Add doc.go with package documentation for godoc

Author: umputun

doc.go

@@ -0,0 +1,37 @@
+// Package testutils provides a collection of utilities for testing Go applications, including stdout/stderr capture,
+// file handling, HTTP test helpers, and test containers.
+//
+// It consists of several main components:
+//
+// Capture Utilities:
+//   - CaptureStdout, CaptureStderr, CaptureStdoutAndStderr: Functions to capture output from standard streams
+//     during test execution. These are useful for testing functions that write directly to stdout/stderr.
+//     Note: These functions are not thread-safe for parallel tests.
+//
+// File Utilities:
+//   - WriteTestFile: Creates a temporary file with specified content for testing purposes,
+//     with automatic cleanup after the test completes.
+//
+// HTTP Utilities:
+//   - MockHTTPServer: Creates a test HTTP server with the provided handler
+//   - HTTPRequestCaptor: Captures and records HTTP requests for later inspection
+//
+// Test Containers:
+// The 'containers' subpackage provides Docker containers for integration testing:
+//   - SSHTestContainer: SSH server container with file operation support (upload, download, list, delete)
+//   - FTPTestContainer: FTP server container with file operation support
+//   - PostgresTestContainer: PostgreSQL database container with automatic DB creation
+//   - MySQLTestContainer: MySQL database container with automatic DB creation
+//   - MongoTestContainer: MongoDB container with support for multiple versions
+//   - LocalstackTestContainer: LocalStack container with S3 service for AWS testing
+//
+// All container implementations support a common pattern:
+//   - Container creation with NewXXXTestContainer
+//   - Automatic port mapping and connection configuration
+//   - Graceful shutdown with the Close method
+//   - File operations where applicable (SaveFile, GetFile, ListFiles, DeleteFile)
+//
+// These utilities help simplify test setup, improve test reliability, and reduce
+// boilerplate code in test suites, especially for integration tests.
+
+package testutils