test(11-07): pin that a keyless Typesense engine is never configured

- TestSyncEngineRegistration: the typesense import registers the driver
  and a missing or blank api_key reports Configured false, the gate that
  keeps beachcomber from sending anything

modules/beachcomber/typesense/engine_test.go

@@ -338,3 +338,32 @@ func TestEngineConfig(t *testing.T) {
 		t.Fatal("unwrapURLError changed a plain error")
 	}
 }
+
+// TestSyncEngineRegistration covers the engine side of the sync gates
+// (T-11-25): importing the package registers "typesense" for
+// search.driver, and without search.typesense.api_key the engine reports
+// itself unconfigured, which is what makes beachcomber skip every sync
+// before any request.
+func TestSyncEngineRegistration(t *testing.T) {
+	cfg, err := compass.Open(compass.Options{Dir: t.TempDir(), Env: "testing", Environ: []string{}})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if err := cfg.Set("search.driver", "typesense"); err != nil {
+		t.Fatal(err)
+	}
+	svc, err := beachcomber.From(backpack.New(cfg))
+	if err != nil {
+		t.Fatal(err)
+	}
+	e, ok := svc.Engine().(*Engine)
+	if !ok || e.Configured() {
+		t.Fatalf("engine without an API key = %#v, want an unconfigured *typesense.Engine", svc.Engine())
+	}
+	if err := cfg.Set("search.typesense.api_key", "   "); err != nil {
+		t.Fatal(err)
+	}
+	if LoadConfig(cfg).APIKey != "" || New(LoadConfig(cfg)).Configured() {
+		t.Fatal("a blank API key counts as configured")
+	}
+}