Delete a forwarded opening the way ufw accepts it, and read a fresh machine's resolver as not in use — both measured on a lab machine (hq ADR 0100)

internal/bootstrap/inuse_test.go

@@ -2,6 +2,7 @@ package bootstrap
 
 import (
 	"context"
+	"os"
 	"path/filepath"
 	"strings"
 	"testing"
@@ -13,8 +14,8 @@ import (
 // and listener it counted.
 
 // Lines as `ss -Hltunp` prints them. The ssh, samba, loopback and proxy lines are captured from a
-// real machine; the resolver, DHCP and time lines are written in the same shape for the processes a
-// fresh machine runs, and still need measuring against one.
+// real machine; the resolver, DHCP and time lines are written in the same shape. What a fresh machine
+// actually runs is measured in testdata/fresh-machine-listeners.txt.
 const inUseSockets = `tcp LISTEN 0      128                                        0.0.0.0:22    0.0.0.0:* users:(("sshd",pid=1188536,fd=6))
 tcp LISTEN 0      128                                           [::]:22       [::]:* users:(("sshd",pid=1188536,fd=7))
 tcp LISTEN 0      32                                       127.0.0.1:53    0.0.0.0:* users:(("dnsmasq",pid=1189392,fd=7))
@@ -97,3 +98,25 @@ func TestARerunOfGenesisIsNotAMachineInUse(t *testing.T) {
 		t.Errorf("what an earlier genesis raised was counted as a machine in use: %v", err)
 	}
 }
+
+func TestAFreshlyInstalledMachineAsMeasuredIsNotInUse(t *testing.T) {
+	// Captured with `ss -Hltunp` on a freshly installed lab machine: its resolver listens on TCP on
+	// every address, which the record's words alone would count.
+	raw, err := os.ReadFile("testdata/fresh-machine-listeners.txt")
+	if err != nil {
+		t.Fatal(err)
+	}
+	run := func(ctx context.Context, name string, args ...string) (string, error) {
+		if name == "ss" {
+			return string(raw), nil
+		}
+		return "", nil
+	}
+	containers, listeners, err := InUse(context.Background(), run, func(string) bool { return false })
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(containers) != 0 || len(listeners) != 0 {
+		t.Errorf("a fresh machine read as in use: containers %v, listeners %v", containers, listeners)
+	}
+}