[MM-62408] Server Code Coverage with Fully Parallel Tests (#30078)

* TestPool

* Store infra

* Store tests updates

* Bump maximum concurrent postgres connections

* More infra

* channels/jobs

* channels/app

* channels/api4

* Protect i18n from concurrent access

* Replace some use of os.Setenv

* Remove debug

* Lint fixes

* Fix more linting

* Fix test

* Remove use of Setenv in drafts tests

* Fix flaky TestWebHubCloseConnOnDBFail

* Fix merge

* [MM-62408] Add CI job to generate test coverage (#30284)

* Add CI job to generate test coverage

* Remove use of Setenv in drafts tests

* Fix flaky TestWebHubCloseConnOnDBFail

* Fix more Setenv usage

* Fix more potential flakyness

* Remove parallelism from flaky test

* Remove conflicting env var

* Fix

* Disable parallelism

* Test atomic covermode

* Disable parallelism

* Enable parallelism

* Add upload coverage step

* Fix codecov.yml

* Add codecov.yml

* Remove redundant workspace field

* Add Parallel() util methods and refactor

* Fix formatting

* More formatting fixes

* Fix reporting

server/channels/app/post_metadata_test.go

@@ -37,6 +37,7 @@ import (
 )
 
 func TestPreparePostListForClient(t *testing.T) {
+	mainHelper.Parallel(t)
 	// Most of this logic is covered by TestPreparePostForClient, so this just tests handling of multiple posts
 
 	th := Setup(t)
@@ -68,6 +69,7 @@ func TestPreparePostListForClient(t *testing.T) {
 }
 
 func TestPreparePostForClient(t *testing.T) {
+	mainHelper.Parallel(t)
 	var serverURL string
 	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		switch r.URL.Path {
@@ -862,6 +864,7 @@ func TestPreparePostForClient(t *testing.T) {
 }
 
 func TestPreparePostForClientWithImageProxy(t *testing.T) {
+	mainHelper.Parallel(t)
 	setup := func(t *testing.T) *TestHelper {
 		th := Setup(t).InitBasic()
 
@@ -981,6 +984,7 @@ func testProxyOpenGraphImage(t *testing.T, th *TestHelper, shouldProxy bool) {
 }
 
 func TestGetEmbedForPost(t *testing.T) {
+	mainHelper.Parallel(t)
 	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		if r.URL.Path == "/index.html" {
 			w.Header().Set("Content-Type", "text/html")
@@ -1157,6 +1161,7 @@ func TestGetEmbedForPost(t *testing.T) {
 }
 
 func TestGetImagesForPost(t *testing.T) {
+	mainHelper.Parallel(t)
 	t.Run("with an image link", func(t *testing.T) {
 		th := Setup(t)
 		defer th.TearDown()
@@ -1445,6 +1450,7 @@ func TestGetImagesForPost(t *testing.T) {
 }
 
 func TestGetEmojiNamesForString(t *testing.T) {
+	mainHelper.Parallel(t)
 	testCases := []struct {
 		Description string
 		Input       string
@@ -1496,6 +1502,7 @@ func TestGetEmojiNamesForString(t *testing.T) {
 }
 
 func TestGetEmojiNamesForPost(t *testing.T) {
+	mainHelper.Parallel(t)
 	testCases := []struct {
 		Description string
 		Post        *model.Post
@@ -1591,6 +1598,7 @@ func TestGetEmojiNamesForPost(t *testing.T) {
 }
 
 func TestGetCustomEmojisForPost(t *testing.T) {
+	mainHelper.Parallel(t)
 	th := Setup(t).InitBasic()
 	defer th.TearDown()
 
@@ -1670,6 +1678,7 @@ func TestGetCustomEmojisForPost(t *testing.T) {
 }
 
 func TestGetFirstLinkAndImages(t *testing.T) {
+	mainHelper.Parallel(t)
 	th := Setup(t).InitBasic()
 	defer th.TearDown()
 
@@ -1838,6 +1847,7 @@ func TestGetFirstLinkAndImages(t *testing.T) {
 }
 
 func TestGetImagesInMessageAttachments(t *testing.T) {
+	mainHelper.Parallel(t)
 	th := Setup(t).InitBasic()
 	defer th.TearDown()
 
@@ -2623,6 +2633,7 @@ func TestGetLinkMetadata(t *testing.T) {
 }
 
 func TestResolveMetadataURL(t *testing.T) {
+	mainHelper.Parallel(t)
 	for _, test := range []struct {
 		Name       string
 		RequestURL string
@@ -2664,6 +2675,7 @@ func TestResolveMetadataURL(t *testing.T) {
 }
 
 func TestParseLinkMetadata(t *testing.T) {
+	mainHelper.Parallel(t)
 	th := Setup(t)
 	defer th.TearDown()
 
@@ -2760,6 +2772,7 @@ func TestParseLinkMetadata(t *testing.T) {
 }
 
 func TestParseImages(t *testing.T) {
+	mainHelper.Parallel(t)
 	for name, testCase := range map[string]struct {
 		FileName    string
 		Expected    *model.PostImage
@@ -2879,6 +2892,7 @@ func TestParseImages(t *testing.T) {
 }
 
 func TestLooksLikeAPermalink(t *testing.T) {
+	mainHelper.Parallel(t)
 	const siteURLWithSubpath = "http://localhost:8065/foo"
 	const siteURLWithTrailingSlash = "http://test.com/"
 	const siteURL = "http://test.com"
@@ -2910,6 +2924,7 @@ func TestLooksLikeAPermalink(t *testing.T) {
 }
 
 func TestContainsPermalink(t *testing.T) {
+	mainHelper.Parallel(t)
 	th := Setup(t)
 	defer th.TearDown()
 
@@ -2949,6 +2964,7 @@ func TestContainsPermalink(t *testing.T) {
 }
 
 func TestSanitizePostMetadataForUserAndChannel(t *testing.T) {
+	mainHelper.Parallel(t)
 	th := Setup(t).InitBasic()
 	defer th.TearDown()
 
@@ -3073,6 +3089,7 @@ func TestSanitizePostMetadataForUserAndChannel(t *testing.T) {
 }
 
 func TestSanitizePostMetaDataForAudit(t *testing.T) {
+	mainHelper.Parallel(t)
 	th := Setup(t).InitBasic()
 	defer th.TearDown()
 
@@ -3125,6 +3142,7 @@ func TestSanitizePostMetaDataForAudit(t *testing.T) {
 }
 
 func TestSanitizePostMetadataForUser(t *testing.T) {
+	mainHelper.Parallel(t)
 	th := Setup(t).InitBasic()
 	defer th.TearDown()