tests: fix container leak and improve SSH server reliability

Add container cleanup via t.Cleanup to prevent resource leaks, add signal
trapping in the SSH server script for clean shutdown, use the container IP
instead of 127.0.0.1 for readiness checks, and propagate context errors
through CloseWithError for better timeout diagnostics.

Signed-off-by: Brian Goff <cpuguy83@gmail.com>

Author: cpuguy83

test/git_services/teststate.go

@@ -4,7 +4,6 @@ import (
 	"bufio"
 	"bytes"
 	"context"
-	_ "embed"
 	"encoding/json"
 	"errors"
 	"fmt"
@@ -178,6 +177,10 @@ func (ts *TestState) newContainer(ctx context.Context, rootfs llb.State) gwclien
 		t.Fatalf("could not create container: %s", err)
 	}
 
+	t.Cleanup(func() {
+		cont.Release(context.WithoutCancel(ctx)) //nolint:errcheck
+	})
+
 	return cont
 }
 
@@ -224,6 +227,10 @@ func (ts *TestState) StartSSHServer(ctx context.Context, gitHost llb.State) Serv
             #!/usr/bin/env sh
             set -e
 
+            # Make sure we trap exit signals
+            # This is POSIX shell, not bash, so we can't use the "EXIT" shorthand
+            trap exit INT HUP TERM
+
             IP=$({{ .HTTPServerPath }} getip)
             PORT="{{ .SSHPort }}"
 
@@ -235,7 +242,7 @@ func (ts *TestState) StartSSHServer(ctx context.Context, gitHost llb.State) Serv
             SERVER_PID=$!
 
             # Wait for server to be ready
-            while ! nc -zw5 127.0.0.1 "$PORT" 2>/dev/null; do
+            while ! nc -zw5 "${IP}" "$PORT" 2>/dev/null; do
                 # Check if server is still running
                 if ! kill -0 $SERVER_PID 2>/dev/null; then
                     echo '{"type":"error","error":{"message":"sshd exited unexpectedly"}}'
@@ -367,16 +374,14 @@ func (ts *TestState) waitForReady(ctx context.Context, proc *containerProcess, t
 	// Close the pipe on timeout to unblock the decoder
 	go func() {
 		<-ctx.Done()
-		proc.stdoutR.Close()
+		proc.stdoutR.CloseWithError(ctx.Err())
 	}()
 
 	for event, err := range proc.Events() {
 		if err != nil {
-			if ctx.Err() != nil {
-				t.Fatalf("timeout waiting for server ready event")
-			}
 			t.Fatalf("error reading event: %v", err)
 		}
+
 		switch event.Type {
 		case EventTypeReady:
 			if event.Ready == nil {