Add test tooling for signals

Signed-off-by: apostasie <spam_blackhole@farcloser.world>

Author: apostasie

pkg/testutil/nerdtest/utilities_linux.go

@@ -0,0 +1,69 @@
+/*
+   Copyright The containerd Authors.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
+package nerdtest
+
+import (
+	"os"
+	"strconv"
+	"strings"
+	"syscall"
+	"time"
+
+	"github.com/containerd/nerdctl/v2/pkg/testutil"
+	"github.com/containerd/nerdctl/v2/pkg/testutil/test"
+)
+
+const SignalCaught = "received"
+
+var SigQuit os.Signal = syscall.SIGQUIT
+var SigUsr1 os.Signal = syscall.SIGUSR1
+
+func RunSigProxyContainer(signal os.Signal, exitOnSignal bool, args []string, data test.Data, helpers test.Helpers) test.TestableCommand {
+	sig := strconv.Itoa(int(signal.(syscall.Signal)))
+	ready := "trap ready"
+	script := `#!/bin/sh
+	set -eu
+
+	sig_msg () {
+		printf "` + SignalCaught + `\n"
+		[ "` + strconv.FormatBool(exitOnSignal) + `" != true ] || exit 0
+	}
+
+	trap sig_msg ` + sig + `
+	printf "` + ready + `\n"
+	while true; do
+		sleep 0.1
+	done
+`
+
+	args = append(args, "--name", data.Identifier(), testutil.CommonImage, "sh", "-c", script)
+	args = append([]string{"run"}, args...)
+
+	cmd := helpers.Command(args...)
+	cmd.Background(10 * time.Second)
+	EnsureContainerStarted(helpers, data.Identifier())
+
+	for {
+		out := helpers.Capture("logs", data.Identifier())
+		if strings.Contains(out, ready) {
+			break
+		}
+		time.Sleep(100 * time.Millisecond)
+	}
+
+	return cmd
+}

pkg/testutil/test/command.go

@@ -185,6 +185,10 @@ func (gc *GenericCommand) Background(timeout time.Duration) {
 	gc.result = icmd.StartCmd(i)
 }
 
+func (gc *GenericCommand) Signal(sig os.Signal) error {
+	return gc.result.Cmd.Process.Signal(sig)
+}
+
 func (gc *GenericCommand) withEnv(env map[string]string) {
 	if gc.Env == nil {
 		gc.Env = map[string]string{}

pkg/testutil/test/test.go

@@ -114,6 +114,8 @@ type TestableCommand interface {
 	Run(expect *Expected)
 	// Background allows starting a command in the background
 	Background(timeout time.Duration)
+	// Signal sends a signal to a backgrounded command
+	Signal(sig os.Signal) error
 	// Stderr allows retrieving the raw stderr output of the command
 	Stderr() string
 }

pkg/testutil/testutil_linux.go

@@ -54,25 +54,6 @@ var (
 	// It should be "connection refused" as per the TCP RFC.
 	// https://www.rfc-editor.org/rfc/rfc793
 	ExpectedConnectionRefusedError = "connection refused"
-
-	SigProxyTrueOut    = "received SIGINT"
-	SigProxyTimeoutMsg = "Timed Out; No signal received"
-	SigProxyTestScript = `#!/bin/sh
-	set -eu
-
-	sig_msg () {
-		printf "` + SigProxyTrueOut + `"
-		end
-	}
-
-	trap sig_msg INT
-	timeout=0
-	while [ $timeout -ne 10 ]; do
-		timeout=$((timeout+1))
-		sleep 1
-	done
-	printf "` + SigProxyTimeoutMsg + `"
-	end`
 )
 
 const (