists. The test list holds addrInTestPrefixV4 and
-// names of those lists.
+// listedUnroutedAddr, and the Tor exit list holds torExitAddr.
 const (
 	oneVPNListAddr  = "203.0.113.3"
 	twoVPNListsAddr = "203.0.113.4"
 	testVPNList     = "test_vpn"
 	otherTestVPN    = "other_test_vpn"
 )
 // fakeIPLists has four lists. The test list holds addrInTestPrefixV4,
 // listedUnroutedAddr and twoVPNListsAddr. The Tor exit list holds torExitAddr.
 // The test VPN list holds oneVPNListAddr and twoVPNListsAddr, and the other
 // test VPN list holds twoVPNListsAddr.
 type fakeIPLists struct{}
 func testListing() iplist.Listing {
@@ -1537,18 +1484,6 @@ func (fakeIPLists) Lookup(addr netip.Addr) []iplist.Listing {
 		return []iplist.Listing{{Name: iplist.TorExitsList}}
 	}
 	if addr == netip.MustParseAddr(oneVPNListAddr) {
 		return []iplist.Listing{{Name: testVPNList, VPN: true}}
 	}
 	if addr == netip.MustParseAddr(twoVPNListsAddr) {
 		return []iplist.Listing{
 			{Name: otherTestVPN, VPN: true},
 			testListing(),
 			{Name: testVPNList, VPN: true},
 		}
 	}
 	return []iplist.Listing{}
 }
@@ -1557,7 +1492,7 @@ func (fakeIPLists) ShortestInterval() time.Duration {
 }
 // TestIPLookupFlags looks up addresses with and without a route. Every result
-// has every flag, under the JSON keys the API documents.
+// has both flags, under the JSON keys the API documents.
 func TestIPLookupFlags(t *testing.T) {
 	t.Parallel()
@@ -1603,9 +1538,7 @@ func TestIPLookupFlags(t *testing.T) {
 				t.Fatalf("%s: decoding flags %s: %v", path, results[0]["flags"], err)
 			}
-			want := map[string]bool{
+			want := map[string]bool{"is_tor": tt.tor, "is_bogon": tt.bogon}
 				"is_tor": tt.tor, "is_vpn": false, "is_bogon": tt.bogon,
 			}
 			if !maps.Equal(got, want) {
 				t.Errorf("%s: flags %v, want %v", path, got, want)
 			}
@@ -1613,61 +1546,6 @@ func TestIPLookupFlags(t *testing.T) {
 	}
 }
 // TestIPLookupReportsVPNProviders looks up addresses on no list, on a list
 // that is not a VPN list, on one VPN list and on two. is_vpn says whether any
 // VPN list holds the address, and vpn_providers names only those lists. An
 // address on none has [], not null.
 func TestIPLookupReportsVPNProviders(t *testing.T) {
 	t.Parallel()
 	s := newServerWithTestRoutes(t)
 	s.resolver = &fakeResolver{}
 	s.SetIPLists(fakeIPLists{})
 	tests := []struct {
 		name      string
 		addr      string
 		isVPN     string
 		providers string
 	}{
 		{"on no list", "1.1.1.1", "false", `[]`},
 		{"on a list that is not a VPN list", listedUnroutedAddr, "false", `[]`},
 		{"on one VPN list", oneVPNListAddr, "true", `["` + testVPNList + `"]`},
 		{
 			"on two VPN lists", twoVPNListsAddr, "true",
 			`["` + otherTestVPN + `","` + testVPNList + `"]`,
 		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
 			path := "/api/v1/ip/" + tt.addr
 			results := resultFields(t, get(t, s, path).Body.Bytes())
 			if len(results) != 1 {
 				t.Fatalf("%s: %d results, want 1", path, len(results))
 			}
 			var flags map[string]json.RawMessage
 			err := json.Unmarshal(results[0]["flags"], &flags)
 			if err != nil {
 				t.Fatalf("%s: decoding flags %s: %v", path, results[0]["flags"], err)
 			}
 			if got := string(flags["is_vpn"]); got != tt.isVPN {
 				t.Errorf("%s: is_vpn %s, want %s", path, got, tt.isVPN)
 			}
 			if got := string(results[0]["vpn_providers"]); got != tt.providers {
 				t.Errorf("%s: vpn_providers %s, want %s", path, got, tt.providers)
 			}
 		})
 	}
 }
 // TestIPLookupReportsIPLists looks up two routed addresses, one of them on an
 // IP list. The listed address's result names the list, says what it means and
 // when it was updated. The other's result has an empty list.
@@ -2456,13 +2334,9 @@ func settledGoroutineCount() int {
 	return prev
 }
-// waitForGoroutines waits up to 15 seconds for the goroutine count to drop to
+// waitForGoroutines waits until the goroutine count drops to target or below.
 // target or below.
 func waitForGoroutines(target int) bool {
-	const maxWait = 15 * time.Second
+	for range 100 {
 	deadline := time.Now().Add(maxWait)
 	for time.Now().Before(deadline) {
 		if runtime.NumGoroutine() <= target {
 			return true
 		}
@@ -76,9 +76,7 @@ func asLink(asn int) string {
 }
 // TestHomePageCardsShowTheTableFigures fills a routing table and the asns
-// table, works out the cards, and checks that each card shows its figure. The
+// table, works out the cards, and checks that each card shows its figure.
 // cards are worked out in a synctest bubble, whose clock is fake, so a stall on
 // the host does not use up the 4-second limit on their database read.
 func TestHomePageCardsShowTheTableFigures(t *testing.T) {
 	t.Parallel()
@@ -97,9 +95,7 @@ func TestHomePageCardsShowTheTableFigures(t *testing.T) {
 		t.Fatalf("GetOrCreateASNBatch: %v", err)
 	}
-	synctest.Test(t, func(t *testing.T) {
+	s.refreshHomeCards(t.Context())
 		s.refreshHomeCards(t.Context())
 	})
 	page := get(t, s, "/").Body.String()
@@ -283,7 +279,7 @@ func TestKeepHomeCardsFreshWorksThemOutEveryInterval(t *testing.T) {
 	const (
 		interval = 10 * time.Millisecond
-		maxWait  = 15 * time.Second
+		maxWait  = 5 * time.Second
 	)
 	table := emptyTable()
@@ -325,7 +321,7 @@ func TestKeepHomeCardsFreshWorksThemOutEveryInterval(t *testing.T) {
 func TestStartedServerWorksOutTheCards(t *testing.T) {
 	t.Parallel()
-	const maxWait = 15 * time.Second
+	const maxWait = 5 * time.Second
 	s := newServerWithTable(t, newCardsTable())
@@ -14,7 +14,6 @@ import (
 	"regexp"
 	"strings"
 	"testing"
 	"testing/synctest"
 	"time"
 	"git.eeqj.de/sneak/routewatch/internal/config"
@@ -164,10 +163,6 @@ func TestJSONAnswersPutNoUnitInAString(t *testing.T) {
 // router and the middleware write. Before the fix a panic in a handler, and a
 // method /status.json or the health check does not take, answered with an
 // empty body (https://git.eeqj.de/sneak/routewatch/issues/201).
 //
 // The requests run in a synctest bubble, whose clock is fake, so a stall on
 // the host does not use up the 2-second limit of the health check or the
 // 4-second limit of the stats handlers.
 func TestJSONAnswersCarryMeta(t *testing.T) {
 	t.Parallel()
@@ -186,10 +181,6 @@ func TestJSONAnswersCarryMeta(t *testing.T) {
 	s.router.Get(panicsPath, JSONValidationMiddleware(http.HandlerFunc(
 		func(http.ResponseWriter, *http.Request) { panic(errDiskIO) })).ServeHTTP)
 	failing := New(failingDB{}, newTestTable(),
 		streamer.New(logger.New(), metrics.New()), logger.New(), &config.Config{})
 	useFakeResolver(failing, &fakeResolver{})
 	tests := []struct {
 		method   string
 		path     string
@@ -225,40 +216,42 @@ func TestJSONAnswersCarryMeta(t *testing.T) {
 		{http.MethodGet, panicsPath, http.StatusInternalServerError},
 	}
-	synctest.Test(t, func(t *testing.T) {
+	for _, tt := range tests {
-		for _, tt := range tests {
+		checkAnswerCarriesMeta(t, s, httptest.NewRequestWithContext(
-			checkAnswerCarriesMeta(t, s, httptest.NewRequestWithContext(
+			t.Context(), tt.method, tt.path, nil), tt.wantCode)
-				t.Context(), tt.method, tt.path, nil), tt.wantCode)
+	}
 		}
-		// A request whose time limit has already passed answers 504. The
+	// A request whose time limit has already passed answers 504. The handlers
-		// handlers write the answers of the first five routes, and the JSON
+	// write the answers of the first five routes, and the JSON check on the
-		// check on the route writes the last.
+	// route writes the last.
-		pastTimeLimit, cancel := context.WithDeadline(t.Context(), time.Now())
+	pastTimeLimit, cancel := context.WithDeadline(t.Context(), time.Now())
-		defer cancel()
+	defer cancel()
-		for _, path := range []string{
+	for _, path := range []string{
-			statusJSONPath, statsPath, "/ip/" + addrInTestPrefixV4,
+		statusJSONPath, statsPath, "/ip/" + addrInTestPrefixV4,
-			"/api/v1/ip/" + addrInTestPrefixV4, asJSONPath, writesNothingPath,
+		"/api/v1/ip/" + addrInTestPrefixV4, asJSONPath, writesNothingPath,
-		} {
+	} {
-			checkAnswerCarriesMeta(t, s, httptest.NewRequestWithContext(
+		checkAnswerCarriesMeta(t, s, httptest.NewRequestWithContext(
-				pastTimeLimit, http.MethodGet, path, nil), http.StatusGatewayTimeout)
+			pastTimeLimit, http.MethodGet, path, nil), http.StatusGatewayTimeout)
-		}
+	}
-		// With a store whose reads fail, the health check answers 503, and
+	// With a store whose reads fail, the health check answers 503, and the
-		// the handlers of the other routes 500.
+	// handlers of the other routes 500.
 	failing := New(failingDB{}, newTestTable(),
 		streamer.New(logger.New(), metrics.New()), logger.New(), &config.Config{})
 	useFakeResolver(failing, &fakeResolver{})
 	checkAnswerCarriesMeta(t, failing, httptest.NewRequestWithContext(
 		t.Context(), http.MethodGet, healthCheckPath, nil),
 		http.StatusServiceUnavailable)
 	for _, path := range []string{
 		statusJSONPath, statsPath, asJSONPath,
 		"/api/v1/ip/" + addrInTestPrefixV4, "/ip/" + addrInTestPrefixV4,
 	} {
 		checkAnswerCarriesMeta(t, failing, httptest.NewRequestWithContext(
-			t.Context(), http.MethodGet, healthCheckPath, nil),
+			t.Context(), http.MethodGet, path, nil), http.StatusInternalServerError)
-			http.StatusServiceUnavailable)
+	}
 		for _, path := range []string{
 			statusJSONPath, statsPath, asJSONPath,
 			"/api/v1/ip/" + addrInTestPrefixV4, "/ip/" + addrInTestPrefixV4,
 		} {
 			checkAnswerCarriesMeta(t, failing, httptest.NewRequestWithContext(
 				t.Context(), http.MethodGet, path, nil), http.StatusInternalServerError)
 		}
 	})
 }
 // checkAnswerCarriesMeta serves req through the server's router, and checks
@@ -5,7 +5,6 @@ import (
 	"net/http"
 	"net/http/httptest"
 	"testing"
 	"testing/synctest"
 )
 // TestRoutesAnswerHEAD sends HEAD for a page and JSON routes through the
@@ -13,23 +12,15 @@ import (
 // lookup of the caller's own address, are in the list because chi's GetHead
 // does not reach them. Before the fix every route answered HEAD with 405
 // (https://git.eeqj.de/sneak/routewatch/issues/111).
 //
 // The requests run in a synctest bubble, whose clock is fake, so a stall on
 // the host does not use up the stats handlers' 4-second limit. The resolver
 // is fake because no time limit would cut off a real DNS lookup in a bubble.
 func TestRoutesAnswerHEAD(t *testing.T) {
 	t.Parallel()
 	s := newServerWithTestRoutes(t)
 	s.resolver = &fakeResolver{}
 	for _, path := range []string{"/", statusJSONPath, statsPath, "/ip", "/ip/"} {
 		rec := httptest.NewRecorder()
-
+		s.router.ServeHTTP(rec, httptest.NewRequestWithContext(
-		synctest.Test(t, func(t *testing.T) {
+			t.Context(), http.MethodHead, path, nil))
 			s.router.ServeHTTP(rec, httptest.NewRequestWithContext(
 				t.Context(), http.MethodHead, path, nil))
 		})
 		if rec.Code != http.StatusOK {
 			t.Errorf("HEAD %s: status %d, want %d; body %s",
@@ -22,10 +22,10 @@ func TestStopClosesTheConnectionOfARequestStillRunning(t *testing.T) {
 		stopDeadline = 100 * time.Millisecond
 		// waitTimeout is how long the test waits for the request to reach
 		// the handler, and then for the client to see its connection closed.
-		waitTimeout = 15 * time.Second
+		waitTimeout = 2 * time.Second
 		// readHeaderTimeout bounds the test server's read of the request
 		// header, as every http.Server must.
-		readHeaderTimeout = waitTimeout
+		readHeaderTimeout = time.Second
 	)
 	release := make(chan struct{})
@@ -14,7 +14,6 @@ import (
 	"strings"
 	"sync/atomic"
 	"testing"
 	"testing/synctest"
 	"time"
 	"git.eeqj.de/sneak/routewatch/internal/logger"
@@ -399,7 +398,7 @@ func TestStopQueuesTheHeldStateMessages(t *testing.T) {
 	const (
 		held    = 2
 		lines   = held + 1
-		maxWait = 15 * time.Second
+		maxWait = 5 * time.Second
 	)
 	srv := httptest.NewServer(http.HandlerFunc(
@@ -479,15 +478,15 @@ func TestStopQueuesTheHeldStateMessages(t *testing.T) {
 // TestStopReturnsByItsDeadline stops a streamer whose handler has a full queue
 // and a STATE message held for it, and a worker that stays busy until the test
 // ends, as one does whose handler waits for a database write. Stop must return
-// within its deadline plus a margin instead of waiting for room on the queue
+// within its deadline plus a small margin instead of waiting for room on the
-// and for the worker, and log as not handed over the held message and every
+// queue and for the worker, and log as not handed over the held message and
-// message on the queue.
+// every message on the queue.
 func TestStopReturnsByItsDeadline(t *testing.T) {
 	t.Parallel()
 	const (
 		deadline = 100 * time.Millisecond
-		margin   = 15 * time.Second
+		margin   = 2 * time.Second
 	)
 	var logs bytes.Buffer
@@ -578,7 +577,7 @@ func TestStopBeforeMessageReachesQueues(t *testing.T) {
 func TestReconnectWhenStreamEnds(t *testing.T) {
 	t.Parallel()
-	endResponse := pipeTransport{write: func(context.Context, io.Writer) {}}
+	endResponse := func(http.ResponseWriter, *http.Request) {}
 	checkReconnect(t, endResponse, streamIdleTimeout)
 }
@@ -590,8 +589,9 @@ func TestReconnectWhenStreamGoesIdle(t *testing.T) {
 	const idleTimeout = 50 * time.Millisecond
-	holdResponse := pipeTransport{
+	holdResponse := func(w http.ResponseWriter, r *http.Request) {
-		write: func(ctx context.Context, _ io.Writer) { <-ctx.Done() },
+		flush(w)
 		<-r.Context().Done()
 	}
 	checkReconnect(t, holdResponse, idleTimeout)
 }
@@ -604,51 +604,16 @@ func TestReconnectWhenServerNeverAnswers(t *testing.T) {
 	const idleTimeout = 50 * time.Millisecond
-	neverAnswer := roundTripFunc(
+	neverAnswer := func(_ http.ResponseWriter, r *http.Request) {
-		func(req *http.Request) (*http.Response, error) {
+		<-r.Context().Done()
-			<-req.Context().Done()
+	}
 			return nil, req.Context().Err()
 		},
 	)
 	checkReconnect(t, neverAnswer, idleTimeout)
 }
-// pipeTransport answers every request with a response whose body write fills.
+// TestStreamNotDroppedWhileLinesArrive has the server send lines well within
-// The body fails when the request's context ends, as a connection's does.
+// the idle timeout for several times the timeout, then end the response. Each
-// write gets that context, so that it can end when the request does.
+// line must start the idle timeout over, so the stream lasts until the server
-type pipeTransport struct {
+// ends it instead of being dropped as idle.
 	write func(context.Context, io.Writer)
 }
 func (p pipeTransport) RoundTrip(req *http.Request) (*http.Response, error) {
 	body, w := io.Pipe()
 	context.AfterFunc(req.Context(), func() {
 		_ = w.CloseWithError(req.Context().Err())
 	})
 	go func(ctx context.Context) {
 		p.write(ctx, w)
 		_ = w.Close()
 	}(req.Context())
 	return &http.Response{StatusCode: http.StatusOK, Body: body}, nil
 }
 // roundTripFunc makes a function an http.RoundTripper.
 type roundTripFunc func(*http.Request) (*http.Response, error)
 func (f roundTripFunc) RoundTrip(req *http.Request) (*http.Response, error) {
 	return f(req)
 }
 // TestStreamNotDroppedWhileLinesArrive has a response send lines well within
 // the idle timeout for several times the timeout, then end. Each line must
 // start the idle timeout over, so the stream lasts until the response ends
 // instead of being dropped as idle. It runs in a synctest bubble, whose clock
 // is fake, so a stall on the host does not use up the timeout.
 func TestStreamNotDroppedWhileLinesArrive(t *testing.T) {
 	t.Parallel()
@@ -658,35 +623,26 @@ func TestStreamNotDroppedWhileLinesArrive(t *testing.T) {
 		sendFor      = 5 * idleTimeout
 	)
-	// The streamer is made outside the bubble. Its metrics start a goroutine
+	srv := httptest.NewServer(http.HandlerFunc(
-	// that never returns, and a bubble waits for each of its goroutines to
+		func(w http.ResponseWriter, _ *http.Request) {
 	// return.
 	s := New(logger.New(), metrics.New())
 	s.idleTimeout = idleTimeout
 	s.client = &http.Client{Transport: pipeTransport{
 		write: func(ctx context.Context, w io.Writer) {
 			deadline := time.Now().Add(sendFor)
 			for time.Now().Before(deadline) {
 				_, _ = io.WriteString(w, updateLine)
-				// The wait ends with the stream. A bubble's clock stops when
+				flush(w)
-				// the test function returns, and a goroutine then still
+				time.Sleep(lineInterval)
 				// asleep panics the test binary.
 				select {
 				case <-ctx.Done():
 					return
 				case <-time.After(lineInterval):
 				}
 			}
-		},
+		}))
-	}}
+	defer srv.Close()
-	synctest.Test(t, func(t *testing.T) {
+	s := New(logger.New(), metrics.New())
-		err := s.stream(context.Background())
+	s.url = srv.URL
-		if !errors.Is(err, errStreamEnded) {
+	s.idleTimeout = idleTimeout
-			t.Fatalf("stream returned %v, want %v", err, errStreamEnded)
+
-		}
+	err := s.stream(context.Background())
-	})
+	if !errors.Is(err, errStreamEnded) {
 		t.Fatalf("stream returned %v, want %v", err, errStreamEnded)
 	}
 }
 // TestStreamReadsLongLine has the server send one UPDATE line of about
@@ -750,7 +706,7 @@ func TestHandlerStatsReadWhileMessagesAreDropped(t *testing.T) {
 	const (
 		lines       = 5
 		wantDropped = lines - 2
-		maxWait     = 15 * time.Second
+		maxWait     = 5 * time.Second
 	)
 	srv := httptest.NewServer(http.HandlerFunc(
@@ -864,70 +820,61 @@ func streamLines(t *testing.T, s *Streamer, lines string) {
 // line and then stays open. The streamer must come back for a second
 // response, must not be marked connected when it does, and must handle the
 // UPDATE in it.
 //
 // It runs in a synctest bubble, whose clock is fake, so a stall on the host
 // does not use up the idle timeout. The fake server gets the requests in the
 // order the streamer makes them, because no real connection carries them.
 func checkReconnect(
-	t *testing.T, firstResponse http.RoundTripper, idleTimeout time.Duration,
+	t *testing.T, firstResponse http.HandlerFunc, idleTimeout time.Duration,
 ) {
 	t.Helper()
-	const maxWait = 15 * time.Second
+	const maxWait = 5 * time.Second
 	// The tracker is made outside the bubble. It starts a goroutine that never
 	// returns, and a bubble waits for each of its goroutines to return.
 	tracker := metrics.New()
 	connectedAtReconnect := make(chan bool, 1)
-	synctest.Test(t, func(t *testing.T) {
+	var requests atomic.Int32
 		connectedAtReconnect := make(chan bool, 1)
 		laterResponse := pipeTransport{
 			write: func(ctx context.Context, w io.Writer) {
 				_, _ = io.WriteString(w, updateLine)
-				<-ctx.Done()
+	srv := httptest.NewServer(http.HandlerFunc(
-			},
+		func(w http.ResponseWriter, r *http.Request) {
-		}
+			if requests.Add(1) == 1 {
 				firstResponse(w, r)
-		var requests atomic.Int32
+				return
 			}
-		s := New(logger.New(), tracker)
+			select {
-		s.client = &http.Client{Transport: roundTripFunc(
+			case connectedAtReconnect <- tracker.IsConnected():
-			func(req *http.Request) (*http.Response, error) {
+			default:
-				if requests.Add(1) == 1 {
+			}
 					return firstResponse.RoundTrip(req)
 				}
-				select {
+			_, _ = io.WriteString(w, updateLine)
 				case connectedAtReconnect <- tracker.IsConnected():
 				default:
 				}
-				return laterResponse.RoundTrip(req)
+			flush(w)
-			},
+			<-r.Context().Done()
-		)}
+		}))
-		s.idleTimeout = idleTimeout
+	defer srv.Close()
 		s.minBackoff = time.Millisecond
 		handler := updateHandler{handled: make(chan struct{}, 1)}
 		s.RegisterHandler(handler)
-		err := s.Start(t.Context())
+	s := New(logger.New(), tracker)
-		if err != nil {
+	s.url = srv.URL
-			t.Fatalf("Start returned error: %v", err)
+	s.idleTimeout = idleTimeout
-		}
+	s.minBackoff = time.Millisecond
-		defer s.Stop(t.Context())
+	handler := updateHandler{handled: make(chan struct{}, 1)}
 	s.RegisterHandler(handler)
-		select {
+	err := s.Start(t.Context())
-		case <-handler.handled:
+	if err != nil {
-		case <-time.After(maxWait):
+		t.Fatalf("Start returned error: %v", err)
-			t.Fatalf("no message from a second response handled within %s", maxWait)
+	}
-		}
+	defer s.Stop(t.Context())
-		if <-connectedAtReconnect {
+	select {
-			t.Error("streamer was still marked connected when it came back " +
+	case <-handler.handled:
-				"for a second response")
+	case <-time.After(maxWait):
-		}
+		t.Fatalf("no message from a second response handled within %s", maxWait)
-	})
+	}
 	if <-connectedAtReconnect {
 		t.Error("streamer was still marked connected when it came back " +
 			"for a second response")
 	}
 }
 // settledGoroutineCount lets transient goroutines finish, then reports the
@@ -949,13 +896,9 @@ func settledGoroutineCount() int {
 	return prev
 }
-// waitForGoroutines waits up to 15 seconds for the goroutine count to drop to
+// waitForGoroutines waits until the goroutine count drops to target or below.
 // target or below.
 func waitForGoroutines(target int) bool {
-	const maxWait = 15 * time.Second
+	for range 100 {
 	deadline := time.Now().Add(maxWait)
 	for time.Now().Before(deadline) {
 		if runtime.NumGoroutine() <= target {
 			return true
 		}