C3: the engine-reads keeper keeps the fallback or the last statement at the first fault while the kept call asks on (issue 1966, ADR 0668 §3; review round 1, finding 1)

A part whose node answers nothing waited out busretry.Bound (30 s) before it acted on the node's record: Once asks the verb once, and its fault is taken at once.

Claude-Session: https://claude.ai/code/session_01JG73KEq4zoDfM9WtYpcQgZ

go/clients/nodeengineclient/enginereads/enginereads_test.go

@@ -3,6 +3,7 @@ package enginereads
 import (
 	"context"
 	"encoding/json"
+	"errors"
 	"strings"
 	"testing"
 	"time"
@@ -55,6 +56,21 @@ func TestTheAnswerAndTheEventAreJudged(t *testing.T) {
 	if p := k.Present([]string{"ace", "g14"}); len(p["ace"]) != 1 || len(p["g14"]) != 1 || calls["ace"] != 2 || calls["g14"] != 1 {
 		t.Errorf("after the bind: present %v, calls %v", p, calls)
 	}
+	// Review round 1 (ADR 0668 §3): a node whose engine answers nothing reads as its record at the first fault of the call
+	// made once, while the kept call asks on; what the kept call answers then stands.
+	var during Statement
+	f := &Keeper{Sync: true, Fallback: func(string) ([]string, bool) { return []string{"r.s"}, true },
+		Once: func(string, string, any) (json.RawMessage, error) {
+			return nil, errors.New("nats: no responders available for request")
+		}}
+	f.Call = func(node, _ string, _ any) (json.RawMessage, error) {
+		during = f.Statements()[node]
+		return json.RawMessage(`{"v":1,"node":"` + node + `","manifest-reads":["a.b"],"stated-at":"` + at + `"}`), nil
+	}
+	f.AskNode("g14", "the first view")
+	if during.From != FromRecord || during.Answered || f.Statements()["g14"].From != FromVerb {
+		t.Errorf("while the kept call asked g14 read %+v; after it %+v", during, f.Statements()["g14"])
+	}
 	if Verb != "manifest-reads" || Event != "manifest-reads-changed" || Consumes != "node-engine.manifest-reads-changed" || Invoke != "seat:node-engine.manifest-reads" {
 		t.Errorf("the names are %s %s %s %s", Verb, Event, Consumes, Invoke)
 	}