build: implement a framework for starting test servers during tests

Test servers are implemented by docker containers and run real servers
for rclone to test against.

fstest/test_all/run.go

@@ -22,6 +22,7 @@ import (
 	"time"
 
 	"github.com/rclone/rclone/fs"
+	"github.com/rclone/rclone/fstest/testserver"
 )
 
 // Control concurrency per backend if required
@@ -213,6 +214,16 @@ func (r *Run) trial() {
 		return
 	}
 
+	// Start the test server if required
+	finish, err := testserver.Start(r.Remote)
+	if err != nil {
+		log.Printf("%s: Failed to start test server: %v", r.Remote, err)
+		_, _ = fmt.Fprintf(out, "%s: Failed to start test server: %v\n", r.Remote, err)
+		r.err = err
+		return
+	}
+	defer finish()
+
 	// Internal buffer
 	var b bytes.Buffer
 	multiOut := io.MultiWriter(out, &b)