From 12126320a5f924708502ae989d00e00aaff0431e Mon Sep 17 00:00:00 2001
From: Jason Quesenberry <beqqrry@amazon.com>
Date: Fri, 17 May 2024 11:46:24 -0700
Subject: [PATCH] Adds filesystem and pause to demotools. Filesystem has a
 test, but pause does not because there is not resultant artifact to test.

---
 gov2/demotools/filesystem.go      | 73 +++++++++++++++++++++++++++++++
 gov2/demotools/filesystem_test.go | 55 +++++++++++++++++++++++
 gov2/demotools/pause.go           | 24 ++++++++++
 3 files changed, 152 insertions(+)
 create mode 100644 gov2/demotools/filesystem.go
 create mode 100644 gov2/demotools/filesystem_test.go
 create mode 100644 gov2/demotools/pause.go

diff --git a/gov2/demotools/filesystem.go b/gov2/demotools/filesystem.go
new file mode 100644
index 00000000000..096fc881203
--- /dev/null
+++ b/gov2/demotools/filesystem.go
@@ -0,0 +1,73 @@
+// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+// Package demotools provides a set of tools that help you write code examples.
+//
+// **FileSystem**
+//
+// The filesystem is used to abstract the os module and allow for
+// variations to be swapped out, such as mocks for testing.
+package demotools
+
+import (
+	"io"
+	"os"
+)
+
+// IFileSystem defines an interface that provides basic file i/o actions.
+type IFileSystem interface {
+	Getwd() (string, error)
+	OpenFile(filename string) (io.ReadWriteCloser, error)
+	CloseFile(file io.ReadWriteCloser)
+}
+
+// FileSystem is a struct to hold the injected object.
+type FileSystem struct{}
+
+// NewStandardFileSystem uses the plain os module implementations.
+func NewStandardFileSystem() *FileSystem {
+	return &FileSystem{}
+}
+
+// Getwd returns the current working directory using the os module.
+func (filesystem FileSystem) Getwd() (string, error) {
+	return os.Getwd()
+}
+
+// OpenFile returns an io.ReadWriterCloser object based on the provided filename.
+func (filesystem FileSystem) OpenFile(filename string) (io.ReadWriteCloser, error) {
+	file, err := os.Open(filename)
+	return file, err
+}
+
+// CloseFile closes the provided file.
+func (filesystem FileSystem) CloseFile(file io.ReadWriteCloser) {
+	defer file.Close()
+}
+
+// MockFileSystem is a mock version of IFileSystem for testing.
+type MockFileSystem struct {
+	mockfile io.ReadWriteCloser
+}
+
+// NewMockFileSystem mocks the FileSystem and holds a singular io.ReadWriteCloser object to return.
+func NewMockFileSystem(mockfile io.ReadWriteCloser) *MockFileSystem {
+	mockfilesystem := MockFileSystem{}
+	mockfilesystem.mockfile = mockfile
+	return &mockfilesystem
+}
+
+// Getwd returns a basic mock directory string.
+func (filesystem MockFileSystem) Getwd() (string, error) {
+	return "mock/dir", nil
+}
+
+// OpenFile returns the io.ReadWriteCloser provided on object creation.
+func (filesystem MockFileSystem) OpenFile(_ string) (io.ReadWriteCloser, error) {
+	return filesystem.mockfile, nil
+}
+
+// CloseFile closes the io.ReadWriteCloser provided on object creation.
+func (filesystem MockFileSystem) CloseFile(_ io.ReadWriteCloser) {
+	defer filesystem.mockfile.Close()
+}
diff --git a/gov2/demotools/filesystem_test.go b/gov2/demotools/filesystem_test.go
new file mode 100644
index 00000000000..078bb1ce8c0
--- /dev/null
+++ b/gov2/demotools/filesystem_test.go
@@ -0,0 +1,55 @@
+// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+package demotools
+
+import (
+	"os"
+	"testing"
+)
+
+func TestNewStandardFileSystemGwd(t *testing.T) {
+	filesystem := NewStandardFileSystem()
+	testGwd, tErr := filesystem.Getwd()
+	realGwd, rErr := os.Getwd()
+	if testGwd != realGwd || tErr != nil || rErr != nil {
+		t.Errorf("NewStandardFileSystemGwd(): got %v, want %v. Errors(%v, %v)", testGwd, realGwd, tErr, rErr)
+	}
+}
+
+func TestNewStandardFileSystemFileIO(t *testing.T) {
+	filesystem := NewStandardFileSystem()
+	filename := "test.txt"
+	os.Create(filename)
+	file, err := filesystem.OpenFile(filename)
+	if err != nil {
+		t.Errorf("NewStandardFileSystemFileInteraction(): error opening file: %v", err)
+	}
+	filesystem.CloseFile(file)
+	err = os.Remove(filename)
+	if err != nil {
+		t.Errorf("NewStandardFileSystemFileInteraction(): error removing file: %v", err)
+	}
+}
+
+func TestNewMockFileSystem(t *testing.T) {
+	filename := "test.txt"
+	file, err := os.Create(filename)
+	if err != nil {
+		t.Errorf("NewMockFileSystem(): error creating file: %v", err)
+	}
+	filesystem := NewMockFileSystem(file)
+	mockGwd, gwdErr := filesystem.Getwd()
+	if mockGwd != "mock/dir" || gwdErr != nil {
+		t.Errorf("NewMockFileSystem(): %v is not correct or the error was: %v", mockGwd, gwdErr)
+	}
+	mockFile, fErr := filesystem.OpenFile("any string will do")
+	if fErr != nil {
+		t.Errorf("NewMockFileSystem(): error opening file: %v", fErr)
+	}
+	filesystem.CloseFile(mockFile)
+	err = os.Remove(filename)
+	if err != nil {
+		t.Errorf("NewMockFileSystem(): error removing file: %v", err)
+	}
+}
diff --git a/gov2/demotools/pause.go b/gov2/demotools/pause.go
new file mode 100644
index 00000000000..2514a57daed
--- /dev/null
+++ b/gov2/demotools/pause.go
@@ -0,0 +1,24 @@
+// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+// Package demotools provides a set of tools that help you write code examples.
+//
+// **Pausable**
+//
+// The pausable interface creates an easy to mock pausing object for testing.
+package demotools
+
+import "time"
+
+// IPausable defines the interface for pausable objects.
+type IPausable interface {
+	Pause(secs int)
+}
+
+// Pauser holds the pausable object.
+type Pauser struct{}
+
+// Pause waits for the specified number of seconds.
+func (pausable Pauser) Pause(secs int) {
+	time.Sleep(time.Duration(secs) * time.Second)
+}