mesh-controller/cmd/mesh-controller/holdings_test.go

package main

import (
	"strings"
	"testing"

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

// A seat nobody ever handed over is held by whichever assignment happened to be alone — and the
// day a second module able to hold it is assigned, both claimed, both were refused, and the first
// one's machine stopped resolving (novox/hq 04-ISSUES/170). The mesh now writes the derived holder
// down before it acts, so the second assignment stands beside the holder on record.

func aSeatedStore() catalogue.Manifest {
	return catalogue.Manifest{Module: "store", Version: "1",
		Provides: []catalogue.Offer{{Name: "postgres-database", Scope: catalogue.ScopeMesh}},
		Serves:   map[string]map[string]any{"postgres-database": {"port": 5432}},
		Claims:   []catalogue.Claim{{Name: "mesh-store", Scope: catalogue.ScopeMesh}}}
}

func TestASecondEligibleHolderStandsBesideTheOneHeldByBeingAlone(t *testing.T) {
	open := aMesh(t)
	ctx := t.Context()
	// Every deploy seeds the mesh's own seats; a record is a row against one of them.
	if _, err := open.inventory.SeedSeats(ctx, catalogue.DefaultSeats()); err != nil {
		t.Fatal(err)
	}
	register(t, open, aSeatedStore())

	if _, err := assign(ctx, open, "anchor", "store"); err != nil {
		t.Fatal(err)
	}
	said, err := assign(ctx, open, "laptop", "store")
	if err != nil {
		t.Fatalf("a second store, eligible for the seat, was refused:\n%s\n%v", said, err)
	}
	if strings.Contains(said, "cannot be worked out") {
		t.Fatalf("assigning a second store unsettled the first one's machine:\n%s", said)
	}
	if !strings.Contains(said, "recorded store on anchor as the standing holder of mesh-store") {
		t.Fatalf("the holder by derivation was not written down:\n%s", said)
	}

	holdings, err := open.inventory.Holdings(ctx)
	if err != nil {
		t.Fatal(err)
	}
	var found bool
	for _, h := range holdings {
		if h.Claim == "mesh-store" {
			found = true
			if h.Node != "anchor" || h.Module != "store" {
				t.Fatalf("mesh-store is recorded on %s/%s, not on the one that held it", h.Node, h.Module)
			}
		}
	}
	if !found {
		t.Fatalf("mesh-store has no holder on record after assigning: %v", holdings)
	}

	// And the record decides from here: the anchor's plan holds the seat, the laptop's does not.
	for node, holds := range map[string]bool{"anchor": true, "laptop": false} {
		plan, _, err := planFor(ctx, open, node)
		if err != nil {
			t.Fatalf("%s no longer resolves: %v", node, err)
		}
		var claimed bool
		for _, c := range plan.Claims {
			if c.Claim == "mesh-store" {
				claimed = true
			}
		}
		if claimed != holds {
			t.Fatalf("%s holds mesh-store: %v, want %v", node, claimed, holds)
		}
	}
}

func TestAHolderOnRecordIsNotRewrittenByDerivation(t *testing.T) {
	open := aMesh(t)
	ctx := t.Context()
	if _, err := open.inventory.SeedSeats(ctx, catalogue.DefaultSeats()); err != nil {
		t.Fatal(err)
	}
	register(t, open, aSeatedStore())
	for _, node := range []string{"anchor", "laptop"} {
		if _, err := assign(ctx, open, node, "store"); err != nil {
			t.Fatal(err)
		}
	}
	// A person hands the seat to the laptop. From here the record decides, and what the mesh
	// derives must never write over it.
	if err := open.inventory.HoldSeat(ctx, "mesh-store", catalogue.ScopeMesh, "laptop", "store"); err != nil {
		t.Fatal(err)
	}
	said, err := recordDerivedHolders(ctx, open)
	if err != nil {
		t.Fatal(err)
	}
	if len(said) != 0 {
		t.Fatalf("a seat on record was written again from derivation: %v", said)
	}
	holdings, _ := open.inventory.Holdings(ctx)
	for _, h := range holdings {
		if h.Claim == "mesh-store" && h.Node != "laptop" {
			t.Fatalf("the record moved to %s", h.Node)
		}
	}
}