mesh-controller/internal/catalogue/seats_declared_test.go

package catalogue

import (
	"strings"
	"testing"
)

func problemsFor(t *testing.T, shelf Shelf) string {
	t.Helper()
	return strings.Join(CatalogueProblems(shelf), "; ")
}

func telegram() Manifest {
	return Manifest{Module: "telegram", Tools: []string{"status"}, DefinesSeats: []SeatDeclaration{{
		Name: "telegram-sender", Scope: ScopeMesh,
		Accepts: []string{"send"}, Emits: []string{"delivered", "failed"}, Serves: []Verb{{Name: "status"}},
	}}, Claims: []Claim{{Name: "telegram-sender", Scope: ScopeMesh}}}
}

// The whole point: a module contributes a capability without the mesh being changed.
func TestAModuleDeclaresItsOwnSeatAndHoldsIt(t *testing.T) {
	shop := Manifest{Module: "shop", Uses: []string{"telegram-sender"}}
	if got := problemsFor(t, Shelf{"telegram": telegram(), "shop": shop}); got != "" {
		t.Fatalf("a declared seat and its caller were refused: %s", got)
	}
}

// The prefix is the reservation rule, so there is no list to maintain and none to drift.
func TestAModuleCannotDeclareAMeshSeat(t *testing.T) {
	for _, n := range []string{"mesh-broker", "mesh-anything", "mesh-store"} {
		m := Manifest{Module: "impostor", DefinesSeats: []SeatDeclaration{{Name: n, Accepts: []string{"x"}}}}
		got := strings.Join(declaredSeatProblems(m), "; ")
		if !strings.Contains(got, "reserved to the mesh") {
			t.Fatalf("%q was accepted as a module's seat: %q", n, got)
		}
	}
}

// A seat name meaning two protocols is the failure nobody could diagnose afterwards.
func TestTwoModulesCannotDeclareTheSameSeat(t *testing.T) {
	other := Manifest{Module: "aardvark", DefinesSeats: []SeatDeclaration{{
		Name: "telegram-sender", Scope: ScopeMesh, Accepts: []string{"something-else"}}}}
	got := problemsFor(t, Shelf{"telegram": telegram(), "aardvark": other})
	if !strings.Contains(got, "already declares") {
		t.Fatalf("both declarations stood: %s", got)
	}
	// The first declarer keeps it; only the second is refused.
	if strings.Count(got, "already declares") != 1 {
		t.Fatalf("expected exactly one refusal: %s", got)
	}
}

// Where ADR 0110's guarantee lands under a derived set: a typo is refused, not resolved to
// nothing at runtime.
func TestUsingASeatNobodyDeclaresIsRefused(t *testing.T) {
	shop := Manifest{Module: "shop", Uses: []string{"telegram-sendr"}}
	got := problemsFor(t, Shelf{"telegram": telegram(), "shop": shop})
	if !strings.Contains(got, "telegram-sendr") || !strings.Contains(got, "no module declares") {
		t.Fatalf("a misspelled seat was accepted: %s", got)
	}
}

// A holder that does not answer what the seat promises is a caller's timeout, found here instead.
func TestAHolderMustServeWhatItsSeatPromises(t *testing.T) {
	m := telegram()
	m.Tools = nil // declares the seat, serves none of it
	got := problemsFor(t, Shelf{"telegram": m})
	if !strings.Contains(got, "does not serve status") {
		t.Fatalf("a holder was accepted that answers nothing its seat promises: %s", got)
	}
}

// The claim may say what it serves for the role instead, when the module's own tools are not the
// seat's verbs (ADR 0160).
func TestAClaimMayNameWhatItServesForTheSeat(t *testing.T) {
	m := telegram()
	m.Tools = []string{"telegram_send"}
	m.Claims = append([]Claim(nil), m.Claims...)
	for i := range m.Claims {
		if m.Claims[i].Name == "telegram-sender" {
			m.Claims[i].Serves = []string{"status"}
		}
	}
	if got := problemsFor(t, Shelf{"telegram": m}); strings.Contains(got, "does not serve") {
		t.Fatalf("a claim naming the seat's verb was refused: %s", got)
	}
}

// A seat with no protocol is a marker: which module is this node's showcase, or its packet filter.
// Most node-scoped seats are markers, so refusing one would refuse the majority of the set.
func TestASeatWithoutAProtocolIsAMarkerNotAMistake(t *testing.T) {
	m := Manifest{Module: "vague", DefinesSeats: []SeatDeclaration{{Name: "something", Scope: ScopeNode}}}
	if got := strings.Join(declaredSeatProblems(m), "; "); got != "" {
		t.Fatalf("a marker seat was refused: %s", got)
	}
}

// A claim at the wrong scope is a different seat than the one declared.
func TestAClaimMustMatchTheDeclaredScope(t *testing.T) {
	m := telegram()
	m.Claims = []Claim{{Name: "telegram-sender", Scope: ScopeNode}}
	got := problemsFor(t, Shelf{"telegram": m})
	if !strings.Contains(got, "scope") {
		t.Fatalf("a claim at the wrong scope was accepted: %s", got)
	}
}

// The mesh's own seats still work, and are not shadowed by the derived half.
func TestTheMeshsOwnSeatsAreStillClaimable(t *testing.T) {
	// It delivers the bus, so its holder provides the bus — the rule this check now enforces.
	m := Manifest{Module: "nats",
		Provides: []Offer{{Name: "mesh-bus", Scope: ScopeMesh}},
		Claims:   []Claim{{Name: "mesh-broker", Scope: ScopeMesh}}}
	if got := problemsFor(t, Shelf{"nats": m}); got != "" {
		t.Fatalf("a mesh seat was refused by the derived check: %s", got)
	}
}

// Only a node seat may carry needs (novox/hq ADR 0378 §8): a per-mesh seat's holder is not on any
// one node to depend on anything beside it there.
func TestOnlyANodeSeatMayCarryNeeds(t *testing.T) {
	m := Manifest{Module: "mail", DefinesSeats: []SeatDeclaration{{
		Name: "mail-notifier", Scope: ScopeMesh, Needs: []string{"node-notifier"}}}}
	got := strings.Join(declaredSeatProblems(m), "; ")
	if !strings.Contains(got, "needing") || !strings.Contains(got, "node seat") {
		t.Fatalf("a mesh-scope seat's needs were accepted: %q", got)
	}
}

// A seat needing itself names nothing (novox/hq ADR 0378 §8).
func TestASeatCannotNeedItself(t *testing.T) {
	m := Manifest{Module: "mail", DefinesSeats: []SeatDeclaration{{
		Name: "mail-notifier", Scope: ScopeNode, Needs: []string{"mail-notifier"}}}}
	got := strings.Join(declaredSeatProblems(m), "; ")
	if !strings.Contains(got, "needing itself") {
		t.Fatalf("a seat needing itself was accepted: %q", got)
	}
}

// A need naming nothing node-scope — undeclared, or declared at another scope — is the whole
// catalogue's to say (novox/hq ADR 0378 §8).
func TestANeedMustNameANodeSeatSomewhereInTheCatalogue(t *testing.T) {
	mail := Manifest{Module: "mail", DefinesSeats: []SeatDeclaration{{
		Name: "mail-notifier", Scope: ScopeNode, Needs: []string{"desk-beeper"}}}}

	// Nobody declares desk-beeper at all.
	got := problemsFor(t, Shelf{"mail": mail})
	if !strings.Contains(got, "desk-beeper") || !strings.Contains(got, "no module declares") {
		t.Fatalf("needing an undeclared seat was accepted: %q", got)
	}

	// Declared, but at mesh scope: still not a node seat to hold beside it.
	notNode := Manifest{Module: "dunst", DefinesSeats: []SeatDeclaration{{Name: "desk-beeper", Scope: ScopeMesh}}}
	got = problemsFor(t, Shelf{"mail": mail, "dunst": notNode})
	if !strings.Contains(got, "desk-beeper") || !strings.Contains(got, "not a node seat") {
		t.Fatalf("needing a mesh-scope seat was accepted: %q", got)
	}

	// Declared at node scope: accepted.
	dunst := Manifest{Module: "dunst", DefinesSeats: []SeatDeclaration{{Name: "desk-beeper", Scope: ScopeNode}}}
	if got := problemsFor(t, Shelf{"mail": mail, "dunst": dunst}); got != "" {
		t.Fatalf("needing a node seat another module declares was refused: %q", got)
	}
}

// A refusal that reorders itself between runs is a refusal nobody can diff.
func TestTheProblemsAreStable(t *testing.T) {
	shelf := Shelf{"telegram": telegram(), "shop": {Module: "shop", Uses: []string{"nope"}},
		"other": {Module: "other", Uses: []string{"also-nope"}}}
	first, second := problemsFor(t, shelf), problemsFor(t, shelf)
	if first != second {
		t.Fatalf("unstable:\n%s\n%s", first, second)
	}
}

// **A build machine has no store, so it may not judge a seat.** The set is data the control plane
// owns (novox/hq ADR 0122), and `ParseManifest` runs on the build machine too, against whatever set
// that binary was compiled with. When the two disagreed, a valid holder of the bus seat was refused
// mid-rollout — the compiled row said the seat delivered one provision, the store's row said
// another, and the build failed on the copy rather than the truth. The parser judges the manifest;
// the seat set judges the claim, where it is loaded.
func TestTheParserDoesNotJudgeWhatOnlyTheStoreKnows(t *testing.T) {
	was := Seats()
	t.Cleanup(func() { UseSeats(was) })

	// A store whose bus seat delivers something this module does provide.
	UseSeats([]Seat{{Name: "mesh-broker", Scope: ScopeMesh, Delivers: "mesh-bus", Decision: "test"}})
	raw := []byte(`{"module":"a-bus","version":"1",` +
		`"provides":[{"name":"mesh-bus","scope":"mesh"}],` +
		`"claims":[{"name":"mesh-broker","scope":"mesh"}]}`)

	m, err := ParseManifest(raw)
	if err != nil {
		t.Fatalf("the parser refused a claim only the seat set can judge: %v", err)
	}
	if got := CatalogueProblems(Shelf{m.Module: m}); len(got) != 0 {
		t.Fatalf("a holder that provides what the store says the seat delivers was refused: %v", got)
	}

	// And with the store saying the seat delivers something else, registration is what refuses it.
	UseSeats([]Seat{{Name: "mesh-broker", Scope: ScopeMesh, Delivers: "other-bus", Decision: "test"}})
	if _, err := ParseManifest(raw); err != nil {
		t.Fatalf("the parser judged it the second time: %v", err)
	}
	got := strings.Join(CatalogueProblems(Shelf{m.Module: m}), "; ")
	if !strings.Contains(got, `does not provide "other-bus"`) {
		t.Fatalf("registration did not refuse a holder that cannot answer for the seat: %q", got)
	}
}