package main

import (
	"errors"
	"testing"

	"github.com/novox/mesh-controller/internal/link"
)

// **A merge whose plan could not be saved is held, never taken** (novox/hq ADR 0407 decision 3, issue 1092): the merge is
// carried until its plan is saved, and the bus acknowledges the announcement only when the controller answers without
// ErrTryAgain (link.Server.sourceMoved), so a failed save of any kind must answer it.
func TestAFailureToSaveAMergesPlanIsHeldAndNotTaken(t *testing.T) {
	cause := errors.New("the plan for novox/mesh-catalog is not written: the plan was written by somebody else since it was read")
	held := unsaved(cause)
	if !errors.Is(held, link.ErrTryAgain) || !errors.Is(held, cause) {
		t.Fatalf("a failed save answers %v", held)
	}
	if unsaved(nil) != nil {
		t.Fatal("a save that worked answers an error")
	}
	// Not the same as notNow, which holds a merge only for a store that is away.
	if errors.Is(notNow(cause), link.ErrTryAgain) {
		t.Fatal("notNow holds every failure; the premise of this test is gone")
	}
}