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/branches_test.go

@@ -12,6 +12,7 @@ import (
 	"code.gitea.io/gitea/tests"
 
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
 func TestViewBranches(t *testing.T) {
@@ -57,9 +58,7 @@ func branchAction(t *testing.T, button string) (*HTMLDoc, string) {
 
 	htmlDoc := NewHTMLParser(t, resp.Body)
 	link, exists := htmlDoc.doc.Find(button).Attr("data-url")
-	if !assert.True(t, exists, "The template has changed") {
-		t.Skip()
-	}
+	require.True(t, exists, "The template has changed")
 
 	req = NewRequest(t, "POST", link)
 	session.MakeRequest(t, req, http.StatusOK)