chore: clean up tests (#37715)

1. use MockVariableValue as much as possible
2. use wg.Go as much as possible instead of Add/Done
3. simplify global lock's DefaultLocker logic to make it easier to test
4. introduce a general approach for getting external service config in
CI
5. remove unclear & unnecessary "t.Skip"
6. use modern generic syntax for remaining "DecodeJSON" calls
7. clarify test result for "list gitignore templates" and "list
licenses"

tests/integration/repo_search_test.go

@@ -10,6 +10,7 @@ import (
 	repo_model "code.gitea.io/gitea/models/repo"
 	code_indexer "code.gitea.io/gitea/modules/indexer/code"
 	"code.gitea.io/gitea/modules/setting"
+	"code.gitea.io/gitea/modules/test"
 	"code.gitea.io/gitea/tests"
 
 	"github.com/PuerkitoBio/goquery"
@@ -35,8 +36,8 @@ func TestSearchRepo(t *testing.T) {
 
 	testSearch(t, "/user2/repo1/search?q=Description&page=1", []string{"README.md"})
 
-	setting.Indexer.IncludePatterns = setting.IndexerGlobFromString("**.txt")
-	setting.Indexer.ExcludePatterns = setting.IndexerGlobFromString("**/y/**")
+	defer test.MockVariableValue(&setting.Indexer.IncludePatterns, setting.IndexerGlobFromString("**.txt"))()
+	defer test.MockVariableValue(&setting.Indexer.ExcludePatterns, setting.IndexerGlobFromString("**/y/**"))()
 
 	repo, err = repo_model.GetRepositoryByOwnerAndName(t.Context(), "user2", "glob")
 	assert.NoError(t, err)