[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_helpers_test.go

@@ -13,7 +13,8 @@ import (
 )
 
 func TestGetTimeSortedPostAccessibleBounds(t *testing.T) {
-	var postFromCreateAt = func(at int64) *model.Post {
+	mainHelper.Parallel(t)
+	postFromCreateAt := func(at int64) *model.Post {
 		return &model.Post{CreateAt: at}
 	}
 
@@ -193,6 +194,7 @@ func TestGetTimeSortedPostAccessibleBounds(t *testing.T) {
 }
 
 func TestFilterInaccessiblePosts(t *testing.T) {
+	mainHelper.Parallel(t)
 	th := Setup(t)
 	th.App.Srv().SetLicense(model.NewTestLicense("cloud"))
 	err := th.App.Srv().Store().System().Save(&model.System{
@@ -203,7 +205,7 @@ func TestFilterInaccessiblePosts(t *testing.T) {
 
 	defer th.TearDown()
 
-	var postFromCreateAt = func(at int64) *model.Post {
+	postFromCreateAt := func(at int64) *model.Post {
 		return &model.Post{CreateAt: at}
 	}
 
@@ -322,6 +324,7 @@ func TestFilterInaccessiblePosts(t *testing.T) {
 }
 
 func TestGetFilteredAccessiblePosts(t *testing.T) {
+	mainHelper.Parallel(t)
 	th := Setup(t)
 	th.App.Srv().SetLicense(model.NewTestLicense("cloud"))
 	err := th.App.Srv().Store().System().Save(&model.System{
@@ -332,7 +335,7 @@ func TestGetFilteredAccessiblePosts(t *testing.T) {
 
 	defer th.TearDown()
 
-	var postFromCreateAt = func(at int64) *model.Post {
+	postFromCreateAt := func(at int64) *model.Post {
 		return &model.Post{CreateAt: at}
 	}
 
@@ -364,6 +367,7 @@ func TestGetFilteredAccessiblePosts(t *testing.T) {
 }
 
 func TestIsInaccessiblePost(t *testing.T) {
+	mainHelper.Parallel(t)
 	th := Setup(t)
 	th.App.Srv().SetLicense(model.NewTestLicense("cloud"))
 	err := th.App.Srv().Store().System().Save(&model.System{
@@ -386,6 +390,7 @@ func TestIsInaccessiblePost(t *testing.T) {
 }
 
 func Test_getInaccessibleRange(t *testing.T) {
+	mainHelper.Parallel(t)
 	type test struct {
 		label         string
 		bounds        accessibleBounds