Give every module the announcement test, on an exported test bus (issue 1790, S11, ADR 0495 §5)

announcetest.Check starts the module against a bus of the test's own and holds its
announcement equal to what its code declares; testbus leaves internal/ so a module's
own integration tests can start it.

go/announcetest/announcetest.go

@@ -0,0 +1,91 @@
+// Package announcetest is the test each module runs with its own checks to hold that it announces on the bus every
+// state it keeps (novox/hq ADR 0495 clause 5; issue 1790): it starts the module against a bus of the test's own and
+// compares what the module announced with what its code declares. With the bind guard of process.Conn.Keeps,
+// stdio.Keeps and the TypeScript keeps, which refuses a state the code did not announce, announcement and code agree.
+//
+// It replaces the merge gate's check of one module's reads against another's manifest (clause 5); a test using it
+// carries `//go:build integration`, since it starts a bus.
+package announcetest
+
+import (
+	"context"
+	"fmt"
+	"reflect"
+	"sort"
+	"testing"
+	"time"
+
+	"github.com/nats-io/nats.go"
+	"github.com/nats-io/nats.go/jetstream"
+
+	"git.novox.be/novox/mesh-sdk/go/announce"
+	"git.novox.be/novox/mesh-sdk/go/testbus"
+)
+
+// Wait is how long Check waits for the module's announcement once it started it.
+var Wait = 10 * time.Second
+
+// Check starts a bus of the test's own, with a stream taking module's events, calls start with its address (start
+// runs the module, or its part that connects, against it, and answers how to stop it), waits for the module's
+// announcement and fails the test unless it is module's and names exactly want (in any order), readable as want says.
+// It answers the announcement.
+func Check(t testing.TB, module string, want []announce.State, start func(url string) (stop func())) announce.States {
+	t.Helper()
+	url := testbus.URL(t)
+	nc, err := nats.Connect(url)
+	if err != nil {
+		t.Fatalf("announcetest: connecting to the test bus: %v", err)
+	}
+	defer nc.Close()
+	js, err := jetstream.New(nc)
+	if err != nil {
+		t.Fatal(err)
+	}
+	ctx, cancel := context.WithTimeout(context.Background(), Wait)
+	defer cancel()
+	stream, err := js.CreateStream(ctx, jetstream.StreamConfig{Name: "ANNOUNCETEST", Subjects: []string{"mesh.mod." + module + ".event.>"}})
+	if err != nil {
+		t.Fatalf("announcetest: making the events stream: %v", err)
+	}
+	stop := start(url)
+	if stop != nil {
+		defer stop()
+	}
+	got, err := waitFor(ctx, stream, module)
+	if err != nil {
+		t.Fatalf("announcetest: %v", err)
+	}
+	if problem := differs(got, module, want); problem != "" {
+		t.Fatalf("announcetest: %s", problem)
+	}
+	return got
+}
+
+// waitFor reads the stream until module's announcement is in it.
+func waitFor(ctx context.Context, stream jetstream.Stream, module string) (announce.States, error) {
+	for {
+		msg, err := stream.GetLastMsgForSubject(ctx, announce.Subject(module))
+		if err == nil {
+			return announce.Decode(msg.Data)
+		}
+		select {
+		case <-ctx.Done():
+			return announce.States{}, fmt.Errorf("%s announced nothing on %s within %s", module, announce.Subject(module), Wait)
+		case <-time.After(50 * time.Millisecond):
+		}
+	}
+}
+
+// differs says how got is not module's announcement of want, or "".
+func differs(got announce.States, module string, want []announce.State) string {
+	if got.Module != module {
+		return fmt.Sprintf("the announcement names the module %q, not %q", got.Module, module)
+	}
+	w := append([]announce.State{}, want...)
+	sort.Slice(w, func(i, j int) bool { return w[i].Name < w[j].Name })
+	g := append([]announce.State{}, got.States...)
+	if !reflect.DeepEqual(g, w) && !(len(g) == 0 && len(w) == 0) {
+		return fmt.Sprintf("%s announced %v, and its code declares %v", module, g, w)
+	}
+	return ""
+}

go/announcetest/announcetest_integration_test.go

@@ -0,0 +1,29 @@
+//go:build integration
+
+package announcetest
+
+import (
+	"testing"
+
+	"git.novox.be/novox/mesh-sdk/go/announce"
+	"git.novox.be/novox/mesh-sdk/go/process"
+)
+
+// 1790/S11: a module started against the test bus announces through process.Conn.Keeps, and Check reads that
+// announcement back against what the code declares.
+func TestCheckReadsTheModulesAnnouncementOffARealBus(t *testing.T) {
+	declared := []announce.State{{Name: "accounts", Readable: true}, {Name: "drafts"}}
+	got := Check(t, "mesh-mail", declared, func(url string) func() {
+		conn, err := process.Connect(process.Account{URL: url, Module: "mesh-mail", Node: "novox", User: "u", Password: "p"})
+		if err != nil {
+			t.Fatal(err)
+		}
+		if err := conn.Keeps(declared...); err != nil {
+			t.Fatal(err)
+		}
+		return conn.Close
+	})
+	if got.Node != "novox" {
+		t.Fatalf("announced from %q", got.Node)
+	}
+}

go/announcetest/announcetest_test.go

@@ -0,0 +1,32 @@
+package announcetest
+
+import (
+	"strings"
+	"testing"
+
+	"git.novox.be/novox/mesh-sdk/go/announce"
+)
+
+// The comparison is exact up to order: a state missing, one extra, a readability that differs or another module's
+// announcement each fail, naming what differs.
+func TestAnAnnouncementDiffersFromTheCodeByNameAndReadability(t *testing.T) {
+	got := announce.States{Module: "m", States: []announce.State{{Name: "a", Readable: true}, {Name: "b"}}}
+	if p := differs(got, "m", []announce.State{{Name: "b"}, {Name: "a", Readable: true}}); p != "" {
+		t.Fatalf("an equal announcement differs: %s", p)
+	}
+	for _, want := range [][]announce.State{
+		{{Name: "a", Readable: true}},
+		{{Name: "a", Readable: true}, {Name: "b"}, {Name: "c"}},
+		{{Name: "a"}, {Name: "b"}},
+	} {
+		if p := differs(got, "m", want); p == "" || !strings.Contains(p, "declares") {
+			t.Errorf("want %v: %q", want, p)
+		}
+	}
+	if p := differs(got, "other", nil); !strings.Contains(p, `"other"`) {
+		t.Errorf("another module's announcement: %q", p)
+	}
+	if p := differs(announce.States{Module: "m"}, "m", nil); p != "" {
+		t.Errorf("a module keeping nothing: %q", p)
+	}
+}

go/merge-check.sh

@@ -10,7 +10,7 @@
 #   1. the unit level: `go test ./...` untagged, no bus or other process, timed and held to a bound
 #      (unit_bound below); over it the check fails and names the slowest tests (issue 895);
 #   2. the integration level: the whole suite with `-tags integration`, each test against a bus of its
-#      own (internal/testbus, which issue 1171 brings with the first test that needs a bus) so nothing is
+#      own (testbus, which issue 1171 brings with the first test that needs a bus) so nothing is
 #      serialised. With no tagged test yet, the level runs the unit tests again and says their count.
 #
 # **A test that starts a bus or another process carries `//go:build integration`** as the first line of
@@ -117,7 +117,7 @@ if [ "$status" -ne 0 ]; then
 fi
 judge_unit_run "$work/unit.out" "$unit_bound"
 
-# The integration level: the whole suite with the tag, each test against its own bus (internal/testbus).
+# The integration level: the whole suite with the tag, each test against its own bus (testbus).
 integration_start=$(date +%s)
 status=0
 go test -tags integration -count=1 -v ./... >"$work/integration.out" 2>&1 || status=$?

go/process/conn_integration_test.go

@@ -22,7 +22,7 @@ import (
 )
 
 // selfSignedServer is a nats-server with JetStream and TLS, self-signed, for this test alone (mirroring
-// go/internal/testbus.Start, with a certificate added since testbus has none): a mesh's bus presents its own
+// go/testbus.Start, with a certificate added since testbus has none): a mesh's bus presents its own
 // certificate in no public trust store, which is exactly what a process pins to (ADR 0436 clause 4).
 func selfSignedServer(t *testing.T) (url, fingerprint string) {
 	t.Helper()

go/testbus/testbus.go

@@ -1,5 +1,7 @@
 // Package testbus is the bus an integration test of the SDK's Go binding runs against: a server of
-// its own, of the release go.mod pins, started for the one test and gone after it.
+// its own, of the release go.mod pins, started for the one test and gone after it. It is exported so a
+// module's own integration tests start against the same (announcetest, novox/hq ADR 0495 clause 5;
+// issue 1182 names the controller's copy).
 //
 // **Why one per test.** A test that reaches a shared bus asserts, reads and removes objects by fixed
 // name — a stream, a consumer — and two tests at once would step on each other's: one deleting what