From a7f9bebe6a8070442413c4ec24adaf40cbcd14d7 Mon Sep 17 00:00:00 2001
From: clawbot <sneak+clawbot@sneak.cloud>
Date: Tue, 27 Oct 2026 08:28:28 +0100
Subject: [PATCH] Run the internal/handlers tests in parallel (closes #194)

The handlers tests ran one at a time because config.New writes the
global viper instance. Each test spends most of its time in SQLite
under the race detector, so run in a row they took longer than the
20-second target.

Every test and subtest now calls t.Parallel(), as the ircserver and
db tests already do. A mutex in newTestServerWith makes tests start
their servers one at a time, since config.New writes viper and the
server reads it as it starts. No test is removed or otherwise
changed.

Model: opus-5-5
Co-authored-by: clawbot <sneak+clawbot@sneak.cloud>
---
 internal/handlers/api_test.go     | 278 +++++++++++++++++++++++++++++-
 internal/handlers/utility_test.go |  11 +-
 2 files changed, 284 insertions(+), 5 deletions(-)

diff --git a/internal/handlers/api_test.go b/internal/handlers/api_test.go
index 6ca6421..9201f1c 100644
--- a/internal/handlers/api_test.go
+++ b/internal/handlers/api_test.go
@@ -1,7 +1,3 @@
-// Tests use a global viper instance for configuration,
-// making parallel execution unsafe.
-//
-//nolint:paralleltest
 package handlers_test
 
 import (
@@ -143,6 +139,13 @@ type testServer struct {
 	handlers   *handlers.Handlers
 }
 
+// viperMu makes tests start their servers one at a time,
+// because config.New writes the global viper instance and
+// the server reads it as it starts.
+//
+//nolint:gochecknoglobals // guards a global, so must be one
+var viperMu sync.Mutex
+
 func newTestServer(
 	t *testing.T,
 ) *testServer {
@@ -158,6 +161,9 @@ func newTestServerWith(
 ) *testServer {
 	t.Helper()
 
+	viperMu.Lock()
+	defer viperMu.Unlock()
+
 	// A random name, so that no other test can share it, not
 	// even one that has finished but still holds its database
 	// open.
@@ -625,6 +631,8 @@ func findNumeric(
 // --- Tests ---
 
 func TestCreateSessionValid(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 	cookie := tserver.createSession("alice")
 
@@ -634,6 +642,8 @@ func TestCreateSessionValid(t *testing.T) {
 }
 
 func TestWelcomeNumeric(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 	token := tserver.createSession("welcomer")
 
@@ -648,6 +658,8 @@ func TestWelcomeNumeric(t *testing.T) {
 }
 
 func TestJoinNumerics(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 	token := tserver.createSession("jnumtest")
 
@@ -675,6 +687,8 @@ func TestJoinNumerics(t *testing.T) {
 }
 
 func TestCreateSessionDuplicate(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 	tserver.createSession("alice")
 
@@ -694,6 +708,8 @@ func TestCreateSessionDuplicate(t *testing.T) {
 // second test server leaves the first one's database alone and
 // starts on an empty one of its own.
 func TestEachTestServerHasItsOwnDatabase(t *testing.T) {
+	t.Parallel()
+
 	first := newTestServer(t)
 	first.createSession("samenick")
 
@@ -714,6 +730,8 @@ func TestEachTestServerHasItsOwnDatabase(t *testing.T) {
 }
 
 func TestCreateSessionEmpty(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 
 	resp := postSession(t, tserver, "")
@@ -728,6 +746,8 @@ func TestCreateSessionEmpty(t *testing.T) {
 }
 
 func TestCreateSessionInvalidChars(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 
 	resp := postSession(t, tserver, "hello world")
@@ -742,6 +762,8 @@ func TestCreateSessionInvalidChars(t *testing.T) {
 }
 
 func TestCreateSessionNumericStart(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 
 	resp := postSession(t, tserver, "123abc")
@@ -756,6 +778,8 @@ func TestCreateSessionNumericStart(t *testing.T) {
 }
 
 func TestCreateSessionMalformed(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 
 	resp, err := doRequest(
@@ -778,6 +802,8 @@ func TestCreateSessionMalformed(t *testing.T) {
 }
 
 func TestAuthNoCookie(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 
 	status, _ := tserver.getState("")
@@ -787,6 +813,8 @@ func TestAuthNoCookie(t *testing.T) {
 }
 
 func TestAuthBadCookie(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 
 	status, _ := tserver.getState(
@@ -798,6 +826,8 @@ func TestAuthBadCookie(t *testing.T) {
 }
 
 func TestAuthValidToken(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 	token := tserver.createSession("authtest")
 
@@ -815,6 +845,8 @@ func TestAuthValidToken(t *testing.T) {
 }
 
 func TestJoinChannel(t *testing.T) {
+	t.Parallel()
+
 	const channel = "#test"
 
 	tserver := newTestServer(t)
@@ -840,6 +872,8 @@ func TestJoinChannel(t *testing.T) {
 }
 
 func TestJoinWithoutHash(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 	token := tserver.createSession("joiner2")
 
@@ -864,6 +898,8 @@ func TestJoinWithoutHash(t *testing.T) {
 }
 
 func TestPartChannel(t *testing.T) {
+	t.Parallel()
+
 	const channel = "#test"
 
 	tserver := newTestServer(t)
@@ -896,6 +932,8 @@ func TestPartChannel(t *testing.T) {
 }
 
 func TestJoinMissingTo(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 	token := tserver.createSession("joiner3")
 
@@ -920,6 +958,8 @@ func TestJoinMissingTo(t *testing.T) {
 }
 
 func TestChannelMessage(t *testing.T) {
+	t.Parallel()
+
 	const channel = "#test"
 
 	tserver := newTestServer(t)
@@ -966,6 +1006,8 @@ func TestChannelMessage(t *testing.T) {
 }
 
 func TestMessageMissingBody(t *testing.T) {
+	t.Parallel()
+
 	const channel = "#test"
 
 	tserver := newTestServer(t)
@@ -995,6 +1037,8 @@ func TestMessageMissingBody(t *testing.T) {
 }
 
 func TestMessageMissingTo(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 	token := tserver.createSession("noto")
 
@@ -1019,6 +1063,8 @@ func TestMessageMissingTo(t *testing.T) {
 }
 
 func TestNonMemberCannotSend(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 	aliceToken := tserver.createSession("alice_nosend")
 	bobToken := tserver.createSession("bob_nosend")
@@ -1054,6 +1100,8 @@ func TestNonMemberCannotSend(t *testing.T) {
 }
 
 func TestDirectMessage(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 	aliceToken := tserver.createSession("alice_dm")
 	bobToken := tserver.createSession("bob_dm")
@@ -1095,6 +1143,8 @@ func TestDirectMessage(t *testing.T) {
 }
 
 func TestDMToNonexistentUser(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 	token := tserver.createSession("dmsender")
 
@@ -1120,6 +1170,8 @@ func TestDMToNonexistentUser(t *testing.T) {
 }
 
 func TestNickChange(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 	token := tserver.createSession("nick_test")
 
@@ -1144,6 +1196,8 @@ func TestNickChange(t *testing.T) {
 }
 
 func TestNickSameAsCurrent(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 	token := tserver.createSession("same_nick")
 
@@ -1157,6 +1211,8 @@ func TestNickSameAsCurrent(t *testing.T) {
 }
 
 func TestNickCollision(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 	token := tserver.createSession("nickuser")
 
@@ -1183,6 +1239,8 @@ func TestNickCollision(t *testing.T) {
 }
 
 func TestNickInvalid(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 	token := tserver.createSession("nickval")
 
@@ -1207,6 +1265,8 @@ func TestNickInvalid(t *testing.T) {
 }
 
 func TestNickEmptyBody(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 	token := tserver.createSession("nicknobody")
 
@@ -1230,6 +1290,8 @@ func TestNickEmptyBody(t *testing.T) {
 }
 
 func TestTopic(t *testing.T) {
+	t.Parallel()
+
 	const channel = "#topictest"
 
 	tserver := newTestServer(t)
@@ -1261,6 +1323,8 @@ func TestTopic(t *testing.T) {
 }
 
 func TestTopicMissingTo(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 	token := tserver.createSession("topicnoto")
 
@@ -1285,6 +1349,8 @@ func TestTopicMissingTo(t *testing.T) {
 }
 
 func TestTopicMissingBody(t *testing.T) {
+	t.Parallel()
+
 	const channel = "#topictest"
 
 	tserver := newTestServer(t)
@@ -1314,6 +1380,8 @@ func TestTopicMissingBody(t *testing.T) {
 }
 
 func TestTopicNonMember(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 	aliceToken := tserver.createSession("alice_topic")
 	bobToken := tserver.createSession("bob_topic")
@@ -1350,6 +1418,8 @@ func TestTopicNonMember(t *testing.T) {
 }
 
 func TestPing(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 	token := tserver.createSession("ping_user")
 
@@ -1369,6 +1439,8 @@ func TestPing(t *testing.T) {
 }
 
 func TestQuit(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 	token := tserver.createSession("quitter")
 	observerToken := tserver.createSession("observer")
@@ -1417,6 +1489,8 @@ const quitRaceTrials = 5
 // clients of a session log out at once, the session's QUIT
 // is sent once.
 func TestConcurrentLogoutsSendOneQuit(t *testing.T) {
+	t.Parallel()
+
 	checkQuitRace(t, func(tserver *testServer, tokens []string) {
 		tserver.postConcurrently(apiLogout, nil, tokens...)
 	})
@@ -1426,6 +1500,8 @@ func TestConcurrentLogoutsSendOneQuit(t *testing.T) {
 // clients of a session send QUIT at once, the session's
 // QUIT is sent once.
 func TestConcurrentQuitsSendOneQuit(t *testing.T) {
+	t.Parallel()
+
 	quit, err := json.Marshal(map[string]any{commandKey: irc.CmdQuit})
 	if err != nil {
 		t.Fatal(err)
@@ -1498,6 +1574,8 @@ func checkQuitRace(
 // its channel peer gets no QUIT, and that the other
 // client's logout then sends one QUIT.
 func TestLogoutOfOneClientKeepsSession(t *testing.T) {
+	t.Parallel()
+
 	const (
 		nick    = "twoclients"
 		channel = "#logouts"
@@ -1560,6 +1638,8 @@ func TestLogoutOfOneClientKeepsSession(t *testing.T) {
 // nothing: the client's token still works, the session is
 // still on its channel and its channel peer has no QUIT.
 func TestFailedLogoutChangesNothing(t *testing.T) {
+	t.Parallel()
+
 	const (
 		nick    = "stuckleaver"
 		channel = "#stuck"
@@ -1637,6 +1717,8 @@ const (
 // wakes the long poll of a user who shares a channel with
 // it.
 func TestQuitWakesPeerLongPoll(t *testing.T) {
+	t.Parallel()
+
 	const reason = "gone fishing"
 
 	checkQuitWakesPoll(t, reason, func(tserver *testServer, token string) {
@@ -1650,6 +1732,8 @@ func TestQuitWakesPeerLongPoll(t *testing.T) {
 // a session's last client wakes the long poll of a user who
 // shares a channel with it.
 func TestLastLogoutWakesPeerLongPoll(t *testing.T) {
+	t.Parallel()
+
 	checkQuitWakesPoll(t, "Connection closed", func(tserver *testServer, token string) {
 		tserver.logout(token)
 	})
@@ -1890,6 +1974,8 @@ func (tserver *testServer) postConcurrently(
 }
 
 func TestUnknownCommand(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 	token := tserver.createSession("cmdtest")
 
@@ -1913,6 +1999,8 @@ func TestUnknownCommand(t *testing.T) {
 }
 
 func TestEmptyCommand(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 	token := tserver.createSession("emptycmd")
 
@@ -1925,6 +2013,8 @@ func TestEmptyCommand(t *testing.T) {
 }
 
 func TestHistory(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 	token := tserver.createSession("historian")
 
@@ -1972,6 +2062,8 @@ func TestHistory(t *testing.T) {
 }
 
 func TestHistoryNonMember(t *testing.T) {
+	t.Parallel()
+
 	const channel = "#secret"
 
 	tserver := newTestServer(t)
@@ -2102,6 +2194,8 @@ func (tserver *testServer) getAllHistory(
 }
 
 func TestHistoryPaging(t *testing.T) {
+	t.Parallel()
+
 	const (
 		channel   = "#paging"
 		msgCount  = 5
@@ -2149,6 +2243,8 @@ func TestHistoryPaging(t *testing.T) {
 // and none sent to another session, and checks that the id
 // of a DM sent to another session is not accepted as before.
 func TestHistoryDMPaging(t *testing.T) {
+	t.Parallel()
+
 	const (
 		firstNick = "readerFirst"
 		laterNick = "readerLater"
@@ -2220,6 +2316,8 @@ func TestHistoryDMPaging(t *testing.T) {
 }
 
 func TestHistoryUnknownBefore(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 	token := tserver.createSession("lost")
 
@@ -2280,6 +2378,8 @@ func TestHistoryUnknownBefore(t *testing.T) {
 // released by QUIT does not get the DMs sent to its previous
 // holder.
 func TestHistoryReusedNick(t *testing.T) {
+	t.Parallel()
+
 	const victim = "victimV"
 
 	tserver := newTestServer(t)
@@ -2324,6 +2424,8 @@ func TestHistoryReusedNick(t *testing.T) {
 // again under the name of a deleted one starts with no
 // history, even when the old one had a key.
 func TestHistoryRecreatedChannel(t *testing.T) {
+	t.Parallel()
+
 	const channel = "#priv"
 
 	tserver := newTestServer(t)
@@ -2372,6 +2474,8 @@ func TestHistoryRecreatedChannel(t *testing.T) {
 }
 
 func TestChannelList(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 	token := tserver.createSession("lister")
 
@@ -2421,6 +2525,8 @@ func TestChannelList(t *testing.T) {
 }
 
 func TestChannelMembers(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 	token := tserver.createSession("membertest")
 
@@ -2451,6 +2557,8 @@ func TestChannelMembers(t *testing.T) {
 }
 
 func TestLongPoll(t *testing.T) {
+	t.Parallel()
+
 	const channel = "#longpoll"
 
 	tserver := newTestServer(t)
@@ -2518,6 +2626,8 @@ func TestLongPoll(t *testing.T) {
 }
 
 func TestLongPollTimeout(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 	token := tserver.createSession("lp_timeout")
 
@@ -2563,6 +2673,8 @@ func TestLongPollTimeout(t *testing.T) {
 // poll waits, is returned at once and not when the poll times
 // out, and that the poll then holds no broker wait channel.
 func TestLongPollReturnsMessageQueuedAfterFirstRead(t *testing.T) {
+	t.Parallel()
+
 	const (
 		nick   = "lp_late"
 		sender = "lp_late_sender"
@@ -2646,6 +2758,8 @@ var errReadFailed = errors.New("read failed")
 // whether it is answered at once, after its timeout, or with
 // an error because a read of the queue failed.
 func TestGetMessagesRemovesWaitChannel(t *testing.T) {
+	t.Parallel()
+
 	const (
 		// longTimeout, in seconds, is the timeout of the
 		// requests that must be answered without waiting.
@@ -2692,6 +2806,8 @@ func TestGetMessagesRemovesWaitChannel(t *testing.T) {
 
 	for _, tc := range tests {
 		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+
 			const nick = "wc_poller"
 
 			tserver := newTestServer(t)
@@ -2782,6 +2898,8 @@ func (tserver *testServer) getMessagesFailingRead(
 // a long poll whose client gives up while it waits leaves no
 // broker wait channel behind.
 func TestLongPollRemovesWaitChannelWhenClientGivesUp(t *testing.T) {
+	t.Parallel()
+
 	const (
 		nick = "wc_leaver"
 
@@ -2916,6 +3034,8 @@ func (tserver *testServer) queueMessage(
 }
 
 func TestEphemeralChannelCleanup(t *testing.T) {
+	t.Parallel()
+
 	const channel = "#ephemeral"
 
 	tserver := newTestServer(t)
@@ -2960,6 +3080,8 @@ func TestEphemeralChannelCleanup(t *testing.T) {
 }
 
 func TestConcurrentSessions(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 
 	var waitGroup sync.WaitGroup
@@ -3021,6 +3143,8 @@ func TestConcurrentSessions(t *testing.T) {
 }
 
 func TestServerInfo(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 
 	resp, err := doRequest(
@@ -3043,6 +3167,8 @@ func TestServerInfo(t *testing.T) {
 }
 
 func TestHealthcheck(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 
 	resp, err := doRequest(
@@ -3079,6 +3205,8 @@ func TestHealthcheck(t *testing.T) {
 }
 
 func TestHealthcheckRuntimeStatsFields(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 
 	resp, err := doRequest(
@@ -3122,6 +3250,8 @@ func TestHealthcheckRuntimeStatsFields(t *testing.T) {
 }
 
 func TestHealthcheckRuntimeStatsValues(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 
 	token := tserver.createSession("statsuser")
@@ -3240,6 +3370,8 @@ func postJSONExpectStatus(
 }
 
 func TestPassCommand(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 	token := tserver.createSession("passuser")
 
@@ -3279,6 +3411,8 @@ const (
 // counts bytes: "é" is two bytes in UTF-8, so 72 of them are
 // refused.
 func TestPassCommandLength(t *testing.T) {
+	t.Parallel()
+
 	cases := []struct {
 		name     string
 		password string
@@ -3294,6 +3428,8 @@ func TestPassCommandLength(t *testing.T) {
 
 	for _, tc := range cases {
 		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+
 			tserver := newTestServer(t)
 			token := tserver.createSession("pwlength")
 
@@ -3338,6 +3474,8 @@ func TestPassCommandLength(t *testing.T) {
 }
 
 func TestPassCommandEmpty(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 	token := tserver.createSession("emptypw")
 
@@ -3364,6 +3502,8 @@ func TestPassCommandEmpty(t *testing.T) {
 }
 
 func TestLoginValid(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 
 	// Create session and set password via PASS command.
@@ -3432,6 +3572,8 @@ func TestLoginValid(t *testing.T) {
 }
 
 func TestLoginWrongPassword(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 
 	// Create session and set password via PASS command.
@@ -3453,6 +3595,8 @@ func TestLoginWrongPassword(t *testing.T) {
 }
 
 func TestLoginNonexistentUser(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 
 	postJSONExpectStatus(
@@ -3466,6 +3610,8 @@ func TestLoginNonexistentUser(t *testing.T) {
 }
 
 func TestSessionCookie(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 
 	body, err := json.Marshal(
@@ -3532,6 +3678,8 @@ func TestSessionCookie(t *testing.T) {
 }
 
 func TestSessionStillWorks(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 
 	// Verify anonymous session creation still works.
@@ -3599,6 +3747,8 @@ func getNumericParams(
 }
 
 func TestWhoisShowsHostInfo(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 
 	token := tserver.createSessionWithUsername(
@@ -3694,6 +3844,8 @@ func (tserver *testServer) createSessionWithUsername(
 }
 
 func TestWhoShowsHostInfo(t *testing.T) {
+	t.Parallel()
+
 	const channel = "#whotest"
 
 	tserver := newTestServer(t)
@@ -3759,6 +3911,8 @@ func assertWhoReplyUsername(
 }
 
 func TestSessionUsernameDefault(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 
 	// Create session without specifying username.
@@ -3805,6 +3959,8 @@ func TestSessionUsernameDefault(t *testing.T) {
 }
 
 func TestLoginRateLimitExceeded(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 
 	// Exhaust the burst (default: 5 per IP) using
@@ -3868,6 +4024,8 @@ func TestLoginRateLimitExceeded(t *testing.T) {
 }
 
 func TestLoginRateLimitAllowsNormalUse(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 
 	// Create session and set password via PASS command.
@@ -3908,6 +4066,8 @@ func TestLoginRateLimitAllowsNormalUse(t *testing.T) {
 }
 
 func TestNickBroadcastToChannels(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 	aliceToken := tserver.createSession("nick_a")
 	bobToken := tserver.createSession("nick_b")
@@ -3957,6 +4117,8 @@ func mintTestChannelHashcash(
 }
 
 func TestChannelHashcashSetMode(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 	token := tserver.createSession("hcmode_user")
 
@@ -3991,6 +4153,8 @@ func TestChannelHashcashSetMode(t *testing.T) {
 }
 
 func TestChannelHashcashQueryMode(t *testing.T) {
+	t.Parallel()
+
 	const channel = "#hcquery"
 
 	tserver := newTestServer(t)
@@ -4035,6 +4199,8 @@ func TestChannelHashcashQueryMode(t *testing.T) {
 }
 
 func TestChannelHashcashClearMode(t *testing.T) {
+	t.Parallel()
+
 	const channel = "#hcclear"
 
 	tserver := newTestServer(t)
@@ -4078,6 +4244,8 @@ func TestChannelHashcashClearMode(t *testing.T) {
 }
 
 func TestChannelHashcashRejectNoStamp(t *testing.T) {
+	t.Parallel()
+
 	const channel = "#hcreject"
 
 	tserver := newTestServer(t)
@@ -4121,6 +4289,8 @@ func TestChannelHashcashRejectNoStamp(t *testing.T) {
 }
 
 func TestChannelHashcashAcceptValidStamp(t *testing.T) {
+	t.Parallel()
+
 	const (
 		channel = "#hcaccept"
 		text    = "hello world"
@@ -4186,6 +4356,8 @@ func TestChannelHashcashAcceptValidStamp(t *testing.T) {
 }
 
 func TestChannelHashcashRejectReplayedStamp(t *testing.T) {
+	t.Parallel()
+
 	const (
 		channel = "#hcreplay"
 		text    = "unique msg"
@@ -4320,6 +4492,8 @@ func (tserver *testServer) sendConcurrently(
 // in several requests at once and checks that exactly one is
 // accepted and the other member receives exactly one copy.
 func TestChannelHashcashRejectConcurrentReplay(t *testing.T) {
+	t.Parallel()
+
 	const (
 		channel  = "#hcrace"
 		text     = "one stamp"
@@ -4395,6 +4569,8 @@ func TestChannelHashcashRejectConcurrentReplay(t *testing.T) {
 }
 
 func TestChannelHashcashNoRequirementWorks(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 	token := tserver.createSession("hcnone_user")
 
@@ -4423,6 +4599,8 @@ func TestChannelHashcashNoRequirementWorks(t *testing.T) {
 }
 
 func TestChannelHashcashInvalidBitsRange(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 	token := tserver.createSession("hcbits_user")
 
@@ -4450,6 +4628,8 @@ func TestChannelHashcashInvalidBitsRange(t *testing.T) {
 }
 
 func TestChannelHashcashMissingBitsArg(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 	token := tserver.createSession("hcnoarg_user")
 
@@ -4528,6 +4708,8 @@ func sessionCount(t *testing.T, tserver *testServer) int64 {
 // for its nick, and that no refused request creates a
 // session.
 func TestRefusedSessionLeavesStampUnspent(t *testing.T) {
+	t.Parallel()
+
 	const (
 		bits    = 2
 		badNick = "bad nick"
@@ -4592,6 +4774,8 @@ func TestRefusedSessionLeavesStampUnspent(t *testing.T) {
 }
 
 func TestNamesShowsHostmask(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 
 	queryToken, lastID := setupChannelWithIdentMember(
@@ -4613,6 +4797,8 @@ func TestNamesShowsHostmask(t *testing.T) {
 }
 
 func TestNamesOnJoinShowsHostmask(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 
 	// First user joins to populate the channel.
@@ -4739,6 +4925,8 @@ func newTestServerWithOper(
 }
 
 func TestOperCommandSuccess(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServerWithOper(t)
 
 	token := tserver.createSession("operuser")
@@ -4762,6 +4950,8 @@ func TestOperCommandSuccess(t *testing.T) {
 }
 
 func TestOperCommandFailure(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServerWithOper(t)
 
 	token := tserver.createSession("badoper")
@@ -4785,6 +4975,8 @@ func TestOperCommandFailure(t *testing.T) {
 }
 
 func TestOperCommandNeedMoreParams(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServerWithOper(t)
 
 	token := tserver.createSession("shortoper")
@@ -4808,6 +5000,8 @@ func TestOperCommandNeedMoreParams(t *testing.T) {
 }
 
 func TestOperWhoisShowsClientInfo(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServerWithOper(t)
 
 	// Create a target user.
@@ -4876,6 +5070,8 @@ func TestOperWhoisShowsClientInfo(t *testing.T) {
 }
 
 func TestNonOperWhoisHidesClientInfo(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServerWithOper(t)
 
 	// Create a target user.
@@ -4912,6 +5108,8 @@ func TestNonOperWhoisHidesClientInfo(t *testing.T) {
 }
 
 func TestWhoisShowsOperatorStatus(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServerWithOper(t)
 
 	// Create oper user and authenticate.
@@ -4951,6 +5149,8 @@ func TestWhoisShowsOperatorStatus(t *testing.T) {
 }
 
 func TestOperNoOlineConfigured(t *testing.T) {
+	t.Parallel()
+
 	// Standard test server has no oper configured.
 	tserver := newTestServer(t)
 
@@ -4981,6 +5181,8 @@ const kickCmd = "KICK"
 // TestOperatorAutoGrantOnCreate verifies that the first
 // user to join a channel (the creator) gets +o.
 func TestOperatorAutoGrantOnCreate(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 	token := tserver.createSession("creator")
 
@@ -5031,6 +5233,8 @@ func TestOperatorAutoGrantOnCreate(t *testing.T) {
 // TestSecondJoinerNotOperator verifies that subsequent
 // joiners do NOT get +o.
 func TestSecondJoinerNotOperator(t *testing.T) {
+	t.Parallel()
+
 	const channel = "#optest2"
 
 	tserver := newTestServer(t)
@@ -5085,6 +5289,8 @@ func TestSecondJoinerNotOperator(t *testing.T) {
 
 // TestModeGrantOperator tests MODE +o.
 func TestModeGrantOperator(t *testing.T) {
+	t.Parallel()
+
 	const channel = "#modeop"
 
 	tserver := newTestServer(t)
@@ -5148,6 +5354,8 @@ func TestModeGrantOperator(t *testing.T) {
 
 // TestModeRevokeOperator tests MODE -o.
 func TestModeRevokeOperator(t *testing.T) {
+	t.Parallel()
+
 	const channel = "#revoke"
 
 	tserver := newTestServer(t)
@@ -5202,6 +5410,8 @@ func TestModeRevokeOperator(t *testing.T) {
 
 // TestModeVoice tests MODE +v/-v.
 func TestModeVoice(t *testing.T) {
+	t.Parallel()
+
 	const channel = "#voice"
 
 	tserver := newTestServer(t)
@@ -5277,6 +5487,8 @@ func TestModeVoice(t *testing.T) {
 // TestModeNonOpCannotGrant verifies non-operators
 // cannot grant +o or +v.
 func TestModeNonOpCannotGrant(t *testing.T) {
+	t.Parallel()
+
 	const channel = "#noperm"
 
 	tserver := newTestServer(t)
@@ -5336,6 +5548,8 @@ func TestModeNonOpCannotGrant(t *testing.T) {
 
 // TestModeratedChannelBlocksNonVoiced tests +m mode.
 func TestModeratedChannelBlocksNonVoiced(t *testing.T) {
+	t.Parallel()
+
 	const channel = "#moderated"
 
 	tserver := newTestServer(t)
@@ -5379,6 +5593,8 @@ func TestModeratedChannelBlocksNonVoiced(t *testing.T) {
 // TestModeratedChannelAllowsOp tests that operators can
 // send in +m channels.
 func TestModeratedChannelAllowsOp(t *testing.T) {
+	t.Parallel()
+
 	const channel = "#modop"
 
 	tserver := newTestServer(t)
@@ -5426,6 +5642,8 @@ func TestModeratedChannelAllowsOp(t *testing.T) {
 // TestModeratedChannelAllowsVoiced tests that voiced
 // users can send in +m channels.
 func TestModeratedChannelAllowsVoiced(t *testing.T) {
+	t.Parallel()
+
 	const channel = "#modvoice"
 
 	tserver := newTestServer(t)
@@ -5479,6 +5697,8 @@ func TestModeratedChannelAllowsVoiced(t *testing.T) {
 
 // TestTopicLockDefaultOn verifies new channels have +t.
 func TestTopicLockDefaultOn(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 	token := tserver.createSession("topiclock")
 
@@ -5522,6 +5742,8 @@ func TestTopicLockDefaultOn(t *testing.T) {
 // TestTopicLockEnforced verifies non-operators cannot
 // change topic when +t is active.
 func TestTopicLockEnforced(t *testing.T) {
+	t.Parallel()
+
 	const channel = "#tlock"
 
 	tserver := newTestServer(t)
@@ -5558,6 +5780,8 @@ func TestTopicLockEnforced(t *testing.T) {
 // TestTopicLockOpCanChange verifies operators CAN change
 // topic when +t is active.
 func TestTopicLockOpCanChange(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 	opToken := tserver.createSession("topicop2")
 
@@ -5590,6 +5814,8 @@ func TestTopicLockOpCanChange(t *testing.T) {
 // TestTopicLockDisabled verifies that -t allows anyone
 // to change topic.
 func TestTopicLockDisabled(t *testing.T) {
+	t.Parallel()
+
 	const channel = "#tloff"
 
 	tserver := newTestServer(t)
@@ -5635,6 +5861,8 @@ func TestTopicLockDisabled(t *testing.T) {
 // TestKickByOperator tests that an operator can kick
 // a user.
 func TestKickByOperator(t *testing.T) {
+	t.Parallel()
+
 	const channel = "#kicktest"
 
 	tserver := newTestServer(t)
@@ -5692,6 +5920,8 @@ func TestKickByOperator(t *testing.T) {
 // TestKickByNonOperator tests that non-operators cannot
 // kick.
 func TestKickByNonOperator(t *testing.T) {
+	t.Parallel()
+
 	const channel = "#kickperm"
 
 	tserver := newTestServer(t)
@@ -5732,6 +5962,8 @@ func TestKickByNonOperator(t *testing.T) {
 // TestKickTargetNotInChannel tests kicking a user not
 // in the channel.
 func TestKickTargetNotInChannel(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 	opToken := tserver.createSession("op_kicknot")
 	_ = tserver.createSession("outsider")
@@ -5762,6 +5994,8 @@ func TestKickTargetNotInChannel(t *testing.T) {
 // TestKickBroadcastToChannel verifies the KICK message
 // is broadcast to all channel members.
 func TestKickBroadcastToChannel(t *testing.T) {
+	t.Parallel()
+
 	const channel = "#kickbc"
 
 	tserver := newTestServer(t)
@@ -5799,6 +6033,8 @@ func TestKickBroadcastToChannel(t *testing.T) {
 // TestNoticeNoAwayReply verifies NOTICE doesn't trigger
 // RPL_AWAY.
 func TestNoticeNoAwayReply(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 	senderToken := tserver.createSession("noticesend")
 	awayToken := tserver.createSession("noticeaway")
@@ -5832,6 +6068,8 @@ func TestNoticeNoAwayReply(t *testing.T) {
 // TestPrivmsgTriggersAway verifies PRIVMSG DOES trigger
 // RPL_AWAY.
 func TestPrivmsgTriggersAway(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 	senderToken := tserver.createSession("msgsend")
 	awayToken := tserver.createSession("msgaway")
@@ -5865,6 +6103,8 @@ func TestPrivmsgTriggersAway(t *testing.T) {
 // TestNoticeSkipsHashcash verifies NOTICE bypasses
 // hashcash on +H channels.
 func TestNoticeSkipsHashcash(t *testing.T) {
+	t.Parallel()
+
 	const channel = "#hcnotice"
 
 	tserver := newTestServer(t)
@@ -5903,6 +6143,8 @@ func TestNoticeSkipsHashcash(t *testing.T) {
 // TestModeratedNoticeBlocked verifies +m blocks NOTICE
 // from non-voiced/non-op users too.
 func TestModeratedNoticeBlocked(t *testing.T) {
+	t.Parallel()
+
 	const channel = "#modnotice"
 
 	tserver := newTestServer(t)
@@ -5943,6 +6185,8 @@ func TestModeratedNoticeBlocked(t *testing.T) {
 // TestNonOpCannotSetModerated verifies non-operators
 // cannot set +m.
 func TestNonOpCannotSetModerated(t *testing.T) {
+	t.Parallel()
+
 	const channel = "#modperm"
 
 	tserver := newTestServer(t)
@@ -5975,6 +6219,8 @@ func TestNonOpCannotSetModerated(t *testing.T) {
 
 // TestISupportPrefix verifies PREFIX=(ov)@+ is in 005.
 func TestISupportPrefix(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 	token := tserver.createSession("isupport")
 
@@ -6002,6 +6248,8 @@ func TestISupportPrefix(t *testing.T) {
 // TestModeQueryShowsModerated verifies MODE query shows
 // +m when set.
 func TestModeQueryShowsModerated(t *testing.T) {
+	t.Parallel()
+
 	const channel = "#mqtest"
 
 	tserver := newTestServer(t)
@@ -6043,6 +6291,8 @@ func TestModeQueryShowsModerated(t *testing.T) {
 // TestKickDefaultReason verifies KICK uses kicker's
 // nick as default reason.
 func TestKickDefaultReason(t *testing.T) {
+	t.Parallel()
+
 	const channel = "#kickdef"
 
 	tserver := newTestServer(t)
@@ -6084,6 +6334,8 @@ const (
 // TestBanAddRemoveList verifies +b add, list, and -b
 // remove via MODE commands.
 func TestBanAddRemoveList(t *testing.T) {
+	t.Parallel()
+
 	const channel = "#bans"
 
 	tserver := newTestServer(t)
@@ -6153,6 +6405,8 @@ func TestBanAddRemoveList(t *testing.T) {
 // TestBanBlocksJoin verifies that a banned user cannot
 // join a channel.
 func TestBanBlocksJoin(t *testing.T) {
+	t.Parallel()
+
 	const channel = "#banjoin"
 
 	tserver := newTestServer(t)
@@ -6186,6 +6440,8 @@ func TestBanBlocksJoin(t *testing.T) {
 // TestBanBlocksPrivmsg verifies that a banned user who
 // is already in a channel cannot send messages.
 func TestBanBlocksPrivmsg(t *testing.T) {
+	t.Parallel()
+
 	const channel = "#banmsg"
 
 	tserver := newTestServer(t)
@@ -6226,6 +6482,8 @@ func TestBanBlocksPrivmsg(t *testing.T) {
 // TestInviteOnlyJoin verifies +i behavior: join rejected
 // without invite, accepted with invite.
 func TestInviteOnlyJoin(t *testing.T) {
+	t.Parallel()
+
 	const channel = "#invonly"
 
 	tserver := newTestServer(t)
@@ -6279,6 +6537,8 @@ func TestInviteOnlyJoin(t *testing.T) {
 // TestSecretChannelHiddenFromList verifies +s hides a
 // channel from LIST for non-members.
 func TestSecretChannelHiddenFromList(t *testing.T) {
+	t.Parallel()
+
 	const channel = "#secret"
 
 	tserver := newTestServer(t)
@@ -6350,6 +6610,8 @@ func TestSecretChannelHiddenFromList(t *testing.T) {
 // TestChannelKeyJoin verifies +k behavior: wrong/missing
 // key is rejected, correct key allows join.
 func TestChannelKeyJoin(t *testing.T) {
+	t.Parallel()
+
 	const channel = "#keyed"
 
 	tserver := newTestServer(t)
@@ -6414,6 +6676,8 @@ func TestChannelKeyJoin(t *testing.T) {
 // TestUserLimitEnforcement verifies +l behavior: blocks
 // join when at capacity.
 func TestUserLimitEnforcement(t *testing.T) {
+	t.Parallel()
+
 	const channel = "#limited"
 
 	tserver := newTestServer(t)
@@ -6458,6 +6722,8 @@ func TestUserLimitEnforcement(t *testing.T) {
 // TestModeStringIncludesNewModes verifies that querying
 // channel mode returns the new modes (+i, +s, +k, +l).
 func TestModeStringIncludesNewModes(t *testing.T) {
+	t.Parallel()
+
 	const channel = "#modestr"
 
 	tserver := newTestServer(t)
@@ -6512,6 +6778,8 @@ func TestModeStringIncludesNewModes(t *testing.T) {
 // TestISUPPORT verifies the 005 numeric includes the
 // updated CHANMODES string.
 func TestISUPPORT(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 	token := tserver.createSession("isupport")
 
@@ -6538,6 +6806,8 @@ func TestISUPPORT(t *testing.T) {
 // TestNonOpCannotSetModes verifies non-operators
 // cannot set +i, +s, +k, +l, +b.
 func TestNonOpCannotSetModes(t *testing.T) {
+	t.Parallel()
+
 	const channel = "#noperm"
 
 	tserver := newTestServer(t)
diff --git a/internal/handlers/utility_test.go b/internal/handlers/utility_test.go
index f5dea41..adcc9b8 100644
--- a/internal/handlers/utility_test.go
+++ b/internal/handlers/utility_test.go
@@ -1,4 +1,3 @@
-//nolint:paralleltest // global viper, as in api_test.go
 package handlers_test
 
 import (
@@ -72,6 +71,8 @@ func numericBody(
 }
 
 func TestUserhost(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 
 	token := tserver.createSession("alice")
@@ -109,6 +110,8 @@ func TestUserhost(t *testing.T) {
 }
 
 func TestVersionAdminInfoTime(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServer(t)
 
 	token := tserver.createSession("frank")
@@ -147,6 +150,8 @@ func TestVersionAdminInfoTime(t *testing.T) {
 }
 
 func TestKill(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServerWithOper(t)
 
 	victimToken := tserver.createSession("victim")
@@ -213,6 +218,8 @@ func TestKill(t *testing.T) {
 }
 
 func TestWallops(t *testing.T) {
+	t.Parallel()
+
 	tserver := newTestServerWithOper(t)
 
 	receiverToken := tserver.createSession("receiver")
@@ -258,6 +265,8 @@ func TestWallops(t *testing.T) {
 }
 
 func TestUserMode(t *testing.T) {
+	t.Parallel()
+
 	const (
 		nick  = "alice"
 		other = "other"