test(e2e): add helper function for finding worker by filter

- Add `GetWorkerWithFilterCLI` helper function for finding a worker by Address

testing/internal/e2e/boundary/worker.go

@@ -0,0 +1,46 @@
+// Copyright (c) HashiCorp, Inc.
+// SPDX-License-Identifier: BUSL-1.1
+
+package boundary
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"testing"
+
+	"github.com/hashicorp/boundary/api/workers"
+	"github.com/hashicorp/boundary/testing/internal/e2e"
+)
+
+// GetWorkerWithFilterCli returns a worker using the boundary CLI with a filter
+// If no worker is found, an error is returned.
+// If more than 1 worker is found, an error is returned.
+func GetWorkerWithFilterCli(t testing.TB, ctx context.Context, filter string) (*workers.Worker, error) {
+	output := e2e.RunCommand(ctx, "boundary",
+		e2e.WithArgs(
+			"workers", "list",
+			"-format", "json",
+			"-filter", filter,
+		),
+	)
+	if output.Err != nil {
+		return nil, fmt.Errorf("%w: %s", output.Err, string(output.Stderr))
+	}
+
+	var workersListResult workers.WorkerListResult
+	err := json.Unmarshal(output.Stdout, &workersListResult)
+	if err != nil {
+		return nil, fmt.Errorf("failed to unmarshal workers list result: %w", err)
+	}
+
+	items := workersListResult.GetItems()
+	if len(items) == 0 {
+		return nil, fmt.Errorf("no workers found using filter: %s", filter)
+	}
+	if len(items) > 1 {
+		return nil, fmt.Errorf("more than 1 worker found. Found %v workers using filter: %s", len(items), filter)
+	}
+
+	return items[0], nil
+}