Make backend tests wait on conditions instead of durations (#2190)

* Make backend tests wait on conditions instead of durations The backend workflow has a long tail of runs that fail once and pass on a rerun. Every one of them comes down to a test assuming an operation finishes within some duration rather than waiting for the state it needs. Three were reproducible and each was reproduced against the old code before being changed: TestServerAuthHooks minted a token that lived one second and never tested expiry, so a slow runner turned the first POST into a 401; TestServerApp_AnonMode saw "connection refused" because waitForHTTPServerStart returned silently after three seconds and left a later assertion to fail with something unrelated; TestFsStore_Cleanup slept 200ms against a 300ms ttl that Cleanup widens to 400ms with its commit grace, so roughly 100ms of stall collected an image meant to survive. Fixed sleeps before asserting on asynchronous work are replaced with polls on the condition itself, using require.Eventually and require.EventuallyWithT, and require.Never where the assertion is that something did not happen. Polling closures assert on the CollectT they are handed rather than on t, since testify runs them on another goroutine, and polls that issue HTTP requests stay under the rate limit on the routes they poll through. Where a test needs time to have passed, the clock input is pinned instead: staging ages are stamped with os.Chtimes on both sides of the cleanup boundary right before each call, which also makes the 100ms commit grace an exact case rather than something no assertion reaches, and the RSS tests set store.Comment.Timestamp explicitly rather than racing the wall clock into the first 100ms of a second so pubDate matches. chooseUnusedPort takes a port from the kernel's ephemeral range. Picking at random out of a fixed 10000-port window let two package binaries, which go test ./... runs concurrently, land on the same number between the probe closing and the server binding. The start helpers fail naming the port they waited on, and the SSL tests wait on the redirect port as well as the TLS one. Arbitrary budgets that nothing tests are gone: ten HTTP clients with a one-second timeout against bolt-backed import and export, the "should take about 100msec" assertions, and a one-second bound on noticing an already cancelled context. Shutdown stays bounded at ten seconds so a hang is still caught. Two assertions get stronger. TestServerAuthHooks accepted 403 or 401 from a blocked user, an alternative that existed only because the short token could expire mid-test; it is deterministically 403 now. TestAdmin_BlockedList asserted two users blocked while one carried the same 150ms ttl the next step waits to lapse, so the halves raced each other. goleak stops reporting the regexp2 clock goroutine, which chroma pulls in for syntax highlighting and which lives for up to a second after the last match with a timeout; it ends on its own but a binary finishing inside that window was reported as leaking, and this suite now finishes sooner. The ignore for net/http.(*Server).Shutdown goes the other way: it no longer matches anything, with both packages run fifteen times each under CPU oversubscription to confirm. Two gaps the change would otherwise have opened are covered directly rather than left to the side effects that used to cover them. The one-second token was the only thing exercising the authenticator's ClaimsUpd hook on refresh, so TestServerApp_ClaimsUpd now calls the hook itself and checks admin, blocked, email and restricted-name impersonation, including the two pass-through cases. Lifting the open-route limit removed the last incidental exercise of the rate limiter, so TestRateLimiter drives a burst past the allowance and checks the refusals and that the limit is per client. Both run without a wall clock, and both were confirmed to fail when the behaviour they cover is removed. Production code is untouched. The two sleeps outside test code, the 429 backoff in cmd/cleanup.go and the submit poll in store/image/image.go, are left alone: no CI failure implicates them. Test sleeps drop from 67 to 21, all of them either inside a testing/synctest bubble or a poll interval. The suite runs in about 22 seconds instead of 46, mostly because TestPublic_FindCommentsCtrl_ConsistentCount no longer paces a hundred subtests with an 80ms sleep each to stay under the open route limit. The 300s per-package budget now matches across both workflows, the race_test target and the documented command, and CLAUDE.md records the convention. with '#' will be ignored, and an empty message aborts the commit. # # Date: Sat Aug 22 01:12:31 2026 +0100 # # interactive rebase in progress; onto 7c312da1 # Last command done (1 command done): # reword deb6cbf1 # Make backend tests wait on conditions instead of durations # Next command to do (1 remaining command): # reword 262e6dc2 # Apply go fix under Go 1.27 # You are currently editing a commit while rebasing branch 'fix/backend-test-flakiness' on '7c312da1'. # # Changes to be committed: .github/workflows/release.yml # modified: CLAUDE.md # modified: Makefile modified: backend/_example/memory_store/server/rpc_test.go # modified: backend/app/cmd/import_test.go # modified: backend/app/cmd/server_test.go # modified: backend/app/main_test.go # modified: backend/app/rest/api/admin_test.go # modified: backend/app/rest/api/middleware_test.go # modified: backend/app/rest/api/migrator_test.go # modified: backend/app/rest/api/rest_private_test.go # modified: backend/app/rest/api/rest_public_test.go # modified: backend/app/rest/api/rest_test.go # modified: backend/app/rest/api/rss_test.go # modified: backend/app/rest/proxy/image_test.go # modified: backend/app/store/image/fs_store_test.go # modified: backend/app/store/service/service_test.go # modified: docs/backlog/api-tests-deadlock-on-macos.md # * Apply go fix under Go 1.27 Go 1.27 extends go fix with the modernizers, so `go fix ./...` now rewrites patterns the language has since replaced. Running it across all three modules produces this: legacy sync/atomic calls on plain integers become the atomic types (notify.Service.closed, image.Service.term and submitCount, and several test counters), reverse index loops become slices.Backward, a Split-then-index becomes strings.Cut, counted loops become range over an int, and interface{} becomes any in the e2e suite. The example module needed no changes. The e2e module is behind a build tag, so it only matches with `go fix -tags e2e ./...`. One knock-on: prealloc can see the bound of a loop once it is written as range over an int, so the slice it feeds is now preallocated. with '#' will be ignored, and an empty message aborts the commit. # # Date: Sat Aug 22 01:32:09 2026 +0100 # # interactive rebase in progress; onto 7c312da1 # Last commands done (2 commands done): # reword deb6cbf1 262e6dc2 # Apply go fix under Go 1.27 # No commands remaining. # You are currently editing a commit while rebasing branch 'fix/backend-test-flakiness' on '7c312da1'. # # Changes to be committed: backend/app/migrator/native.go # modified: backend/app/notify/notify.go backend/app/rest/api/rest_private_test.go # modified: backend/app/store/comment.go # modified: backend/app/store/image/image.go # modified: backend/app/store/service/service_test.go # modified: backend/app/store/service/title_test.go # modified: e2e/e2e_test.go # modified: e2e/widgets_test.go #
2026-08-21 22:17:44 -05:00
parent b6975af63c
commit 0b651dddd4
27 changed files with 676 additions and 404 deletions
@@ -62,7 +62,7 @@ func TestAdmin_Delete(t *testing.T) {
 		fmt.Sprintf("%s/api/v1/admin/comment/%s?site=remark42&url=https://radio-t.com/blah", ts.URL, id1), http.NoBody)
 	require.NoError(t, err)
 	requireAdminOnly(t, req)
-	resp, err = sendReq(t, req, adminUmputunToken)
+	resp, err = sendReq(req, adminUmputunToken)
 	assert.NoError(t, err)
 	assert.NoError(t, resp.Body.Close())
 	assert.Equal(t, http.StatusOK, resp.StatusCode)
@@ -75,14 +75,22 @@ func TestAdmin_Delete(t *testing.T) {
 	assert.Equal(t, "", cr.Text)
 	assert.True(t, cr.Deleted)

-	time.Sleep(250 * time.Millisecond)
-	// check last comments updated
-	res, code = get(t, ts.URL+"/api/v1/last/2?site=remark42")
-	assert.Equal(t, http.StatusOK, code)
-	comments = []store.Comment{}
-	err = json.Unmarshal([]byte(res), &comments)
-	assert.NoError(t, err)
-	assert.Equal(t, 1, len(comments), "should have 1 comments")
+	// the last-comments list refreshes asynchronously after the delete. the polling closure runs
+	// off the test goroutine, so it asserts on the CollectT it is handed rather than on t, which
+	// also puts the real transport or decode error in the failure message
+	pollClient := http.Client{Timeout: waitTimeout}
+	defer pollClient.CloseIdleConnections()
+	require.EventuallyWithT(t, func(c *assert.CollectT) {
+		lastResp, gErr := pollClient.Get(ts.URL + "/api/v1/last/2?site=remark42")
+		if !assert.NoError(c, gErr) {
+			return
+		}
+		defer lastResp.Body.Close()
+		assert.Equal(c, http.StatusOK, lastResp.StatusCode)
+		last := []store.Comment{}
+		assert.NoError(c, json.NewDecoder(lastResp.Body).Decode(&last))
+		assert.Len(c, last, 1, "should have 1 comments")
+	}, waitTimeout, httpPoll)

 	// check count updated
 	res, code = get(t, ts.URL+"/api/v1/count?site=remark42&url=https://radio-t.com/blah")
@@ -139,7 +147,7 @@ func TestAdmin_Title(t *testing.T) {
 		fmt.Sprintf("%s/api/v1/admin/title/%s?site=remark42&url=%s/post1", ts.URL, id1, tss.URL), http.NoBody)
 	assert.NoError(t, err)
 	requireAdminOnly(t, req)
-	resp, err := sendReq(t, req, adminUmputunToken)
+	resp, err := sendReq(req, adminUmputunToken)
 	require.NoError(t, err)
 	require.NoError(t, resp.Body.Close())
 	assert.Equal(t, http.StatusOK, resp.StatusCode)
@@ -174,7 +182,7 @@ func TestAdmin_DeleteUser(t *testing.T) {
 	req, err := http.NewRequest(http.MethodDelete, fmt.Sprintf("%s/api/v1/admin/user/%s?site=remark42", ts.URL, "id2"), http.NoBody)
 	assert.NoError(t, err)
 	requireAdminOnly(t, req)
-	resp, err := sendReq(t, req, adminUmputunToken)
+	resp, err := sendReq(req, adminUmputunToken)
 	assert.NoError(t, err)
 	require.NoError(t, resp.Body.Close())
 	assert.Equal(t, http.StatusOK, resp.StatusCode)
@@ -275,7 +283,7 @@ func TestAdmin_Block(t *testing.T) {
 		req, err := http.NewRequest(http.MethodPut, url, http.NoBody)
 		assert.NoError(t, err)
 		requireAdminOnly(t, req)
-		resp, err := sendReq(t, req, adminUmputunToken)
+		resp, err := sendReq(req, adminUmputunToken)
 		require.NoError(t, err)
 		body, err = io.ReadAll(resp.Body)
 		assert.NoError(t, err)
@@ -333,10 +341,12 @@ func TestAdmin_Block(t *testing.T) {
 	assert.NoError(t, err)
 	assert.Equal(t, false, j["block"])

-	// block with ttl
+	// block with ttl, checked in place rather than through another admin request, which would
+	// push this test over the 10 req/s limit on that route
 	makeTwoComments()
-	code, _ = block(1, "50ms")
+	code, _ = block(1, "500ms")
 	require.Equal(t, http.StatusOK, code)
+	require.True(t, srv.adminRest.dataService.IsBlocked("remark42", "user1"), "user1 blocked with ttl")

 	// get as regular user
 	res, code = get(t, ts.URL+"/api/v1/find?site=remark42&url=https://radio-t.com/blah&sort=+time")
@@ -350,7 +360,13 @@ func TestAdmin_Block(t *testing.T) {

 	srv.pubRest.cache = cache.NewScache[[]byte](cache.NewNopCache[[]byte]()) // TODO: with lru cache it won't be refreshed and invalidated for long
 	// time
-	time.Sleep(50 * time.Millisecond)
+
+	// the ttl above is wide enough that the checks in between cannot outlast it, so reaching
+	// here still inside the block, and the wait below observes it lapse
+	require.Eventually(t, func() bool {
+		return !srv.adminRest.dataService.IsBlocked("remark42", "user1")
+	}, waitTimeout, pollInterval, "block with ttl did not expire")
+
 	res, code = get(t, ts.URL+"/api/v1/find?site=remark42&url=https://radio-t.com/blah&sort=+time")
 	assert.Equal(t, http.StatusOK, code)
 	comments = commentsWithInfo{}
@@ -383,23 +399,23 @@ func TestAdmin_BlockedList(t *testing.T) {
 	req, err := http.NewRequest(http.MethodPut,
 		fmt.Sprintf("%s/api/v1/admin/user/%s?site=remark42&block=%d", ts.URL, "user1", 1), http.NoBody)
 	assert.NoError(t, err)
-	res, err := sendReq(t, req, adminUmputunToken)
+	res, err := sendReq(req, adminUmputunToken)
 	require.NoError(t, err)
 	require.NoError(t, res.Body.Close())
 	assert.Equal(t, http.StatusOK, res.StatusCode)

-	// block user2
+	// block user2 for long enough that the "two users blocked" check below cannot race the ttl
 	req, err = http.NewRequest(http.MethodPut,
-		fmt.Sprintf("%s/api/v1/admin/user/%s?site=remark42&block=%d&ttl=150ms", ts.URL, "user2", 1), http.NoBody)
+		fmt.Sprintf("%s/api/v1/admin/user/%s?site=remark42&block=%d&ttl=1h", ts.URL, "user2", 1), http.NoBody)
 	assert.NoError(t, err)
-	res, err = sendReq(t, req, adminUmputunToken)
+	res, err = sendReq(req, adminUmputunToken)
 	require.NoError(t, err)
 	require.NoError(t, res.Body.Close())
 	assert.Equal(t, http.StatusOK, res.StatusCode)

 	req, err = http.NewRequest("GET", ts.URL+"/api/v1/admin/blocked?site=remark42", http.NoBody)
 	require.NoError(t, err)
-	res, err = sendReq(t, req, adminUmputunToken)
+	res, err = sendReq(req, adminUmputunToken)
 	require.NoError(t, err)
 	require.Equal(t, http.StatusOK, res.StatusCode)
 	users := []store.BlockedUser{}
@@ -412,18 +428,33 @@ func TestAdmin_BlockedList(t *testing.T) {
 	assert.Equal(t, "user2", users[1].ID)
 	assert.Equal(t, "user2 name", users[1].Name)
 	t.Logf("%+v", users)
-	time.Sleep(150 * time.Millisecond)

-	req, err = http.NewRequest("GET", ts.URL+"/api/v1/admin/blocked?site=remark42", http.NoBody)
+	// re-block user2 with a short ttl and wait for it to lapse, so the lapse is observed
+	// independently of the check above
+	req, err = http.NewRequest(http.MethodPut,
+		fmt.Sprintf("%s/api/v1/admin/user/%s?site=remark42&block=%d&ttl=150ms", ts.URL, "user2", 1), http.NoBody)
 	require.NoError(t, err)
-	res, err = sendReq(t, req, adminUmputunToken)
+	res, err = sendReq(req, adminUmputunToken)
 	require.NoError(t, err)
-	require.Equal(t, http.StatusOK, res.StatusCode)
-	users = []store.BlockedUser{}
-	err = json.NewDecoder(res.Body).Decode(&users)
-	assert.NoError(t, err)
 	require.NoError(t, res.Body.Close())
-	assert.Equal(t, 1, len(users), "one user left blocked")
+	require.Equal(t, http.StatusOK, res.StatusCode)
+
+	// the closure runs off the test goroutine and asserts on the CollectT it is handed, never on t
+	require.EventuallyWithT(t, func(c *assert.CollectT) {
+		blockedReq, reqErr := http.NewRequest("GET", ts.URL+"/api/v1/admin/blocked?site=remark42", http.NoBody)
+		if !assert.NoError(c, reqErr) {
+			return
+		}
+		blockedResp, sendErr := sendReq(blockedReq, adminUmputunToken)
+		if !assert.NoError(c, sendErr) {
+			return
+		}
+		defer blockedResp.Body.Close()
+		assert.Equal(c, http.StatusOK, blockedResp.StatusCode)
+		blocked := []store.BlockedUser{}
+		assert.NoError(c, json.NewDecoder(blockedResp.Body).Decode(&blocked))
+		assert.Len(c, blocked, 1, "one user left blocked")
+	}, waitTimeout, httpPoll)
 }

 func TestAdmin_ReadOnly(t *testing.T) {
@@ -448,11 +479,11 @@ func TestAdmin_ReadOnly(t *testing.T) {
 	req, err := http.NewRequest(http.MethodPut,
 		fmt.Sprintf("%s/api/v1/admin/readonly?site=remark42&url=https://radio-t.com/blah&ro=1", ts.URL), http.NoBody)
 	assert.NoError(t, err)
-	resp, err := sendReq(t, req, "") // non-admin user
+	resp, err := sendReq(req, "") // non-admin user
 	require.NoError(t, err)
 	require.NoError(t, resp.Body.Close())
 	assert.Equal(t, http.StatusUnauthorized, resp.StatusCode)
-	resp, err = sendReq(t, req, adminUmputunToken)
+	resp, err = sendReq(req, adminUmputunToken)
 	require.NoError(t, err)
 	require.NoError(t, resp.Body.Close())
 	assert.Equal(t, http.StatusOK, resp.StatusCode)
@@ -467,7 +498,7 @@ func TestAdmin_ReadOnly(t *testing.T) {
 	assert.NoError(t, err, "can't marshal comment %+v", c)
 	req, err = http.NewRequest("POST", ts.URL+"/api/v1/comment?site=remark42", bytes.NewBuffer(b))
 	require.NoError(t, err)
-	resp, err = sendReq(t, req, adminUmputunToken)
+	resp, err = sendReq(req, adminUmputunToken)
 	require.NoError(t, err)
 	require.NoError(t, resp.Body.Close())
 	assert.Equal(t, http.StatusForbidden, resp.StatusCode)
@@ -476,7 +507,7 @@ func TestAdmin_ReadOnly(t *testing.T) {
 	req, err = http.NewRequest(http.MethodPut,
 		fmt.Sprintf("%s/api/v1/admin/readonly?site=remark42&url=https://radio-t.com/blah&ro=0", ts.URL), http.NoBody)
 	assert.NoError(t, err)
-	resp, err = sendReq(t, req, adminUmputunToken)
+	resp, err = sendReq(req, adminUmputunToken)
 	require.NoError(t, err)
 	require.NoError(t, resp.Body.Close())
 	assert.Equal(t, http.StatusOK, resp.StatusCode)
@@ -491,7 +522,7 @@ func TestAdmin_ReadOnly(t *testing.T) {
 	assert.NoError(t, err, "can't marshal comment %+v", c)
 	req, err = http.NewRequest("POST", ts.URL+"/api/v1/comment?site="+c.Locator.SiteID, bytes.NewBuffer(b))
 	require.NoError(t, err)
-	resp, err = sendReq(t, req, adminUmputunToken)
+	resp, err = sendReq(req, adminUmputunToken)
 	require.NoError(t, err)
 	require.NoError(t, resp.Body.Close())
 	assert.Equal(t, http.StatusCreated, resp.StatusCode)
@@ -506,7 +537,7 @@ func TestAdmin_ReadOnlyNoComments(t *testing.T) {
 		fmt.Sprintf("%s/api/v1/admin/readonly?site=remark42&url=https://radio-t.com/blah&ro=1", ts.URL), http.NoBody)
 	assert.NoError(t, err)
 	requireAdminOnly(t, req)
-	resp, err := sendReq(t, req, adminUmputunToken)
+	resp, err := sendReq(req, adminUmputunToken)
 	require.NoError(t, err)
 	require.NoError(t, resp.Body.Close())
 	assert.Equal(t, http.StatusOK, resp.StatusCode)
@@ -553,7 +584,7 @@ func TestAdmin_ReadOnlyWithAge(t *testing.T) {
 		fmt.Sprintf("%s/api/v1/admin/readonly?site=remark42&url=https://radio-t.com/blah&ro=1", ts.URL), http.NoBody)
 	assert.NoError(t, err)
 	requireAdminOnly(t, req)
-	resp, err := sendReq(t, req, adminUmputunToken)
+	resp, err := sendReq(req, adminUmputunToken)
 	require.NoError(t, err)
 	require.NoError(t, resp.Body.Close())
 	assert.Equal(t, http.StatusOK, resp.StatusCode)
@@ -565,7 +596,7 @@ func TestAdmin_ReadOnlyWithAge(t *testing.T) {
 	req, err = http.NewRequest(http.MethodPut,
 		fmt.Sprintf("%s/api/v1/admin/readonly?site=remark42&url=https://radio-t.com/blah&ro=0", ts.URL), http.NoBody)
 	assert.NoError(t, err)
-	resp, err = sendReq(t, req, adminUmputunToken)
+	resp, err = sendReq(req, adminUmputunToken)
 	require.NoError(t, err)
 	require.NoError(t, resp.Body.Close())
 	assert.Equal(t, http.StatusForbidden, resp.StatusCode)
@@ -594,7 +625,7 @@ func TestAdmin_Verify(t *testing.T) {
 		fmt.Sprintf("%s/api/v1/admin/verify/user1?site=remark42&verified=1", ts.URL), http.NoBody)
 	assert.NoError(t, err)
 	requireAdminOnly(t, req)
-	resp, err := sendReq(t, req, adminUmputunToken)
+	resp, err := sendReq(req, adminUmputunToken)
 	require.NoError(t, err)
 	require.NoError(t, resp.Body.Close())
 	assert.Equal(t, http.StatusOK, resp.StatusCode)
@@ -613,7 +644,7 @@ func TestAdmin_Verify(t *testing.T) {
 	req, err = http.NewRequest(http.MethodPut,
 		fmt.Sprintf("%s/api/v1/admin/verify/user1?site=remark42&verified=0", ts.URL), http.NoBody)
 	assert.NoError(t, err)
-	resp, err = sendReq(t, req, adminUmputunToken)
+	resp, err = sendReq(req, adminUmputunToken)
 	require.NoError(t, err)
 	require.NoError(t, resp.Body.Close())
 	assert.Equal(t, http.StatusOK, resp.StatusCode)
@@ -664,7 +695,7 @@ func TestAdmin_ExportFile(t *testing.T) {
 	req, err := http.NewRequest("GET", ts.URL+"/api/v1/admin/export?site=remark42&mode=file", http.NoBody)
 	require.NoError(t, err)
 	requireAdminOnly(t, req)
-	resp, err := sendReq(t, req, adminUmputunToken)
+	resp, err := sendReq(req, adminUmputunToken)
 	require.NoError(t, err)

 	assert.Equal(t, http.StatusOK, resp.StatusCode)
@@ -50,6 +50,39 @@ func TestRouteTimeout(t *testing.T) {
 	assert.Equal(t, http.StatusOK, resp.StatusCode, "route without R.Timeout runs to completion")
 }

+// TestRateLimiter covers the middleware guarding every route group: a burst past the per-second
+// allowance is refused with 429, and a client under the allowance is not. The limiter keys on
+// RemoteAddr, so the two cases use different ones rather than waiting for a bucket to refill.
+func TestRateLimiter(t *testing.T) {
+	router := routegroup.New(http.NewServeMux())
+	router.With(rateLimiter(1)).HandleFunc("GET /limited", func(http.ResponseWriter, *http.Request) {})
+	ts := httptest.NewServer(router)
+	defer ts.Close()
+
+	call := func(remoteAddr string) int {
+		req := httptest.NewRequest("GET", "http://example.com/limited", http.NoBody)
+		req.RemoteAddr = remoteAddr
+		w := httptest.NewRecorder()
+		router.ServeHTTP(w, req)
+		resp := w.Result()
+		assert.NoError(t, resp.Body.Close())
+		return resp.StatusCode
+	}
+
+	// one request a second is allowed, so the first of a burst passes and the rest are refused
+	assert.Equal(t, http.StatusOK, call("1.2.3.4:1000"), "first request within the allowance")
+	refused := 0
+	for range 5 {
+		if call("1.2.3.4:1000") == http.StatusTooManyRequests {
+			refused++
+		}
+	}
+	assert.Equal(t, 5, refused, "burst past the allowance is refused")
+
+	// a different client has its own bucket and is unaffected
+	assert.Equal(t, http.StatusOK, call("5.6.7.8:1000"), "limit is per client, not global")
+}
+
 func TestRealIPMiddleware(t *testing.T) {
 	// call runs mw with the given peer and (optional) X-Real-IP header and returns what the
 	// downstream handler observes; state is per-call, so subtests don't share closure locals.
@@ -34,7 +34,7 @@ func TestMigrator_Import(t *testing.T) {
 "ip":"ae12fe3b5f129b5cc4cdd2b136b7b7947c4d2741"},"locator":{"site":"remark42","url":"https://radio-t.com/blah2"},"score":0,
 "votes":{},"time":"2018-04-30T01:37:00.861387771-05:00"}`)

-	client := &http.Client{Timeout: 1 * time.Second}
+	client := &http.Client{Timeout: waitTimeout}
 	defer client.CloseIdleConnections()
 	req, err := http.NewRequest("POST", ts.URL+"/api/v1/admin/import?site=remark42&provider=native", r)
 	require.NoError(t, err)
@@ -125,7 +125,7 @@ func TestMigrator_ImportFromWP(t *testing.T) {

 	r := strings.NewReader(strings.ReplaceAll(xmlTestWP, "'", "`"))

-	client := &http.Client{Timeout: 1 * time.Second}
+	client := &http.Client{Timeout: waitTimeout}
 	defer client.CloseIdleConnections()
 	req, err := http.NewRequest("POST", ts.URL+"/api/v1/admin/import?site=remark42&provider=wordpress", r)
 	assert.NoError(t, err)
@@ -170,7 +170,7 @@ func TestMigrator_ImportFromCommento(t *testing.T) {
 "email":"somegreatmail@gmail.com","name":"User5276","link":"https://example.com/profile/257","photo":"https://secure.gravatar.com/avatar/8f279626d26175134b0d5c88648172f7",
 "provider":"sso:example.com","joinDate":"2021-03-19T19:27:25.954285Z","isModerator":false}]}`)

-	client := &http.Client{Timeout: 1 * time.Second}
+	client := &http.Client{Timeout: waitTimeout}
 	defer client.CloseIdleConnections()
 	req, err := http.NewRequest("POST", ts.URL+"/api/v1/admin/import?site=remark42&provider=commento", r)
 	assert.NoError(t, err)
@@ -211,7 +211,7 @@ func TestMigrator_ImportFromCommentoJSON(t *testing.T) {
 	r, err := os.Open("testdata/commento.json")
 	require.NoError(t, err)

-	client := &http.Client{Timeout: 1 * time.Second}
+	client := &http.Client{Timeout: waitTimeout}
 	defer client.CloseIdleConnections()
 	req, err := http.NewRequest("POST", ts.URL+"/api/v1/admin/import?site=remark42&provider=commento", r)
 	assert.NoError(t, err)
@@ -258,7 +258,7 @@ func TestMigrator_ImportRejected(t *testing.T) {
 "ip":"ae12fe3b5f129b5cc4cdd2b136b7b7947c4d2741"},"locator":{"site":"remark42","url":"https://radio-t.com/blah2"},"score":0,
 "votes":{},"time":"2018-04-30T01:37:00.861387771-05:00"}`)

-	client := &http.Client{Timeout: 1 * time.Second}
+	client := &http.Client{Timeout: waitTimeout}
 	defer client.CloseIdleConnections()
 	req, err := http.NewRequest("POST", ts.URL+"/api/v1/admin/import?site=remark42&provider=native&secret=XYZ", r)
 	assert.NoError(t, err)
@@ -281,7 +281,7 @@ func TestMigrator_ImportDouble(t *testing.T) {
 		recs = append(recs, fmt.Sprintf(tmpl, i))
 	}
 	r := strings.NewReader(`{"version":1}` + strings.Join(recs, "\n")) // reader with 10k records
-	client := &http.Client{Timeout: 1 * time.Second}
+	client := &http.Client{Timeout: waitTimeout}
 	defer client.CloseIdleConnections()
 	req, err := http.NewRequest("POST", ts.URL+"/api/v1/admin/import?site=remark42&provider=native", r)
 	require.NoError(t, err)
@@ -380,7 +380,7 @@ func TestMigrator_Export(t *testing.T) {
 "votes":{},"time":"2018-04-30T01:37:00.861387771-05:00"}`)

 	// import comments first
-	client := &http.Client{Timeout: 1 * time.Second}
+	client := &http.Client{Timeout: waitTimeout}
 	defer client.CloseIdleConnections()
 	req, err := http.NewRequest("POST", ts.URL+"/api/v1/admin/import?site=remark42&provider=native", r)
 	require.NoError(t, err)
@@ -573,7 +573,7 @@ func TestMigrator_RemapReject(t *testing.T) {
 	defer teardown()

 	// without admin credentials
-	client := &http.Client{Timeout: 1 * time.Second}
+	client := &http.Client{Timeout: waitTimeout}
 	defer client.CloseIdleConnections()
 	rules := strings.NewReader(`https://remark42.com/* https://www.remark42.com/*`)
 	req, err := http.NewRequest("POST", ts.URL+"/api/v1/admin/remap?site=remark42", rules)
@@ -144,7 +144,7 @@ func TestRest_CreateAndPreviewWithImage(t *testing.T) {

 		assert.Equal(t, false, pngRead, "original image is not yet accessed by server")
 		// retrieve the image from the cache
-		imgURL := strings.Split(strings.Split(string(b), "src=\"")[1], "\"")[0]
+		imgURL, _, _ := strings.Cut(strings.Split(string(b), "src=\"")[1], "\"")
 		// replace srv.RemarkURL with ts.URL
 		imgURL = strings.ReplaceAll(imgURL, srv.RemarkURL, ts.URL)
 		resp, err = http.Get(imgURL)
@@ -432,6 +432,7 @@ func TestRest_Update(t *testing.T) {
 		strings.NewReader(`{"text":"updated text", "summary":"my edit"}`))
 	assert.NoError(t, err)
 	req.Header.Add("X-JWT", devToken)
+	beforeUpdate := time.Now()
 	b, err := client.Do(req)
 	assert.NoError(t, err)
 	body, err := io.ReadAll(b.Body)
@@ -447,7 +448,7 @@ func TestRest_Update(t *testing.T) {
 	assert.Equal(t, "<p>updated text</p>\n", c2.Text)
 	assert.Equal(t, "updated text", c2.Orig)
 	assert.Equal(t, "my edit", c2.Edit.Summary)
-	assert.True(t, time.Since(c2.Edit.Timestamp) < 1*time.Second)
+	assert.WithinRange(t, c2.Edit.Timestamp, beforeUpdate, time.Now(), "edit stamped during the update")

 	// read updated comment
 	res, code := getWithAdminAuth(t, fmt.Sprintf("%s/api/v1/id/%s?site=remark42&url=https://radio-t.com/blah1", ts.URL, id))
@@ -596,7 +597,7 @@ func TestRest_DeleteChildThenParent(t *testing.T) {
 		fmt.Sprintf("%s/api/v1/admin/comment/%s?site=remark42&url=https://radio-t.com/blah1", ts.URL, idC2), http.NoBody)
 	require.NoError(t, err)
 	requireAdminOnly(t, req)
-	resp, err = sendReq(t, req, adminUmputunToken)
+	resp, err = sendReq(req, adminUmputunToken)
 	assert.NoError(t, err)
 	assert.NoError(t, resp.Body.Close())
 	assert.Equal(t, http.StatusOK, resp.StatusCode)
@@ -784,7 +785,7 @@ func TestRest_Vote(t *testing.T) {
 	req, err := http.NewRequest("GET",
 		fmt.Sprintf("%s/api/v1/id/%s?site=remark42&url=https://radio-t.com/blah", ts.URL, id1), http.NoBody)
 	assert.NoError(t, err)
-	resp, err := sendReq(t, req, adminUmputunToken)
+	resp, err := sendReq(req, adminUmputunToken)
 	assert.NoError(t, err)
 	assert.Equal(t, http.StatusOK, resp.StatusCode)
 	cr = store.Comment{}
@@ -974,9 +975,7 @@ func TestRest_EmailNotification(t *testing.T) {
 	require.Equal(t, http.StatusCreated, resp.StatusCode, string(body))
 	parentComment := store.Comment{}
 	require.NoError(t, json.Unmarshal(body, &parentComment))
-	// wait for mock notification Submit to kick off
-	time.Sleep(time.Millisecond * 30)
-	require.Equal(t, 1, len(mockDestination.Get()))
+	waitForCount(t, 1, func() int { return len(mockDestination.Get()) })
 	assert.Empty(t, mockDestination.Get()[0].Emails)

 	// create child comment from another user, email notification only to admin expected
@@ -994,9 +993,7 @@ func TestRest_EmailNotification(t *testing.T) {
 	require.NoError(t, err)
 	require.NoError(t, resp.Body.Close())
 	require.Equal(t, http.StatusCreated, resp.StatusCode, string(body))
-	// wait for mock notification Submit to kick off
-	time.Sleep(time.Millisecond * 30)
-	require.Equal(t, 2, len(mockDestination.Get()))
+	waitForCount(t, 2, func() int { return len(mockDestination.Get()) })
 	assert.Empty(t, mockDestination.Get()[1].Emails)

 	// send confirmation token for email
@@ -1013,9 +1010,7 @@ func TestRest_EmailNotification(t *testing.T) {
 	require.NoError(t, err)
 	require.NoError(t, resp.Body.Close())
 	require.Equal(t, http.StatusOK, resp.StatusCode, string(body))
-	// wait for mock notification Submit to kick off
-	time.Sleep(time.Millisecond * 30)
-	require.Equal(t, 1, len(mockDestination.GetVerify()))
+	waitForCount(t, 1, func() int { return len(mockDestination.GetVerify()) })
 	assert.Equal(t, "good@example.com", mockDestination.GetVerify()[0].Email)
 	verificationToken := mockDestination.GetVerify()[0].Token

@@ -1087,9 +1082,7 @@ func TestRest_EmailNotification(t *testing.T) {
 	require.NoError(t, err)
 	require.NoError(t, resp.Body.Close())
 	require.Equal(t, http.StatusCreated, resp.StatusCode, string(body))
-	// wait for mock notification Submit to kick off
-	time.Sleep(time.Millisecond * 30)
-	require.Equal(t, 3, len(mockDestination.Get()))
+	waitForCount(t, 3, func() int { return len(mockDestination.Get()) })
 	assert.Equal(t, []string{"good@example.com"}, mockDestination.Get()[2].Emails)

 	// delete user's email
@@ -1117,9 +1110,7 @@ func TestRest_EmailNotification(t *testing.T) {
 	require.NoError(t, err)
 	require.NoError(t, resp.Body.Close())
 	require.Equal(t, http.StatusCreated, resp.StatusCode, string(body))
-	// wait for mock notification Submit to kick off
-	time.Sleep(time.Millisecond * 30)
-	require.Equal(t, 4, len(mockDestination.Get()))
+	waitForCountSettled(t, 4, func() int { return len(mockDestination.Get()) })
 	assert.Empty(t, mockDestination.Get()[3].Emails)

 	// confirm email via subscribe call with query params, old behavior, email notification is expected
@@ -1136,9 +1127,7 @@ func TestRest_EmailNotification(t *testing.T) {
 	require.NoError(t, err)
 	require.NoError(t, resp.Body.Close())
 	require.Equal(t, http.StatusOK, resp.StatusCode, string(body))
-	// wait for mock notification Submit to kick off
-	time.Sleep(time.Millisecond * 30)
-	require.Equal(t, 2, len(mockDestination.GetVerify()), "verification email was sent")
+	waitForCount(t, 2, func() int { return len(mockDestination.GetVerify()) }, "verification email was sent")

 	// get email user information to verify there is no subscription yet
 	req, err = http.NewRequest(
@@ -1173,9 +1162,7 @@ func TestRest_EmailNotification(t *testing.T) {
 	require.NoError(t, err)
 	require.NoError(t, resp.Body.Close())
 	require.Equal(t, http.StatusOK, resp.StatusCode, string(body))
-	// wait for mock notification Submit to kick off
-	time.Sleep(time.Millisecond * 30)
-	require.Equal(t, 2, len(mockDestination.GetVerify()), "no new verification email was sent")
+	waitForCountSettled(t, 2, func() int { return len(mockDestination.GetVerify()) }, "no new verification email was sent")

 	// get email user information to verify the subscription happened without the confirmation call
 	req, err = http.NewRequest(
@@ -1224,9 +1211,7 @@ func TestRest_TelegramNotification(t *testing.T) {
 	require.Equal(t, http.StatusCreated, resp.StatusCode, string(body))
 	parentComment := store.Comment{}
 	require.NoError(t, json.Unmarshal(body, &parentComment))
-	// wait for mock notification Submit to kick off
-	time.Sleep(time.Millisecond * 30)
-	require.Equal(t, 1, len(mockDestination.Get()))
+	waitForCount(t, 1, func() int { return len(mockDestination.Get()) })
 	assert.Empty(t, mockDestination.Get()[0].Telegrams)

 	// create child comment from another user, telegram notification only to admin expected
@@ -1244,9 +1229,7 @@ func TestRest_TelegramNotification(t *testing.T) {
 	require.NoError(t, err)
 	require.NoError(t, resp.Body.Close())
 	require.Equal(t, http.StatusCreated, resp.StatusCode, string(body))
-	// wait for mock notification Submit to kick off
-	time.Sleep(time.Millisecond * 30)
-	require.Equal(t, 2, len(mockDestination.Get()))
+	waitForCount(t, 2, func() int { return len(mockDestination.Get()) })
 	assert.Empty(t, mockDestination.Get()[1].Telegrams)

 	// subscribe to telegram while the telegram destination is absent
@@ -1357,9 +1340,7 @@ func TestRest_TelegramNotification(t *testing.T) {
 	require.NoError(t, err)
 	require.NoError(t, resp.Body.Close())
 	require.Equal(t, http.StatusCreated, resp.StatusCode, string(body))
-	// wait for mock notification Submit to kick off
-	time.Sleep(time.Millisecond * 30)
-	require.Equal(t, 3, len(mockDestination.Get()))
+	waitForCount(t, 3, func() int { return len(mockDestination.Get()) })
 	assert.Equal(t, []string{"good_telegram"}, mockDestination.Get()[2].Telegrams)

 	// delete user's telegram
@@ -1387,9 +1368,7 @@ func TestRest_TelegramNotification(t *testing.T) {
 	require.NoError(t, err)
 	require.NoError(t, resp.Body.Close())
 	require.Equal(t, http.StatusCreated, resp.StatusCode, string(body))
-	// wait for mock notification Submit to kick off
-	time.Sleep(time.Millisecond * 30)
-	require.Equal(t, 4, len(mockDestination.Get()))
+	waitForCountSettled(t, 4, func() int { return len(mockDestination.Get()) })
 	assert.Empty(t, mockDestination.Get()[3].Telegrams)
 }

@@ -1412,7 +1391,7 @@ func TestRest_UserAllData(t *testing.T) {
 	_, err = srv.DataService.Create(c3)
 	require.NoError(t, err)

-	client := &http.Client{Timeout: 1 * time.Second}
+	client := &http.Client{Timeout: waitTimeout}
 	defer client.CloseIdleConnections()
 	req, err := http.NewRequest("GET", ts.URL+"/api/v1/userdata?site=remark42", http.NoBody)
 	require.NoError(t, err)
@@ -1465,7 +1444,7 @@ func TestRest_UserAllDataManyComments(t *testing.T) {
 		_, err := srv.DataService.Create(c)
 		require.NoError(t, err)
 	}
-	client := &http.Client{Timeout: 1 * time.Second}
+	client := &http.Client{Timeout: waitTimeout}
 	defer client.CloseIdleConnections()
 	req, err := http.NewRequest("GET", ts.URL+"/api/v1/userdata?site=remark42", http.NoBody)
 	require.NoError(t, err)
@@ -1608,7 +1587,9 @@ func TestRest_CreateWithPictures(t *testing.T) {
 		Staging:  "/tmp/remark42/images.staging",
 		Location: "/tmp/remark42/images",
 	}, image.ServiceParams{
-		EditDuration: 100 * time.Millisecond,
+		// the "not moved yet" checks below run right after the comment POST returns, so the
+		// commit window has to be wide enough that a stalled runner cannot close it first
+		EditDuration: 3 * time.Second,
 		MaxSize:      2000,
 		ImageAPI:     svc.RemarkURL + "/api/v1/picture/",
 		ProxyAPI:     svc.RemarkURL + "/api/v1/img",
@@ -1671,11 +1652,12 @@ func TestRest_CreateWithPictures(t *testing.T) {
 		assert.Error(t, err, "picture %d not moved from staging yet", i)
 	}

-	time.Sleep(1500 * time.Millisecond)
-
+	// the commit runs once EditDuration expires
 	for i := range ids {
-		_, err = os.Stat("/tmp/remark42/images/" + ids[i])
-		assert.NoError(t, err, "picture %d moved from staging and available in permanent location", i)
+		require.Eventually(t, func() bool {
+			_, e := os.Stat("/tmp/remark42/images/" + ids[i])
+			return e == nil
+		}, waitTimeout, pollInterval, "picture %d moved from staging and available in permanent location", i)
 	}
 }

@@ -381,11 +381,12 @@ func TestRest_Last(t *testing.T) {
 	c2 := store.Comment{Text: "test test #2", ParentID: "p1",
 		Locator: store.Locator{SiteID: "remark42", URL: "https://radio-t.com/blah2"}}

-	// add 3 comments
+	// add 3 comments, with the clock pushed past a millisecond boundary in between so the two
+	// "since" values below are distinct
 	ts1 := time.Now().UnixNano() / 1000000
 	addComment(t, c1, ts)
 	id1 := addComment(t, c1, ts)
-	time.Sleep(10 * time.Millisecond)
+	waitPastMillisecond(time.Now())
 	ts2 := time.Now().UnixNano() / 1000000
 	id2 := addComment(t, c2, ts)

@@ -539,9 +540,17 @@ func TestRest_FindUserComments_CWE_918(t *testing.T) {
 	assert.Equal(t, arbitraryServer.URL, resp.Comments[0].Locator.URL, "arbitrary URL provided by the request")
 }

+// waitPastMillisecond blocks until the wall clock moves past ts's millisecond, so whatever is
+// created next gets a distinct value for the millisecond-precision "since" filter
+func waitPastMillisecond(ts time.Time) {
+	next := ts.Truncate(time.Millisecond).Add(time.Millisecond)
+	time.Sleep(time.Until(next) + time.Microsecond) // a non-positive duration returns at once
+}
+
 func TestPublic_FindCommentsCtrl_ConsistentCount(t *testing.T) {
 	// test that comment counting is consistent between tree and plain formats
-	ts, srv, teardown := startupT(t)
+	// the open-route limit is lifted so the subtests below can run back to back
+	ts, srv, teardown := startupT(t, func(srv *Rest) { srv.openRouteLimiter = 100000 })
 	defer teardown()

 	commentLocator := store.Locator{URL: "test-url", SiteID: "remark42"}
@@ -567,55 +576,55 @@ func TestPublic_FindCommentsCtrl_ConsistentCount(t *testing.T) {
 	}

 	// adding initial comments (8 to test-url and 1 to another-url) and voting, and delete two of comments to the first post.
-	// with sleep so that at least few millisecond pass between each comment
-	// and later we would be able to use that in "since" filter with millisecond precision
+	// each comment waits for the clock to pass the previous one's millisecond so the "since"
+	// filter, which has millisecond precision, can tell them apart
 	ids := make([]string, 9)
 	timestamps := make([]time.Time, 9)
 	c1 := store.Comment{Text: "top-level comment 1", Locator: commentLocator}
 	ids[0], timestamps[0] = addCommentGetCreatedTime(t, c1, ts)
 	// #3 by score
 	setScore(commentLocator, ids[0], 1)
-	time.Sleep(time.Millisecond * 5)
+	waitPastMillisecond(timestamps[0])

 	c2 := store.Comment{Text: "top-level comment 2", Locator: commentLocator}
 	ids[1], timestamps[1] = addCommentGetCreatedTime(t, c2, ts)
 	// #2 by score
 	setScore(commentLocator, ids[1], 2)
-	time.Sleep(time.Millisecond * 5)
+	waitPastMillisecond(timestamps[1])

 	c3 := store.Comment{Text: "second-level comment 1", ParentID: ids[0], Locator: commentLocator}
 	ids[2], timestamps[2] = addCommentGetCreatedTime(t, c3, ts)
 	// #1 by score
 	setScore(commentLocator, ids[2], 10)
-	time.Sleep(time.Millisecond * 5)
+	waitPastMillisecond(timestamps[2])

 	c4 := store.Comment{Text: "third-level comment 1", ParentID: ids[2], Locator: commentLocator}
 	ids[3], timestamps[3] = addCommentGetCreatedTime(t, c4, ts)
 	// #5 by score, #1 by controversy
 	setScore(commentLocator, ids[3], 4)
 	setScore(commentLocator, ids[3], -4)
-	time.Sleep(time.Millisecond * 5)
+	waitPastMillisecond(timestamps[3])

 	c5 := store.Comment{Text: "second-level comment 2", ParentID: ids[1], Locator: commentLocator}
 	ids[4], timestamps[4] = addCommentGetCreatedTime(t, c5, ts)
 	// #5 by score, #2 by controversy
 	setScore(commentLocator, ids[4], 2)
 	setScore(commentLocator, ids[4], -3)
-	time.Sleep(time.Millisecond * 5)
+	waitPastMillisecond(timestamps[4])

 	c6 := store.Comment{Text: "deleted third-level comment 2", ParentID: ids[4], Locator: commentLocator}
 	ids[5], timestamps[5] = addCommentGetCreatedTime(t, c6, ts)
 	// deleted later so not visible in site-wide requests
 	setScore(commentLocator, ids[5], 10)
 	setScore(commentLocator, ids[5], -10)
-	time.Sleep(time.Millisecond * 5)
+	waitPastMillisecond(timestamps[5])

 	c7 := store.Comment{Text: "top-level comment 3", Locator: commentLocator}
 	ids[6], timestamps[6] = addCommentGetCreatedTime(t, c7, ts)
 	// #6 by score, #4 by controversy
 	setScore(commentLocator, ids[6], -3)
 	setScore(commentLocator, ids[6], 1)
-	time.Sleep(time.Millisecond * 5)
+	waitPastMillisecond(timestamps[6])

 	c8 := store.Comment{Text: "deleted second-level comment 3", ParentID: ids[6], Locator: commentLocator}
 	ids[7], timestamps[7] = addCommentGetCreatedTime(t, c8, ts)
@@ -782,8 +791,6 @@ func TestPublic_FindCommentsCtrl_ConsistentCount(t *testing.T) {
 			assert.Equal(t, expectedStatus, code)
 			assert.Contains(t, body, tc.expectedBody)
 			t.Log(body)
-			// prevent hit limiter from engaging
-			time.Sleep(80 * time.Millisecond)
 		})
 	}
 }
@@ -8,7 +8,6 @@ import (
 	"fmt"
 	"io"
 	"io/fs"
-	"math/rand"
 	"net"
 	"net/http"
 	"net/http/httptest"
@@ -368,20 +367,25 @@ func TestRest_AvatarMounts(t *testing.T) {

 func TestRest_Shutdown(t *testing.T) {
 	srv := Rest{Authenticator: &auth.Service{}, ImageProxy: &proxy.Image{}}
+	port := chooseUnusedPort(t)
 	done := make(chan bool)

 	// without waiting for channel close at the end goroutine will stay alive after test finish
 	// which would create data race with next test
 	go func() {
-		time.Sleep(200 * time.Millisecond)
-		srv.Shutdown()
+		srv.Run("127.0.0.1", port)
 		close(done)
 	}()

-	st := time.Now()
-	srv.Run("127.0.0.1", 0)
-	assert.True(t, time.Since(st).Seconds() < 1, "should take about 100ms")
-	<-done
+	defer srv.Shutdown() // a failed readiness wait must not leave srv.Run behind for goleak
+	waitForServerStart(t, port)
+	srv.Shutdown()
+
+	select {
+	case <-done:
+	case <-time.After(serverStopTimeout):
+		t.Fatal("rest server did not stop after Shutdown")
+	}
 }

 func TestRest_filterComments(t *testing.T) {
@@ -400,7 +404,7 @@ func TestRest_filterComments(t *testing.T) {
 }

 func TestRest_RunStaticSSLMode(t *testing.T) {
-	sslPort := chooseRandomUnusedPort()
+	sslPort := chooseUnusedPort(t)
 	srv := Rest{
 		Authenticator: auth.NewService(auth.Opts{
 			AvatarStore:       avatar.NewLocalFS("/tmp"),
@@ -417,12 +421,12 @@ func TestRest_RunStaticSSLMode(t *testing.T) {
 		RemarkURL: fmt.Sprintf("https://localhost:%d", sslPort),
 	}

-	port := chooseRandomUnusedPort()
+	port := chooseUnusedPort(t)
 	go func() {
 		srv.Run("", port)
 	}()

-	waitForHTTPSServerStart(sslPort)
+	waitForServerStart(t, sslPort, port)

 	client := http.Client{
 		// prevent http redirect
@@ -455,7 +459,7 @@ func TestRest_RunStaticSSLMode(t *testing.T) {
 }

 func TestRest_RunAutocertModeHTTPOnly(t *testing.T) {
-	sslPort := chooseRandomUnusedPort()
+	sslPort := chooseUnusedPort(t)
 	srv := Rest{
 		Authenticator: &auth.Service{},
 		ImageProxy:    &proxy.Image{},
@@ -466,13 +470,13 @@ func TestRest_RunAutocertModeHTTPOnly(t *testing.T) {
 		RemarkURL: fmt.Sprintf("https://localhost:%d", sslPort),
 	}

-	port := chooseRandomUnusedPort()
+	port := chooseUnusedPort(t)
 	go func() {
 		// can't check https server locally, just only http server
 		srv.Run("", port)
 	}()

-	waitForHTTPSServerStart(sslPort)
+	waitForServerStart(t, sslPort, port)

 	client := http.Client{
 		// prevent http redirect
@@ -586,25 +590,11 @@ func TestRest_frameAncestors(t *testing.T) {
 	assert.Contains(t, resp.Header.Get("Content-Security-Policy"), "frame-ancestors *;")
 }

-// randomPath pick a file or folder name which is not in use for sure
-func randomPath(tempDir, basename, suffix string) (string, error) {
-	for range 10 {
-		fname := fmt.Sprintf("/%s/%s-%d%s", tempDir, basename, rand.Int31(), suffix)
-		fmt.Printf("fname %q", fname)
-		_, err := os.Stat(fname)
-		if err != nil {
-			return fname, nil
-		}
-	}
-	return "", fmt.Errorf("cannot create temp file in %s", tempDir)
-}
-
 // startupT runs fully configured testing server
 // srvHook is an optional func to set some Rest param after the creation but prior to Run
 func startupT(t *testing.T, srvHook ...func(srv *Rest)) (ts *httptest.Server, srv *Rest, teardown func()) {
 	tmp := os.TempDir()
-	testDB, err := randomPath(tmp, "test-remark", ".db")
-	require.NoError(t, err)
+	testDB := filepath.Join(t.TempDir(), "test-remark.db") // per-test dir, removed when the test ends

 	_ = os.RemoveAll(tmp + "/ava-remark42")
 	_ = os.RemoveAll(tmp + "/pics-remark42")
@@ -685,7 +675,6 @@ func startupT(t *testing.T, srvHook ...func(srv *Rest)) (ts *httptest.Server, sr
 	teardown = func() {
 		ts.Close()
 		require.NoError(t, srv.DataService.Close())
-		_ = os.Remove(testDB)
 		_ = os.RemoveAll(tmp + "/ava-remark42")
 		_ = os.RemoveAll(tmp + "/pics-remark42")
 	}
@@ -693,6 +682,44 @@ func startupT(t *testing.T, srvHook ...func(srv *Rest)) (ts *httptest.Server, sr
 	return ts, srv, teardown
 }

+const (
+	// outer bound before a wait is called a hang, generous enough for a loaded CI runner
+	waitTimeout  = 30 * time.Second
+	pollInterval = 10 * time.Millisecond
+
+	// budget for a server to stop once asked, tight enough to catch a shutdown that hangs
+	serverStopTimeout = 10 * time.Second
+
+	// connect budget for a single probe, kept off the poll interval so a slow loopback connect
+	// on a loaded runner does not look like a server that is not listening
+	probeDialTimeout = time.Second
+
+	// window to prove something did not happen
+	notifySettle = 300 * time.Millisecond
+
+	// poll interval for waits that issue an HTTP request. the admin routes allow 10 req/s and
+	// the open ones 100 in tests, so this stays below the tighter of the two and the poll
+	// cannot manufacture the 429s it would then have to interpret
+	httpPoll = 150 * time.Millisecond
+)
+
+// waitForCount blocks until got reaches want, failing the test with the last value it saw.
+// for work that is delivered asynchronously, such as notifications reaching a mock destination
+func waitForCount(t *testing.T, want int, got func() int, msgAndArgs ...any) {
+	t.Helper()
+	require.EventuallyWithT(t, func(c *assert.CollectT) {
+		assert.Equal(c, want, got(), msgAndArgs...)
+	}, waitTimeout, pollInterval)
+}
+
+// waitForCountSettled waits for got to reach want and then holds it there, so a delivery
+// arriving late is caught rather than passing because the count was read the instant it matched
+func waitForCountSettled(t *testing.T, want int, got func() int, msgAndArgs ...any) {
+	t.Helper()
+	waitForCount(t, want, got, msgAndArgs...)
+	require.Never(t, func() bool { return got() != want }, notifySettle, pollInterval, msgAndArgs...)
+}
+
 // fake auth middleware make user authenticated and uses query's fake_id for ID and fake_name for Name
 func fakeAuth(next http.Handler) http.Handler {
 	fn := func(w http.ResponseWriter, r *http.Request) {
@@ -716,7 +743,7 @@ func get(t *testing.T, url string) (response string, statusCode int) {
 	return string(body), r.StatusCode
 }

-func sendReq(_ *testing.T, r *http.Request, tkn string) (*http.Response, error) {
+func sendReq(r *http.Request, tkn string) (*http.Response, error) {
 	client := http.Client{Timeout: 5 * time.Second}
 	defer client.CloseIdleConnections()
 	if tkn != "" {
@@ -798,7 +825,6 @@ func addCommentGetCreatedTime(t *testing.T, c store.Comment, ts *httptest.Server
 	crResp := R.JSON{}
 	err = json.Unmarshal(b, &crResp)
 	require.NoError(t, err)
-	time.Sleep(time.Nanosecond * 10)
 	created, err = time.Parse(time.RFC3339, crResp["time"].(string))
 	require.NoError(t, err)
 	return crResp["id"].(string), created
@@ -810,37 +836,41 @@ func addComment(t *testing.T, c store.Comment, ts *httptest.Server) string {
 }

 func requireAdminOnly(t *testing.T, req *http.Request) {
-	resp, err := sendReq(t, req, "") // no-auth user
+	resp, err := sendReq(req, "") // no-auth user
 	require.NoError(t, err)
 	require.NoError(t, resp.Body.Close())
 	assert.Equal(t, http.StatusUnauthorized, resp.StatusCode)

-	resp, err = sendReq(t, req, devToken) // non-admin user
+	resp, err = sendReq(req, devToken) // non-admin user
 	require.NoError(t, err)
 	require.NoError(t, resp.Body.Close())
 	assert.Equal(t, http.StatusForbidden, resp.StatusCode)
 }

-func chooseRandomUnusedPort() (port int) {
-	for range 10 {
-		port = 40000 + int(rand.Int31n(10000))
-		if ln, err := net.Listen("tcp", fmt.Sprintf(":%d", port)); err == nil {
-			_ = ln.Close()
-			break
-		}
-	}
+// chooseUnusedPort asks the kernel for a free port from the ephemeral range, which makes a
+// collision between concurrently running package test binaries very unlikely
+func chooseUnusedPort(t *testing.T) int {
+	t.Helper()
+	ln, err := net.Listen("tcp", ":0")
+	require.NoError(t, err, "no free port available")
+	port := ln.Addr().(*net.TCPAddr).Port
+	require.NoError(t, ln.Close())
 	return port
 }

-func waitForHTTPSServerStart(port int) {
-	// wait for up to 3 seconds for HTTPS server to start
-	for range 300 {
-		time.Sleep(time.Millisecond * 10)
-		conn, _ := net.DialTimeout("tcp", fmt.Sprintf("localhost:%d", port), time.Millisecond*10)
-		if conn != nil {
+// waitForServerStart blocks until something accepts on every listed port, failing the test
+// naming the port that never came up
+func waitForServerStart(t *testing.T, ports ...int) {
+	t.Helper()
+	for _, port := range ports {
+		require.Eventually(t, func() bool {
+			conn, err := net.DialTimeout("tcp", fmt.Sprintf("localhost:%d", port), probeDialTimeout)
+			if err != nil {
+				return false
+			}
 			_ = conn.Close()
-			break
-		}
+			return true
+		}, waitTimeout, pollInterval, "server on port %d didn't start", port)
 	}
 }

@@ -849,5 +879,9 @@ func TestMain(m *testing.M) {
 		m,
 		// this will be fixed in https://github.com/hashicorp/golang-lru/issues/159
 		goleak.IgnoreTopFunction("github.com/hashicorp/golang-lru/v2/expirable.NewLRU[...].func1"),
+		// regexp2, pulled in by chroma for syntax highlighting, keeps one shared clock goroutine
+		// alive for up to a second after the last match with a timeout, sleeping in 100ms ticks.
+		// it ends on its own, but a binary that finishes inside that window is reported as leaking
+		goleak.IgnoreAnyFunction("github.com/dlclark/regexp2/v2.runClock"),
 	)
 }
@@ -14,22 +14,29 @@ import (
 	"github.com/umputun/remark42/backend/app/store"
 )

+// rssPubTime returns a second-aligned base timestamp and formats it the way the feed does, so
+// comment pubDates are pinned rather than dependent on when in the second the test runs.
+func rssPubTime() (base time.Time, pubDate string) {
+	base = time.Now().Truncate(time.Second)
+	return base, base.Format(time.RFC1123Z)
+}
+
 func TestServer_RssPost(t *testing.T) {
 	ts, rst, teardown := startupT(t)
 	defer teardown()

-	waitOnSecChange()
+	base, pubDate := rssPubTime()

 	c1 := store.Comment{
-		ID:      "1234567890",
-		Text:    "test 123",
-		Locator: store.Locator{URL: "https://radio-t.com/blah1", SiteID: "remark42"},
-		User:    store.User{ID: "u1", Name: "developer one"},
+		ID:        "1234567890",
+		Text:      "test 123",
+		Timestamp: base,
+		Locator:   store.Locator{URL: "https://radio-t.com/blah1", SiteID: "remark42"},
+		User:      store.User{ID: "u1", Name: "developer one"},
 	}
 	id1, err := rst.DataService.Create(c1)
 	require.NoError(t, err)
 	assert.Equal(t, "1234567890", id1)
-	pubDate := time.Now().Format(time.RFC1123Z)

 	res, code := get(t, ts.URL+"/api/v1/rss/post?site=remark42&url=https://radio-t.com/blah1")
 	assert.Equal(t, http.StatusOK, code)
@@ -63,21 +70,21 @@ func TestServer_RssSite(t *testing.T) {
 	ts, rst, teardown := startupT(t)
 	defer teardown()

-	waitOnSecChange()
-
-	pubDate := time.Now().Format(time.RFC1123Z)
+	base, pubDate := rssPubTime()

 	c1 := store.Comment{
-		ID:      "comment-id-1",
-		Text:    "test 123",
-		Locator: store.Locator{URL: "https://radio-t.com/blah10", SiteID: "remark42"},
-		User:    store.User{ID: "u1", Name: "developer one"},
+		ID:        "comment-id-1",
+		Text:      "test 123",
+		Timestamp: base,
+		Locator:   store.Locator{URL: "https://radio-t.com/blah10", SiteID: "remark42"},
+		User:      store.User{ID: "u1", Name: "developer one"},
 	}
 	c2 := store.Comment{
-		ID:      "comment-id-2",
-		Text:    "xyz test",
-		Locator: store.Locator{URL: "https://radio-t.com/blah11", SiteID: "remark42"},
-		User:    store.User{ID: "u1", Name: "developer one"},
+		ID:        "comment-id-2",
+		Text:      "xyz test",
+		Timestamp: base.Add(time.Millisecond),
+		Locator:   store.Locator{URL: "https://radio-t.com/blah11", SiteID: "remark42"},
+		User:      store.User{ID: "u1", Name: "developer one"},
 	}

 	_, err := rst.DataService.Create(c1)
@@ -126,22 +133,22 @@ func TestServer_RssWithReply(t *testing.T) {
 	ts, rst, teardown := startupT(t)
 	defer teardown()

-	waitOnSecChange()
-
-	pubDate := time.Now().Format(time.RFC1123Z)
+	base, pubDate := rssPubTime()

 	c1 := store.Comment{
-		ID:      "comment-id-1",
-		Text:    "test 123",
-		Locator: store.Locator{URL: "https://radio-t.com/blah10", SiteID: "remark42"},
-		User:    store.User{ID: "u1", Name: "developer one"},
+		ID:        "comment-id-1",
+		Text:      "test 123",
+		Timestamp: base,
+		Locator:   store.Locator{URL: "https://radio-t.com/blah10", SiteID: "remark42"},
+		User:      store.User{ID: "u1", Name: "developer one"},
 	}
 	c2 := store.Comment{
-		ID:       "comment-id-2",
-		ParentID: "comment-id-1",
-		Text:     "xyz test",
-		Locator:  store.Locator{URL: "https://radio-t.com/blah10", SiteID: "remark42"},
-		User:     store.User{ID: "u1", Name: "developer one"},
+		ID:        "comment-id-2",
+		ParentID:  "comment-id-1",
+		Text:      "xyz test",
+		Timestamp: base.Add(time.Millisecond),
+		Locator:   store.Locator{URL: "https://radio-t.com/blah10", SiteID: "remark42"},
+		User:      store.User{ID: "u1", Name: "developer one"},
 	}

 	_, err := rst.DataService.Create(c1)
@@ -186,42 +193,45 @@ func TestServer_RssReplies(t *testing.T) {
 	ts, srv, teardown := startupT(t)
 	defer teardown()

-	waitOnSecChange()
-
-	pubDate := time.Now().Format(time.RFC1123Z)
+	base, pubDate := rssPubTime()

 	c1 := store.Comment{
-		ID:      "comment-1",
-		Text:    "c1",
-		Locator: store.Locator{URL: "https://radio-t.com/blah1", SiteID: "remark42"},
-		User:    store.User{ID: "user1", Name: "user1"},
+		ID:        "comment-1",
+		Text:      "c1",
+		Timestamp: base,
+		Locator:   store.Locator{URL: "https://radio-t.com/blah1", SiteID: "remark42"},
+		User:      store.User{ID: "user1", Name: "user1"},
 	}
 	c2 := store.Comment{
-		ID:       "comment-2",
-		Text:     "reply to c1 from user2",
-		ParentID: "comment-1",
-		Locator:  store.Locator{URL: "https://radio-t.com/blah1", SiteID: "remark42"},
-		User:     store.User{ID: "user2", Name: "user2"},
+		ID:        "comment-2",
+		Text:      "reply to c1 from user2",
+		ParentID:  "comment-1",
+		Timestamp: base.Add(time.Millisecond),
+		Locator:   store.Locator{URL: "https://radio-t.com/blah1", SiteID: "remark42"},
+		User:      store.User{ID: "user2", Name: "user2"},
 	}
 	c3 := store.Comment{
-		ID:       "comment-3",
-		Text:     "reply to c1 from user3",
-		ParentID: "comment-1",
-		Locator:  store.Locator{URL: "https://radio-t.com/blah1", SiteID: "remark42"},
-		User:     store.User{ID: "user3", Name: "user3"},
+		ID:        "comment-3",
+		Text:      "reply to c1 from user3",
+		ParentID:  "comment-1",
+		Timestamp: base.Add(2 * time.Millisecond),
+		Locator:   store.Locator{URL: "https://radio-t.com/blah1", SiteID: "remark42"},
+		User:      store.User{ID: "user3", Name: "user3"},
 	}
 	c4 := store.Comment{
-		ID:       "comment-4",
-		Text:     "reply to c2 from developer one",
-		ParentID: "comment-2",
-		Locator:  store.Locator{URL: "https://radio-t.com/blah1", SiteID: "remark42"},
-		User:     store.User{ID: "dev", Name: "developer one"},
+		ID:        "comment-4",
+		Text:      "reply to c2 from developer one",
+		ParentID:  "comment-2",
+		Timestamp: base.Add(3 * time.Millisecond),
+		Locator:   store.Locator{URL: "https://radio-t.com/blah1", SiteID: "remark42"},
+		User:      store.User{ID: "dev", Name: "developer one"},
 	}
 	c5 := store.Comment{
-		ID:      "comment-5",
-		Text:    "developer one",
-		Locator: store.Locator{URL: "https://radio-t.com/blah1", SiteID: "remark42"},
-		User:    store.User{ID: "dev", Name: "developer one"},
+		ID:        "comment-5",
+		Text:      "developer one",
+		Timestamp: base.Add(4 * time.Millisecond),
+		Locator:   store.Locator{URL: "https://radio-t.com/blah1", SiteID: "remark42"},
+		User:      store.User{ID: "dev", Name: "developer one"},
 	}

 	_, err := srv.DataService.Create(c1)
@@ -270,12 +280,6 @@ func TestServer_RssReplies(t *testing.T) {
 	assert.Equal(t, http.StatusBadRequest, code)
 }

-func waitOnSecChange() {
-	for time.Now().Nanosecond() >= 100000000 {
-		time.Sleep(10 * time.Nanosecond)
-	}
-}
-
 // clean formatting, i.e. multiple spaces, \t, \n
 func cleanRssFormatting(expected, actual string) (cleanExp, cleanAct string) {
 	reSpaces := regexp.MustCompile(`[\s\p{Zs}]{2,}`)