Backport of test(e2e): Add test for idle pending tcp connect session into release/0.21.x (#6555)

* backport of commit 3c8b3065b0

* backport of commit fb8916cb37

* move test to base; include port fix changes

---------

Co-authored-by: Tony <wongtonyb@gmail.com>

testing/internal/e2e/tests/base/target_tcp_connect_pending_test.go

@@ -0,0 +1,94 @@
+// Copyright IBM Corp. 2020, 2025
+// SPDX-License-Identifier: BUSL-1.1
+
+package base_test
+
+import (
+	"context"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/hashicorp/boundary/internal/session"
+	"github.com/hashicorp/boundary/internal/target"
+	"github.com/hashicorp/boundary/testing/internal/e2e"
+	"github.com/hashicorp/boundary/testing/internal/e2e/boundary"
+	"github.com/stretchr/testify/require"
+)
+
+// TestCliTcpTargetConnectPending uses the boundary cli to connect
+// to a target using `boundary connect`, waits for 10 seconds to ensure the session is still active, and then uses ssh to connect through the session
+func TestCliTcpTargetConnectPending(t *testing.T) {
+	e2e.MaybeSkipTest(t)
+	c, err := loadTestConfig()
+	require.NoError(t, err)
+
+	ctx := t.Context()
+	boundary.AuthenticateAdminCli(t, ctx)
+	orgId, err := boundary.CreateOrgCli(t, ctx)
+	require.NoError(t, err)
+	t.Cleanup(func() {
+		ctx := context.Background()
+		boundary.AuthenticateAdminCli(t, ctx)
+		output := e2e.RunCommand(ctx, "boundary", e2e.WithArgs("scopes", "delete", "-id", orgId))
+		require.NoError(t, output.Err, string(output.Stderr))
+	})
+	projectId, err := boundary.CreateProjectCli(t, ctx, orgId)
+	require.NoError(t, err)
+	targetId, err := boundary.CreateTargetCli(t, ctx, projectId, c.TargetPort, []target.Option{target.WithAddress(c.TargetAddress)})
+	require.NoError(t, err)
+
+	// Start a session
+	ctxCancel, cancel := context.WithCancel(context.Background())
+	port := "12345"
+	cmdChan := make(chan *e2e.CommandResult)
+	go func() {
+		t.Log("Starting session...")
+		cmdChan <- e2e.RunCommand(ctxCancel, "boundary",
+			e2e.WithArgs(
+				"connect",
+				"-target-id", targetId,
+				"-listen-port", port,
+				"-format", "json",
+			),
+		)
+	}()
+	t.Cleanup(cancel)
+
+	s := boundary.WaitForSessionCli(t, ctx, projectId, nil)
+	boundary.WaitForSessionStatusCli(t, ctx, s.Id, session.StatusPending.String())
+
+	t.Log("Waiting 10 seconds to ensure session is still active...")
+	time.Sleep(10 * time.Second)
+
+	select {
+	case output := <-cmdChan:
+		t.Fatalf("boundary connect exited early: stdout=%s stderr=%s", output.Stdout, output.Stderr)
+	default:
+	}
+	boundary.WaitForSessionStatusCli(t, ctx, s.Id, session.StatusPending.String())
+
+	output := e2e.RunCommand(ctx, "ssh",
+		e2e.WithArgs(
+			"localhost",
+			"-p", port,
+			"-l", c.TargetSshUser,
+			"-i", c.TargetSshKeyPath,
+			"-o", "UserKnownHostsFile=/dev/null",
+			"-o", "StrictHostKeyChecking=no",
+			"-o", "IdentitiesOnly=yes",
+			"hostname -i",
+		),
+	)
+	require.NoError(t, output.Err, string(output.Stderr))
+	require.Equal(t, c.TargetAddress, strings.TrimSpace(string(output.Stdout)))
+	require.Equal(t, 0, output.ExitCode)
+
+	cancel()
+
+	select {
+	case <-cmdChan:
+	case <-time.After(5 * time.Second):
+		t.Fatal("Timed out waiting for session command to exit")
+	}
+}