diff --git a/system/Files/Exceptions/FileException.php b/system/Files/Exceptions/FileException.php
index ddaac3639b72..ffcfb61c0bbc 100644
--- a/system/Files/Exceptions/FileException.php
+++ b/system/Files/Exceptions/FileException.php
@@ -23,4 +23,24 @@ public static function forUnableToMove(string $from = null, string $to = null, s
     {
         return new static(lang('Files.cannotMove', [$from, $to, $error]));
     }
+
+	/**
+	 * Throws when an item is expected to be a directory but is not or is missing.
+	 *
+	 * @param string $caller The method causing the exception
+	 */
+	public static function forExpectedDirectory(string $caller)
+	{
+		return new static(lang('Files.expectedDirectory', [$caller]));
+	}
+
+	/**
+	 * Throws when an item is expected to be a file but is not or is missing.
+	 *
+	 * @param string $caller The method causing the exception
+	 */
+	public static function forExpectedFile(string $caller)
+	{
+		return new static(lang('Files.expectedFile', [$caller]));
+	}
 }
diff --git a/system/Files/FileCollection.php b/system/Files/FileCollection.php
new file mode 100644
index 000000000000..128d884940d5
--- /dev/null
+++ b/system/Files/FileCollection.php
@@ -0,0 +1,405 @@
+<?php
+
+/**
+ * This file is part of the CodeIgniter 4 framework.
+ *
+ * (c) CodeIgniter Foundation <admin@codeigniter.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace CodeIgniter\Files;
+
+use CodeIgniter\Files\Exceptions\FileException;
+use CodeIgniter\Files\Exceptions\FileNotFoundException;
+use Countable;
+use Generator;
+use InvalidArgumentException;
+use IteratorAggregate;
+use Traversable;
+
+/**
+ * File Collection Class
+ *
+ * Representation for a group of files, with utilities for locating,
+ * filtering, and ordering them.
+ */
+class FileCollection implements Countable, IteratorAggregate
+{
+	/**
+	 * The current list of file paths.
+	 *
+	 * @var string[]
+	 */
+	protected $files = [];
+
+	//--------------------------------------------------------------------
+	// Support Methods
+	//--------------------------------------------------------------------
+
+	/**
+	 * Resolves a full path and verifies it is an actual directory.
+	 *
+	 * @param string $directory
+	 *
+	 * @return string
+	 *
+	 * @throws FileException
+	 */
+	final protected static function resolveDirectory(string $directory): string
+	{
+		if (! is_dir($directory = set_realpath($directory)))
+		{
+			$caller = debug_backtrace(DEBUG_BACKTRACE_IGNORE_ARGS, 2)[1];
+			throw FileException::forExpectedDirectory($caller['function']);
+		}
+
+		return $directory;
+	}
+
+	/**
+	 * Resolves a full path and verifies it is an actual file.
+	 *
+	 * @param string $file
+	 *
+	 * @return string
+	 *
+	 * @throws FileException
+	 */
+	final protected static function resolveFile(string $file): string
+	{
+		if (! is_file($file = set_realpath($file)))
+		{
+			$caller = debug_backtrace(DEBUG_BACKTRACE_IGNORE_ARGS, 2)[1];
+			throw FileException::forExpectedFile($caller['function']);
+		}
+
+		return $file;
+	}
+
+	/**
+	 * Removes files that are not part of the given directory (recursive).
+	 *
+	 * @param string[] $files
+	 * @param string   $directory
+	 *
+	 * @return string[]
+	 */
+	final protected static function filterFiles(array $files, string $directory): array
+	{
+		$directory = self::resolveDirectory($directory);
+
+		return array_filter($files, static function (string $value) use ($directory): bool {
+			return strpos($value, $directory) === 0;
+		});
+	}
+
+	/**
+	 * Returns any files whose `basename` matches the given pattern.
+	 *
+	 * @param string[] $files
+	 * @param string   $pattern Regex or pseudo-regex string
+	 *
+	 * @return string[]
+	 */
+	final protected static function matchFiles(array $files, string $pattern): array
+	{
+		// Convert pseudo-regex into their true form
+		if (@preg_match($pattern, '') === false)
+		{
+			$pattern = str_replace(
+				['#', '.', '*', '?'],
+				['\#', '\.', '.*', '.'],
+				$pattern
+			);
+			$pattern = "#{$pattern}#";
+		}
+
+		return array_filter($files, static function ($value) use ($pattern) {
+			return (bool) preg_match($pattern, basename($value));
+		});
+	}
+
+	//--------------------------------------------------------------------
+	// Class Core
+	//--------------------------------------------------------------------
+
+	/**
+	 * Loads the Filesystem helper and adds any initial files.
+	 *
+	 * @param string[] $files
+	 */
+	public function __construct(array $files = [])
+	{
+		helper(['filesystem']);
+
+		$this->add($files)->define();
+	}
+
+	/**
+	 * Applies any initial inputs after the constructor.
+	 * This method is a stub to be implemented by child classes.
+	 *
+	 * @return void
+	 */
+	protected function define(): void
+	{
+	}
+
+	/**
+	 * Optimizes and returns the current file list.
+	 *
+	 * @return string[]
+	 */
+	public function get(): array
+	{
+		$this->files = array_unique($this->files);
+		sort($this->files, SORT_STRING);
+
+		return $this->files;
+	}
+
+	/**
+	 * Sets the file list directly, files are still subject to verification.
+	 * This works as a "reset" method with [].
+	 *
+	 * @param string[] $files The new file list to use
+	 *
+	 * @return $this
+	 */
+	public function set(array $files)
+	{
+		$this->files = [];
+
+		return $this->addFiles($files);
+	}
+
+	/**
+	 * Adds an array/single file or directory to the list.
+	 *
+	 * @param string|string[] $paths
+	 * @param boolean         $recursive
+	 *
+	 * @return $this
+	 */
+	public function add($paths, bool $recursive = true)
+	{
+		$paths = (array) $paths;
+
+		foreach ($paths as $path)
+		{
+			if (! is_string($path))
+			{
+				throw new InvalidArgumentException('FileCollection paths must be strings.');
+			}
+
+			// Test for a directory
+			try
+			{
+				$directory = self::resolveDirectory($path);
+			}
+			catch (FileException $e)
+			{
+				return $this->addFile($path);
+			}
+
+			$this->addDirectory($path, $recursive);
+		}
+
+		return $this;
+	}
+
+	//--------------------------------------------------------------------
+	// File Handling
+	//--------------------------------------------------------------------
+
+	/**
+	 * Verifies and adds files to the list.
+	 *
+	 * @param string[] $files
+	 *
+	 * @return $this
+	 */
+	public function addFiles(array $files)
+	{
+		foreach ($files as $file)
+		{
+			$this->addFile($file);
+		}
+
+		return $this;
+	}
+
+	/**
+	 * Verifies and adds a single file to the file list.
+	 *
+	 * @param string $file
+	 *
+	 * @return $this
+	 */
+	public function addFile(string $file)
+	{
+		$this->files[] = self::resolveFile($file);
+
+		return $this;
+	}
+
+	/**
+	 * Removes files from the list.
+	 *
+	 * @param string[] $files
+	 *
+	 * @return $this
+	 */
+	public function removeFiles(array $files)
+	{
+		$this->files = array_diff($this->files, $files);
+
+		return $this;
+	}
+
+	/**
+	 * Removes a single file from the list.
+	 *
+	 * @param string $file
+	 *
+	 * @return $this
+	 */
+	public function removeFile(string $file)
+	{
+		return $this->removeFiles([$file]);
+	}
+
+	//--------------------------------------------------------------------
+	// Directory Handling
+	//--------------------------------------------------------------------
+
+	/**
+	 * Verifies and adds files from each
+	 * directory to the list.
+	 *
+	 * @param string[] $directories
+	 * @param bool $recursive
+	 *
+	 * @return $this
+	 */
+	public function addDirectories(array $directories, bool $recursive = false)
+	{
+		foreach ($directories as $directory)
+		{
+			$this->addDirectory($directory, $recursive);
+		}
+
+		return $this;
+	}
+
+	/**
+	 * Verifies and adds all files from a directory.
+	 *
+	 * @param string  $directory
+	 * @param boolean $recursive
+	 *
+	 * @return $this
+	 */
+	public function addDirectory(string $directory, bool $recursive = false)
+	{
+		$directory = self::resolveDirectory($directory);
+
+		// Map the directory to depth 2 to so directories become arrays
+		foreach (directory_map($directory, 2, true) as $key => $path)
+		{
+			if (is_string($path))
+			{
+				$this->addFile($directory . $path);
+			}
+			elseif ($recursive && is_array($path))
+			{
+				$this->addDirectory($directory . $key, true);
+			}
+		}
+
+		return $this;
+	}
+
+	//--------------------------------------------------------------------
+	// Filtering
+	//--------------------------------------------------------------------
+
+	/**
+	 * Removes any files from the list that match the supplied pattern
+	 * (within the optional scope).
+	 *
+	 * @param string      $pattern Regex or pseudo-regex string
+	 * @param string|null $scope The directory to limit the scope
+	 *
+	 * @return $this
+	 */
+	public function removePattern(string $pattern, string $scope = null)
+	{
+		if ($pattern === '')
+		{
+			return $this;
+		}
+
+		// Start with all files or those in scope
+		$files = is_null($scope) ? $this->files : self::filterFiles($this->files, $scope);
+
+		// Remove any files that match the pattern
+		return $this->removeFiles(self::matchFiles($files, $pattern));
+	}
+
+	/**
+	 * Keeps only the files from the list that match
+	 * (within the optional scope).
+	 *
+	 * @param string      $pattern Regex or pseudo-regex string
+	 * @param string|null $scope A directory to limit the scope
+	 *
+	 * @return $this
+	 */
+	public function retainPattern(string $pattern, string $scope = null)
+	{
+		if ($pattern === '')
+		{
+			return $this;
+		}
+
+		// Start with all files or those in scope
+		$files = is_null($scope) ? $this->files : self::filterFiles($this->files, $scope);
+
+		// Matches the pattern within the scoped files and remove their inverse.
+		return $this->removeFiles(array_diff($files, self::matchFiles($files, $pattern)));
+	}
+
+	//--------------------------------------------------------------------
+	// Interface Methods
+	//--------------------------------------------------------------------
+
+    /**
+     * Returns the current number of files in the collection.
+     * Fulfills Countable.
+     *
+     * @return int
+     */
+    public function count(): int
+    {
+        return count($this->files);
+    }
+
+    /**
+     * Yields as an Iterator for the current files.
+     * Fulfills IteratorAggregate.
+     *
+     * @throws FileNotFoundException
+     *
+     * @return Generator<File>
+     */
+    public function getIterator(): Generator
+    {
+    	foreach ($this->get() as $file)
+    	{
+    		yield new File($file, true);
+    	}
+    }
+}
diff --git a/system/Language/en/Files.php b/system/Language/en/Files.php
index ccb9ab306876..f50764898fe3 100644
--- a/system/Language/en/Files.php
+++ b/system/Language/en/Files.php
@@ -11,6 +11,8 @@
 
 // Files language settings
 return [
-    'fileNotFound' => 'File not found: {0}',
-    'cannotMove'   => 'Could not move file {0} to {1} ({2}).',
+    'fileNotFound'      => 'File not found: {0}',
+    'cannotMove'        => 'Could not move file {0} to {1} ({2}).',
+	'expectedDirectory' => '{0} expects a valid directory.',
+	'expectedFile'      => '{0} expects a valid file.',
 ];
diff --git a/system/Language/en/Publisher.php b/system/Language/en/Publisher.php
index 2d7ae8418b25..77d805a78ff2 100644
--- a/system/Language/en/Publisher.php
+++ b/system/Language/en/Publisher.php
@@ -12,8 +12,6 @@
 // Publisher language settings
 return [
 	'collision'             => 'Publisher encountered an unexpected {0} while copying {1} to {2}.',
-	'expectedDirectory'     => 'Publisher::{0} expects a valid directory.',
-	'expectedFile'          => 'Publisher::{0} expects a valid file.',
 	'destinationNotAllowed' => 'Destination is not on the allowed list of Publisher directories: {0}',
 	'fileNotAllowed'        => '{0} fails the following restriction for {1}: {2}',
 
diff --git a/system/Publisher/Exceptions/PublisherException.php b/system/Publisher/Exceptions/PublisherException.php
index d54420881ec7..c3e85a994ebe 100644
--- a/system/Publisher/Exceptions/PublisherException.php
+++ b/system/Publisher/Exceptions/PublisherException.php
@@ -31,26 +31,6 @@ public static function forCollision(string $from, string $to)
 		return new static(lang('Publisher.collision', [filetype($to), $from, $to]));
 	}
 
-	/**
-	 * Throws when an object is expected to be a directory but is not or is missing.
-	 *
-	 * @param string $caller The method causing the exception
-	 */
-	public static function forExpectedDirectory(string $caller)
-	{
-		return new static(lang('Publisher.expectedDirectory', [$caller]));
-	}
-
-	/**
-	 * Throws when an object is expected to be a file but is not or is missing.
-	 *
-	 * @param string $caller The method causing the exception
-	 */
-	public static function forExpectedFile(string $caller)
-	{
-		return new static(lang('Publisher.expectedFile', [$caller]));
-	}
-
 	/**
 	 * Throws when given a destination that is not in the list of allowed directories.
 	 *
diff --git a/system/Publisher/Publisher.php b/system/Publisher/Publisher.php
index 1bfd4b91768d..ab4484cdea0b 100644
--- a/system/Publisher/Publisher.php
+++ b/system/Publisher/Publisher.php
@@ -12,7 +12,7 @@
 namespace CodeIgniter\Publisher;
 
 use CodeIgniter\Autoloader\FileLocator;
-use CodeIgniter\Files\File;
+use CodeIgniter\Files\FileCollection;
 use CodeIgniter\HTTP\URI;
 use CodeIgniter\Publisher\Exceptions\PublisherException;
 use RuntimeException;
@@ -28,13 +28,13 @@
  * path to a verified file while a "path" is relative to its source
  * or destination and may indicate either a file or directory of
  * unconfirmed existence.
- * class failures throw the PublisherException, but some underlying
+ * Class failures throw the PublisherException, but some underlying
  * methods may percolate different exceptions, like FileException,
  * FileNotFoundException or InvalidArgumentException.
  * Write operations will catch all errors in the file-specific
  * $errors property to minimize impact of partial batch operations.
  */
-class Publisher
+class Publisher extends FileCollection
 {
 	/**
 	 * Array of discovered Publishers.
@@ -51,13 +51,6 @@ class Publisher
 	 */
 	private $scratch;
 
-	/**
-	 * The current list of files.
-	 *
-	 * @var string[]
-	 */
-	private $files = [];
-
 	/**
 	 * Exceptions for specific files from the last write operation.
 	 *
@@ -94,6 +87,10 @@ class Publisher
 	 */
 	protected $destination = FCPATH;
 
+	//--------------------------------------------------------------------
+	// Support Methods
+	//--------------------------------------------------------------------
+
 	/**
 	 * Discovers and returns all Publishers in the specified namespace directory.
 	 *
@@ -134,95 +131,6 @@ final public static function discover(string $directory = 'Publishers'): array
 		return self::$discovered[$directory];
 	}
 
-	//--------------------------------------------------------------------
-
-	/**
-	 * Resolves a full path and verifies it is an actual directory.
-	 *
-	 * @param string $directory
-	 *
-	 * @return string
-	 *
-	 * @throws PublisherException
-	 */
-	private static function resolveDirectory(string $directory): string
-	{
-		if (! is_dir($directory = set_realpath($directory)))
-		{
-			$caller = debug_backtrace(DEBUG_BACKTRACE_IGNORE_ARGS, 2)[1];
-			throw PublisherException::forExpectedDirectory($caller['function']);
-		}
-
-		return $directory;
-	}
-
-	/**
-	 * Resolves a full path and verifies it is an actual file.
-	 *
-	 * @param string $file
-	 *
-	 * @return string
-	 *
-	 * @throws PublisherException
-	 */
-	private static function resolveFile(string $file): string
-	{
-		if (! is_file($file = set_realpath($file)))
-		{
-			$caller = debug_backtrace(DEBUG_BACKTRACE_IGNORE_ARGS, 2)[1];
-			throw PublisherException::forExpectedFile($caller['function']);
-		}
-
-		return $file;
-	}
-
-	//--------------------------------------------------------------------
-
-	/**
-	 * Removes files that are not part of the given directory (recursive).
-	 *
-	 * @param string[] $files
-	 * @param string   $directory
-	 *
-	 * @return string[]
-	 */
-	private static function filterFiles(array $files, string $directory): array
-	{
-		$directory = self::resolveDirectory($directory);
-
-		return array_filter($files, function ($value) use ($directory) {
-			return strpos($value, $directory) === 0;
-		});
-	}
-
-	/**
-	 * Returns any files whose `basename` matches the given pattern.
-	 *
-	 * @param array<string> $files
-	 * @param string        $pattern Regex or pseudo-regex string
-	 *
-	 * @return string[]
-	 */
-	private static function matchFiles(array $files, string $pattern): array
-	{
-		// Convert pseudo-regex into their true form
-		if (@preg_match($pattern, null) === false) // @phpstan-ignore-line
-		{
-			$pattern = str_replace(
-				['#', '.', '*', '?'],
-				['\#', '\.', '.*', '.'],
-				$pattern
-			);
-			$pattern = "#{$pattern}#";
-		}
-
-		return array_filter($files, function ($value) use ($pattern) {
-			return (bool) preg_match($pattern, basename($value));
-		});
-	}
-
-	//--------------------------------------------------------------------
-
 	/*
 	 * Removes a directory and all its files and subdirectories.
 	 *
@@ -248,6 +156,8 @@ private static function wipeDirectory(string $directory): void
 		}
 	}
 
+	//--------------------------------------------------------------------
+	// Class Core
 	//--------------------------------------------------------------------
 
 	/**
@@ -305,12 +215,14 @@ public function publish(): bool
 		// Safeguard against accidental misuse
 		if ($this->source === ROOTPATH && $this->destination === FCPATH)
 		{
-			throw new RuntimeException('Child classes of Publisher should provide their own source and destination or publish method.');
+			throw new RuntimeException('Child classes of Publisher should provide their own publish method or a source and destination.');
 		}
 
 		return $this->addPath('/')->merge(true);
 	}
 
+	//--------------------------------------------------------------------
+	// Property Accessors
 	//--------------------------------------------------------------------
 
 	/**
@@ -369,142 +281,8 @@ final public function getPublished(): array
 		return $this->published;
 	}
 
-	/**
-	 * Optimizes and returns the current file list.
-	 *
-	 * @return string[]
-	 */
-	final public function getFiles(): array
-	{
-		$this->files = array_unique($this->files, SORT_STRING);
-		sort($this->files, SORT_STRING);
-
-		return $this->files;
-	}
-
 	//--------------------------------------------------------------------
-
-	/**
-	 * Sets the file list directly, files are still subject to verification.
-	 * This works as a "reset" method with [].
-	 *
-	 * @param string[] $files The new file list to use
-	 *
-	 * @return $this
-	 */
-	final public function setFiles(array $files)
-	{
-		$this->files = [];
-
-		return $this->addFiles($files);
-	}
-
-	/**
-	 * Verifies and adds files to the list.
-	 *
-	 * @param string[] $files
-	 *
-	 * @return $this
-	 */
-	final public function addFiles(array $files)
-	{
-		foreach ($files as $file)
-		{
-			$this->addFile($file);
-		}
-
-		return $this;
-	}
-
-	/**
-	 * Verifies and adds a single file to the file list.
-	 *
-	 * @param string $file
-	 *
-	 * @return $this
-	 */
-	final public function addFile(string $file)
-	{
-		$this->files[] = self::resolveFile($file);
-
-		return $this;
-	}
-
-	/**
-	 * Removes files from the list.
-	 *
-	 * @param string[] $files
-	 *
-	 * @return $this
-	 */
-	final public function removeFiles(array $files)
-	{
-		$this->files = array_diff($this->files, $files);
-
-		return $this;
-	}
-
-	/**
-	 * Removes a single file from the list.
-	 *
-	 * @param string $file
-	 *
-	 * @return $this
-	 */
-	final public function removeFile(string $file)
-	{
-		return $this->removeFiles([$file]);
-	}
-
-	//--------------------------------------------------------------------
-
-	/**
-	 * Verifies and adds files from each
-	 * directory to the list.
-	 *
-	 * @param string[] $directories
-	 * @param bool $recursive
-	 *
-	 * @return $this
-	 */
-	final public function addDirectories(array $directories, bool $recursive = false)
-	{
-		foreach ($directories as $directory)
-		{
-			$this->addDirectory($directory, $recursive);
-		}
-
-		return $this;
-	}
-
-	/**
-	 * Verifies and adds all files from a directory.
-	 *
-	 * @param string  $directory
-	 * @param boolean $recursive
-	 *
-	 * @return $this
-	 */
-	final public function addDirectory(string $directory, bool $recursive = false)
-	{
-		$directory = self::resolveDirectory($directory);
-
-		// Map the directory to depth 2 to so directories become arrays
-		foreach (directory_map($directory, 2, true) as $key => $path)
-		{
-			if (is_string($path))
-			{
-				$this->addFile($directory . $path);
-			}
-			elseif ($recursive && is_array($path))
-			{
-				$this->addDirectory($directory . $key, true);
-			}
-		}
-
-		return $this;
-	}
-
+	// Additional Handlers
 	//--------------------------------------------------------------------
 
 	/**
@@ -535,23 +313,11 @@ final public function addPaths(array $paths, bool $recursive = true)
 	 */
 	final public function addPath(string $path, bool $recursive = true)
 	{
-		$full = $this->source . $path;
+		$this->add($this->source . $path, $recursive);
 
-		// Test for a directory
-		try
-		{
-			$directory = self::resolveDirectory($full);
-		}
-		catch (PublisherException $e)
-		{
-			return $this->addFile($full);
-		}
-
-		return $this->addDirectory($full, $recursive);
+		return $this;
 	}
 
-	//--------------------------------------------------------------------
-
 	/**
 	 * Downloads and stages files from an array of URIs.
 	 *
@@ -588,53 +354,7 @@ final public function addUri(string $uri)
 	}
 
 	//--------------------------------------------------------------------
-
-	/**
-	 * Removes any files from the list that match the supplied pattern
-	 * (within the optional scope).
-	 *
-	 * @param string      $pattern Regex or pseudo-regex string
-	 * @param string|null $scope The directory to limit the scope
-	 *
-	 * @return $this
-	 */
-	final public function removePattern(string $pattern, string $scope = null)
-	{
-		if ($pattern === '')
-		{
-			return $this;
-		}
-
-		// Start with all files or those in scope
-		$files = is_null($scope) ? $this->files : self::filterFiles($this->files, $scope);
-
-		// Remove any files that match the pattern
-		return $this->removeFiles(self::matchFiles($files, $pattern));
-	}
-
-	/**
-	 * Keeps only the files from the list that match
-	 * (within the optional scope).
-	 *
-	 * @param string      $pattern Regex or pseudo-regex string
-	 * @param string|null $scope A directory to limit the scope
-	 *
-	 * @return $this
-	 */
-	final public function retainPattern(string $pattern, string $scope = null)
-	{
-		if ($pattern === '')
-		{
-			return $this;
-		}
-
-		// Start with all files or those in scope
-		$files = is_null($scope) ? $this->files : self::filterFiles($this->files, $scope);
-
-		// Matches the pattern within the scoped files and remove their inverse.
-		return $this->removeFiles(array_diff($files, self::matchFiles($files, $pattern)));
-	}
-
+	// Write Methods
 	//--------------------------------------------------------------------
 
 	/**
@@ -649,8 +369,6 @@ final public function wipe()
 		return $this;
 	}
 
-	//--------------------------------------------------------------------
-
 	/**
 	 * Copies all files into the destination, does not create directory structure.
 	 *
@@ -662,7 +380,7 @@ final public function copy(bool $replace = true): bool
 	{
 		$this->errors = $this->published = [];
 
-		foreach ($this->getFiles() as $file)
+		foreach ($this->get() as $file)
 		{
 			$to = $this->destination . basename($file);
 
@@ -693,7 +411,7 @@ final public function merge(bool $replace = true): bool
 		$this->errors = $this->published = [];
 
 		// Get the files from source for special handling
-		$sourced = self::filterFiles($this->getFiles(), $this->source);
+		$sourced = self::filterFiles($this->get(), $this->source);
 
 		// Handle everything else with a flat copy
 		$this->files = array_diff($this->files, $sourced);
diff --git a/tests/system/Files/FileCollectionTest.php b/tests/system/Files/FileCollectionTest.php
new file mode 100644
index 000000000000..ae2df9178f5f
--- /dev/null
+++ b/tests/system/Files/FileCollectionTest.php
@@ -0,0 +1,568 @@
+<?php
+
+use CodeIgniter\Files\Exceptions\FileException;
+use CodeIgniter\Files\File;
+use CodeIgniter\Files\FileCollection;
+use CodeIgniter\Test\CIUnitTestCase;
+
+class FileCollectionTest extends CIUnitTestCase
+{
+	/**
+	 * A known, valid file
+	 *
+	 * @var string
+	 */
+	private $file = SUPPORTPATH . 'Files/baker/banana.php';
+
+	/**
+	 * A known, valid directory
+	 *
+	 * @var string
+	 */
+	private $directory = SUPPORTPATH . 'Files/able/';
+
+	/**
+	 * Initialize the helper, since some
+	 * tests call static methods before
+	 * the constructor would load it.
+	 */
+	public static function setUpBeforeClass(): void
+	{
+		parent::setUpBeforeClass();
+
+		helper(['filesystem']);
+	}
+
+	//--------------------------------------------------------------------
+
+	public function testResolveDirectoryDirectory()
+	{
+		$method = $this->getPrivateMethodInvoker(FileCollection::class, 'resolveDirectory');
+
+		$this->assertSame($this->directory, $method($this->directory));
+	}
+
+	public function testResolveDirectoryFile()
+	{
+		$method = $this->getPrivateMethodInvoker(FileCollection::class, 'resolveDirectory');
+
+		$this->expectException(FileException::class);
+		$this->expectExceptionMessage(lang('Files.expectedDirectory', ['invokeArgs']));
+
+		$method($this->file);
+	}
+
+	public function testResolveDirectorySymlink()
+	{
+		// Create a symlink to test
+		$link = sys_get_temp_dir() . DIRECTORY_SEPARATOR . bin2hex(random_bytes(4));
+		symlink($this->directory, $link);
+
+		$method = $this->getPrivateMethodInvoker(FileCollection::class, 'resolveDirectory');
+
+		$this->assertSame($this->directory, $method($link));
+
+		unlink($link);
+	}
+
+	//--------------------------------------------------------------------
+
+	public function testResolveFileFile()
+	{
+		$method = $this->getPrivateMethodInvoker(FileCollection::class, 'resolveFile');
+
+		$this->assertSame($this->file, $method($this->file));
+	}
+
+	public function testResolveFileSymlink()
+	{
+		// Create a symlink to test
+		$link = sys_get_temp_dir() . DIRECTORY_SEPARATOR . bin2hex(random_bytes(4));
+		symlink($this->file, $link);
+
+		$method = $this->getPrivateMethodInvoker(FileCollection::class, 'resolveFile');
+
+		$this->assertSame($this->file, $method($link));
+
+		unlink($link);
+	}
+
+	public function testResolveFileDirectory()
+	{
+		$method = $this->getPrivateMethodInvoker(FileCollection::class, 'resolveFile');
+
+		$this->expectException(FileException::class);
+		$this->expectExceptionMessage(lang('Files.expectedFile', ['invokeArgs']));
+
+		$method($this->directory);
+	}
+
+	//--------------------------------------------------------------------
+
+	public function testConstructorAddsFiles()
+	{
+		$expected = [
+			$this->directory . 'apple.php',
+			$this->file,
+		];
+
+		$collection = new class([$this->file]) extends FileCollection {
+
+			protected $files = [
+				SUPPORTPATH . 'Files/able/apple.php',
+			];
+		};
+
+		$this->assertSame($expected, $collection->get());
+	}
+
+	public function testConstructorCallsDefine()
+	{
+		$collection = new class() extends FileCollection {
+
+			protected function define(): void
+			{
+				$this->add(SUPPORTPATH . 'Files/baker/banana.php');
+			}
+		};
+
+		$this->assertSame([$this->file], $collection->get());
+	}
+
+	//--------------------------------------------------------------------
+
+	public function testAddStringFile()
+	{
+		$files = new FileCollection();
+
+		$files->add(SUPPORTPATH . 'Files/baker/banana.php');
+
+		$this->assertSame([$this->file], $files->get());
+	}
+
+	public function testAddStringFileRecursiveDoesNothing()
+	{
+		$files = new FileCollection();
+
+		$files->add(SUPPORTPATH . 'Files/baker/banana.php', true);
+
+		$this->assertSame([$this->file], $files->get());
+	}
+
+	public function testAddStringDirectory()
+	{
+		$files = new FileCollection();
+
+		$expected = [
+			$this->directory . 'apple.php',
+			$this->directory . 'fig_3.php',
+			$this->directory . 'prune_ripe.php',
+		];
+
+		$files->add(SUPPORTPATH . 'Files/able');
+
+		$this->assertSame($expected, $files->get());
+	}
+
+	public function testAddStringDirectoryRecursive()
+	{
+		$files = new FileCollection();
+
+		$expected = [
+			$this->directory . 'apple.php',
+			$this->directory . 'fig_3.php',
+			$this->directory . 'prune_ripe.php',
+			SUPPORTPATH . 'Files/baker/banana.php',
+		];
+
+		$files->add(SUPPORTPATH . 'Files');
+
+		$this->assertSame($expected, $files->get());
+	}
+
+	public function testAddArray()
+	{
+		$files = new FileCollection();
+
+		$expected = [
+			$this->directory . 'apple.php',
+			$this->directory . 'fig_3.php',
+			$this->directory . 'prune_ripe.php',
+			SUPPORTPATH . 'Files/baker/banana.php',
+		];
+
+		$files->add([
+			SUPPORTPATH . 'Files/able',
+			SUPPORTPATH . 'Files/baker/banana.php',
+		]);
+
+		$this->assertSame($expected, $files->get());
+	}
+
+	public function testAddArrayRecursive()
+	{
+		$files = new FileCollection();
+
+		$expected = [
+			$this->directory . 'apple.php',
+			$this->directory . 'fig_3.php',
+			$this->directory . 'prune_ripe.php',
+			SUPPORTPATH . 'Files/baker/banana.php',
+			SUPPORTPATH . 'Log/Handlers/TestHandler.php',
+		];
+
+		$files->add([
+			SUPPORTPATH . 'Files',
+			SUPPORTPATH . 'Log',
+		], true);
+
+		$this->assertSame($expected, $files->get());
+	}
+
+	//--------------------------------------------------------------------
+
+	public function testAddFile()
+	{
+		$collection = new FileCollection();
+		$this->assertSame([], $this->getPrivateProperty($collection, 'files'));
+
+		$collection->addFile($this->file);
+		$this->assertSame([$this->file], $this->getPrivateProperty($collection, 'files'));
+	}
+
+	public function testAddFileMissing()
+	{
+		$collection = new FileCollection();
+
+		$this->expectException(FileException::class);
+		$this->expectExceptionMessage(lang('Files.expectedFile', ['addFile']));
+
+		$collection->addFile('TheHillsAreAlive.bmp');
+	}
+
+	public function testAddFileDirectory()
+	{
+		$collection = new FileCollection();
+
+		$this->expectException(FileException::class);
+		$this->expectExceptionMessage(lang('Files.expectedFile', ['addFile']));
+
+		$collection->addFile($this->directory);
+	}
+
+	public function testAddFiles()
+	{
+		$collection = new FileCollection();
+		$files     = [
+			$this->file,
+			$this->file,
+		];
+
+		$collection->addFiles($files);
+		$this->assertSame($files, $this->getPrivateProperty($collection, 'files'));
+	}
+
+	//--------------------------------------------------------------------
+
+	public function testGet()
+	{
+		$collection = new FileCollection();
+		$collection->addFile($this->file);
+
+		$this->assertSame([$this->file], $collection->get());
+	}
+
+	public function testGetSorts()
+	{
+		$collection = new FileCollection();
+		$files     = [
+			$this->file,
+			$this->directory . 'apple.php',
+		];
+
+		$collection->addFiles($files);
+
+		$this->assertSame(array_reverse($files), $collection->get());
+	}
+
+	public function testGetUniques()
+	{
+		$collection = new FileCollection();
+		$files     = [
+			$this->file,
+			$this->file,
+		];
+
+		$collection->addFiles($files);
+		$this->assertSame([$this->file], $collection->get());
+	}
+
+	public function testSet()
+	{
+		$collection = new FileCollection();
+
+		$collection->set([$this->file]);
+		$this->assertSame([$this->file], $collection->get());
+	}
+
+	public function testSetInvalid()
+	{
+		$collection = new FileCollection();
+
+		$this->expectException(FileException::class);
+		$this->expectExceptionMessage(lang('Files.expectedFile', ['addFile']));
+
+		$collection->set(['flerb']);
+	}
+
+	//--------------------------------------------------------------------
+
+	public function testRemoveFile()
+	{
+		$collection = new FileCollection();
+		$files     = [
+			$this->file,
+			$this->directory . 'apple.php',
+		];
+
+		$collection->addFiles($files);
+
+		$collection->removeFile($this->file);
+
+		$this->assertSame([$this->directory . 'apple.php'], $collection->get());
+	}
+
+	public function testRemoveFiles()
+	{
+		$collection = new FileCollection();
+		$files     = [
+			$this->file,
+			$this->directory . 'apple.php',
+		];
+
+		$collection->addFiles($files);
+
+		$collection->removeFiles($files);
+
+		$this->assertSame([], $collection->get());
+	}
+
+	//--------------------------------------------------------------------
+
+	public function testAddDirectoryInvalid()
+	{
+		$collection = new FileCollection();
+
+		$this->expectException(FileException::class);
+		$this->expectExceptionMessage(lang('Files.expectedDirectory', ['addDirectory']));
+
+		$collection->addDirectory($this->file);
+	}
+
+	public function testAddDirectory()
+	{
+		$collection = new FileCollection();
+		$expected  = [
+			$this->directory . 'apple.php',
+			$this->directory . 'fig_3.php',
+			$this->directory . 'prune_ripe.php',
+		];
+
+		$collection->addDirectory($this->directory);
+
+		$this->assertSame($expected, $collection->get());
+	}
+
+	public function testAddDirectoryRecursive()
+	{
+		$collection = new FileCollection();
+		$expected  = [
+			$this->directory . 'apple.php',
+			$this->directory . 'fig_3.php',
+			$this->directory . 'prune_ripe.php',
+			SUPPORTPATH . 'Files/baker/banana.php',
+		];
+
+		$collection->addDirectory(SUPPORTPATH . 'Files', true);
+
+		$this->assertSame($expected, $collection->get());
+	}
+
+	public function testAddDirectories()
+	{
+		$collection = new FileCollection();
+		$expected  = [
+			$this->directory . 'apple.php',
+			$this->directory . 'fig_3.php',
+			$this->directory . 'prune_ripe.php',
+			SUPPORTPATH . 'Files/baker/banana.php',
+		];
+
+		$collection->addDirectories([
+			$this->directory,
+			SUPPORTPATH . 'Files/baker',
+		]);
+
+		$this->assertSame($expected, $collection->get());
+	}
+
+	public function testAddDirectoriesRecursive()
+	{
+		$collection = new FileCollection();
+		$expected  = [
+			$this->directory . 'apple.php',
+			$this->directory . 'fig_3.php',
+			$this->directory . 'prune_ripe.php',
+			SUPPORTPATH . 'Files/baker/banana.php',
+			SUPPORTPATH . 'Log/Handlers/TestHandler.php',
+		];
+
+		$collection->addDirectories([
+			SUPPORTPATH . 'Files',
+			SUPPORTPATH . 'Log',
+		], true);
+
+		$this->assertSame($expected, $collection->get());
+	}
+
+	//--------------------------------------------------------------------
+
+	public function testRemovePatternEmpty()
+	{
+		$collection = new FileCollection();
+		$collection->addDirectory(SUPPORTPATH . 'Files', true);
+
+		$files = $collection->get();
+
+		$collection->removePattern('');
+
+		$this->assertSame($files, $collection->get());
+	}
+
+	public function testRemovePatternRegex()
+	{
+		$collection = new FileCollection();
+		$collection->addDirectory(SUPPORTPATH . 'Files', true);
+
+		$expected = [
+			$this->directory . 'apple.php',
+			SUPPORTPATH . 'Files/baker/banana.php',
+		];
+
+		$collection->removePattern('#[a-z]+_.*#');
+
+		$this->assertSame($expected, $collection->get());
+	}
+
+	public function testRemovePatternPseudo()
+	{
+		$collection = new FileCollection();
+		$collection->addDirectory(SUPPORTPATH . 'Files', true);
+
+		$expected = [
+			$this->directory . 'apple.php',
+			SUPPORTPATH . 'Files/baker/banana.php',
+		];
+
+		$collection->removePattern('*_*.php');
+
+		$this->assertSame($expected, $collection->get());
+	}
+
+	public function testRemovePatternScope()
+	{
+		$collection = new FileCollection();
+		$collection->addDirectory(SUPPORTPATH . 'Files', true);
+
+		$expected = [
+			SUPPORTPATH . 'Files/baker/banana.php',
+		];
+
+		$collection->removePattern('*.php', $this->directory);
+
+		$this->assertSame($expected, $collection->get());
+	}
+
+	//--------------------------------------------------------------------
+
+	public function testRetainPatternEmpty()
+	{
+		$collection = new FileCollection();
+		$collection->addDirectory(SUPPORTPATH . 'Files', true);
+
+		$files = $collection->get();
+
+		$collection->retainPattern('');
+
+		$this->assertSame($files, $collection->get());
+	}
+
+	public function testRetainPatternRegex()
+	{
+		$collection = new FileCollection();
+		$collection->addDirectory(SUPPORTPATH . 'Files', true);
+
+		$expected = [
+			$this->directory . 'fig_3.php',
+			$this->directory . 'prune_ripe.php',
+		];
+
+		$collection->retainPattern('#[a-z]+_.*#');
+
+		$this->assertSame($expected, $collection->get());
+	}
+
+	public function testRetainPatternPseudo()
+	{
+		$collection = new FileCollection();
+		$collection->addDirectory(SUPPORTPATH . 'Files', true);
+
+		$expected = [
+			$this->directory . 'fig_3.php',
+		];
+
+		$collection->retainPattern('*_?.php');
+
+		$this->assertSame($expected, $collection->get());
+	}
+
+	public function testRetainPatternScope()
+	{
+		$collection = new FileCollection();
+		$collection->addDirectory(SUPPORTPATH . 'Files', true);
+
+		$expected = [
+			$this->directory . 'fig_3.php',
+			SUPPORTPATH . 'Files/baker/banana.php',
+		];
+
+		$collection->retainPattern('*_?.php', $this->directory);
+
+		$this->assertSame($expected, $collection->get());
+	}
+
+	//--------------------------------------------------------------------
+
+	public function testCount()
+	{
+		$collection = new FileCollection();
+		$collection->addDirectory(SUPPORTPATH . 'Files', true);
+
+		$this->assertCount(4, $collection);
+	}
+
+	public function testIterable()
+	{
+		$collection = new FileCollection();
+		$collection->addDirectory(SUPPORTPATH . 'Files', true);
+
+		$count = 0;
+		foreach ($collection as $file)
+		{
+			$this->assertInstanceOf(File::class, $file);
+			$count++;
+		}
+
+		$this->assertSame($count, 4);
+	}	
+}
diff --git a/tests/system/Publisher/PublisherInputTest.php b/tests/system/Publisher/PublisherInputTest.php
index e7450f5c02a9..29d48ef78816 100644
--- a/tests/system/Publisher/PublisherInputTest.php
+++ b/tests/system/Publisher/PublisherInputTest.php
@@ -35,219 +35,13 @@ public static function setUpBeforeClass(): void
 
 	//--------------------------------------------------------------------
 
-	public function testAddFile()
-	{
-		$publisher = new Publisher();
-		$this->assertSame([], $this->getPrivateProperty($publisher, 'files'));
-
-		$publisher->addFile($this->file);
-		$this->assertSame([$this->file], $this->getPrivateProperty($publisher, 'files'));
-	}
-
-	public function testAddFileMissing()
-	{
-		$publisher = new Publisher();
-
-		$this->expectException(PublisherException::class);
-		$this->expectExceptionMessage(lang('Publisher.expectedFile', ['addFile']));
-
-		$publisher->addFile('TheHillsAreAlive.bmp');
-	}
-
-	public function testAddFileDirectory()
-	{
-		$publisher = new Publisher();
-
-		$this->expectException(PublisherException::class);
-		$this->expectExceptionMessage(lang('Publisher.expectedFile', ['addFile']));
-
-		$publisher->addFile($this->directory);
-	}
-
-	public function testAddFiles()
-	{
-		$publisher = new Publisher();
-		$files     = [
-			$this->file,
-			$this->file,
-		];
-
-		$publisher->addFiles($files);
-		$this->assertSame($files, $this->getPrivateProperty($publisher, 'files'));
-	}
-
-	//--------------------------------------------------------------------
-
-	public function testGetFiles()
-	{
-		$publisher = new Publisher();
-		$publisher->addFile($this->file);
-
-		$this->assertSame([$this->file], $publisher->getFiles());
-	}
-
-	public function testGetFilesSorts()
-	{
-		$publisher = new Publisher();
-		$files     = [
-			$this->file,
-			$this->directory . 'apple.php',
-		];
-
-		$publisher->addFiles($files);
-
-		$this->assertSame(array_reverse($files), $publisher->getFiles());
-	}
-
-	public function testGetFilesUniques()
-	{
-		$publisher = new Publisher();
-		$files     = [
-			$this->file,
-			$this->file,
-		];
-
-		$publisher->addFiles($files);
-		$this->assertSame([$this->file], $publisher->getFiles());
-	}
-
-	public function testSetFiles()
-	{
-		$publisher = new Publisher();
-
-		$publisher->setFiles([$this->file]);
-		$this->assertSame([$this->file], $publisher->getFiles());
-	}
-
-	public function testSetFilesInvalid()
-	{
-		$publisher = new Publisher();
-
-		$this->expectException(PublisherException::class);
-		$this->expectExceptionMessage(lang('Publisher.expectedFile', ['addFile']));
-
-		$publisher->setFiles(['flerb']);
-	}
-
-	//--------------------------------------------------------------------
-
-	public function testRemoveFile()
-	{
-		$publisher = new Publisher();
-		$files     = [
-			$this->file,
-			$this->directory . 'apple.php',
-		];
-
-		$publisher->addFiles($files);
-
-		$publisher->removeFile($this->file);
-
-		$this->assertSame([$this->directory . 'apple.php'], $publisher->getFiles());
-	}
-
-	public function testRemoveFiles()
-	{
-		$publisher = new Publisher();
-		$files     = [
-			$this->file,
-			$this->directory . 'apple.php',
-		];
-
-		$publisher->addFiles($files);
-
-		$publisher->removeFiles($files);
-
-		$this->assertSame([], $publisher->getFiles());
-	}
-
-	//--------------------------------------------------------------------
-
-	public function testAddDirectoryInvalid()
-	{
-		$publisher = new Publisher();
-
-		$this->expectException(PublisherException::class);
-		$this->expectExceptionMessage(lang('Publisher.expectedDirectory', ['addDirectory']));
-
-		$publisher->addDirectory($this->file);
-	}
-
-	public function testAddDirectory()
-	{
-		$publisher = new Publisher();
-		$expected  = [
-			$this->directory . 'apple.php',
-			$this->directory . 'fig_3.php',
-			$this->directory . 'prune_ripe.php',
-		];
-
-		$publisher->addDirectory($this->directory);
-
-		$this->assertSame($expected, $publisher->getFiles());
-	}
-
-	public function testAddDirectoryRecursive()
-	{
-		$publisher = new Publisher();
-		$expected  = [
-			$this->directory . 'apple.php',
-			$this->directory . 'fig_3.php',
-			$this->directory . 'prune_ripe.php',
-			SUPPORTPATH . 'Files/baker/banana.php',
-		];
-
-		$publisher->addDirectory(SUPPORTPATH . 'Files', true);
-
-		$this->assertSame($expected, $publisher->getFiles());
-	}
-
-	public function testAddDirectories()
-	{
-		$publisher = new Publisher();
-		$expected  = [
-			$this->directory . 'apple.php',
-			$this->directory . 'fig_3.php',
-			$this->directory . 'prune_ripe.php',
-			SUPPORTPATH . 'Files/baker/banana.php',
-		];
-
-		$publisher->addDirectories([
-			$this->directory,
-			SUPPORTPATH . 'Files/baker',
-		]);
-
-		$this->assertSame($expected, $publisher->getFiles());
-	}
-
-	public function testAddDirectoriesRecursive()
-	{
-		$publisher = new Publisher();
-		$expected  = [
-			$this->directory . 'apple.php',
-			$this->directory . 'fig_3.php',
-			$this->directory . 'prune_ripe.php',
-			SUPPORTPATH . 'Files/baker/banana.php',
-			SUPPORTPATH . 'Log/Handlers/TestHandler.php',
-		];
-
-		$publisher->addDirectories([
-			SUPPORTPATH . 'Files',
-			SUPPORTPATH . 'Log',
-		], true);
-
-		$this->assertSame($expected, $publisher->getFiles());
-	}
-
-	//--------------------------------------------------------------------
-
 	public function testAddPathFile()
 	{
 		$publisher = new Publisher(SUPPORTPATH . 'Files');
 
 		$publisher->addPath('baker/banana.php');
 
-		$this->assertSame([$this->file], $publisher->getFiles());
+		$this->assertSame([$this->file], $publisher->get());
 	}
 
 	public function testAddPathFileRecursiveDoesNothing()
@@ -256,7 +50,7 @@ public function testAddPathFileRecursiveDoesNothing()
 
 		$publisher->addPath('baker/banana.php', true);
 
-		$this->assertSame([$this->file], $publisher->getFiles());
+		$this->assertSame([$this->file], $publisher->get());
 	}
 
 	public function testAddPathDirectory()
@@ -271,7 +65,7 @@ public function testAddPathDirectory()
 
 		$publisher->addPath('able');
 
-		$this->assertSame($expected, $publisher->getFiles());
+		$this->assertSame($expected, $publisher->get());
 	}
 
 	public function testAddPathDirectoryRecursive()
@@ -287,7 +81,7 @@ public function testAddPathDirectoryRecursive()
 
 		$publisher->addPath('Files');
 
-		$this->assertSame($expected, $publisher->getFiles());
+		$this->assertSame($expected, $publisher->get());
 	}
 
 	public function testAddPaths()
@@ -306,7 +100,7 @@ public function testAddPaths()
 			'baker/banana.php',
 		]);
 
-		$this->assertSame($expected, $publisher->getFiles());
+		$this->assertSame($expected, $publisher->get());
 	}
 
 	public function testAddPathsRecursive()
@@ -326,7 +120,7 @@ public function testAddPathsRecursive()
 			'Log',
 		], true);
 
-		$this->assertSame($expected, $publisher->getFiles());
+		$this->assertSame($expected, $publisher->get());
 	}
 
 	//--------------------------------------------------------------------
@@ -338,7 +132,7 @@ public function testAddUri()
 
 		$scratch = $this->getPrivateProperty($publisher, 'scratch');
 
-		$this->assertSame([$scratch . 'composer.json'], $publisher->getFiles());
+		$this->assertSame([$scratch . 'composer.json'], $publisher->get());
 	}
 
 	public function testAddUris()
@@ -351,122 +145,6 @@ public function testAddUris()
 
 		$scratch = $this->getPrivateProperty($publisher, 'scratch');
 
-		$this->assertSame([$scratch . 'LICENSE', $scratch . 'composer.json'], $publisher->getFiles());
-	}
-
-	//--------------------------------------------------------------------
-
-	public function testRemovePatternEmpty()
-	{
-		$publisher = new Publisher();
-		$publisher->addDirectory(SUPPORTPATH . 'Files', true);
-
-		$files = $publisher->getFiles();
-
-		$publisher->removePattern('');
-
-		$this->assertSame($files, $publisher->getFiles());
-	}
-
-	public function testRemovePatternRegex()
-	{
-		$publisher = new Publisher();
-		$publisher->addDirectory(SUPPORTPATH . 'Files', true);
-
-		$expected = [
-			$this->directory . 'apple.php',
-			SUPPORTPATH . 'Files/baker/banana.php',
-		];
-
-		$publisher->removePattern('#[a-z]+_.*#');
-
-		$this->assertSame($expected, $publisher->getFiles());
-	}
-
-	public function testRemovePatternPseudo()
-	{
-		$publisher = new Publisher();
-		$publisher->addDirectory(SUPPORTPATH . 'Files', true);
-
-		$expected = [
-			$this->directory . 'apple.php',
-			SUPPORTPATH . 'Files/baker/banana.php',
-		];
-
-		$publisher->removePattern('*_*.php');
-
-		$this->assertSame($expected, $publisher->getFiles());
-	}
-
-	public function testRemovePatternScope()
-	{
-		$publisher = new Publisher();
-		$publisher->addDirectory(SUPPORTPATH . 'Files', true);
-
-		$expected = [
-			SUPPORTPATH . 'Files/baker/banana.php',
-		];
-
-		$publisher->removePattern('*.php', $this->directory);
-
-		$this->assertSame($expected, $publisher->getFiles());
-	}
-
-	//--------------------------------------------------------------------
-
-	public function testRetainPatternEmpty()
-	{
-		$publisher = new Publisher();
-		$publisher->addDirectory(SUPPORTPATH . 'Files', true);
-
-		$files = $publisher->getFiles();
-
-		$publisher->retainPattern('');
-
-		$this->assertSame($files, $publisher->getFiles());
-	}
-
-	public function testRetainPatternRegex()
-	{
-		$publisher = new Publisher();
-		$publisher->addDirectory(SUPPORTPATH . 'Files', true);
-
-		$expected = [
-			$this->directory . 'fig_3.php',
-			$this->directory . 'prune_ripe.php',
-		];
-
-		$publisher->retainPattern('#[a-z]+_.*#');
-
-		$this->assertSame($expected, $publisher->getFiles());
-	}
-
-	public function testRetainPatternPseudo()
-	{
-		$publisher = new Publisher();
-		$publisher->addDirectory(SUPPORTPATH . 'Files', true);
-
-		$expected = [
-			$this->directory . 'fig_3.php',
-		];
-
-		$publisher->retainPattern('*_?.php');
-
-		$this->assertSame($expected, $publisher->getFiles());
-	}
-
-	public function testRetainPatternScope()
-	{
-		$publisher = new Publisher();
-		$publisher->addDirectory(SUPPORTPATH . 'Files', true);
-
-		$expected = [
-			$this->directory . 'fig_3.php',
-			SUPPORTPATH . 'Files/baker/banana.php',
-		];
-
-		$publisher->retainPattern('*_?.php', $this->directory);
-
-		$this->assertSame($expected, $publisher->getFiles());
+		$this->assertSame([$scratch . 'LICENSE', $scratch . 'composer.json'], $publisher->get());
 	}
 }
diff --git a/tests/system/Publisher/PublisherSupportTest.php b/tests/system/Publisher/PublisherSupportTest.php
index 42f22d721525..081b831f1241 100644
--- a/tests/system/Publisher/PublisherSupportTest.php
+++ b/tests/system/Publisher/PublisherSupportTest.php
@@ -53,75 +53,11 @@ public function testDiscoverNothing()
 	public function testDiscoverStores()
 	{
 		$publisher = Publisher::discover()[0];
-		$publisher->setFiles([])->addFile($this->file);
+		$publisher->set([])->addFile($this->file);
 
 		$result = Publisher::discover();
 		$this->assertSame($publisher, $result[0]);
-		$this->assertSame([$this->file], $result[0]->getFiles());
-	}
-
-	//--------------------------------------------------------------------
-
-	public function testResolveDirectoryDirectory()
-	{
-		$method = $this->getPrivateMethodInvoker(Publisher::class, 'resolveDirectory');
-
-		$this->assertSame($this->directory, $method($this->directory));
-	}
-
-	public function testResolveDirectoryFile()
-	{
-		$method = $this->getPrivateMethodInvoker(Publisher::class, 'resolveDirectory');
-
-		$this->expectException(PublisherException::class);
-		$this->expectExceptionMessage(lang('Publisher.expectedDirectory', ['invokeArgs']));
-
-		$method($this->file);
-	}
-
-	public function testResolveDirectorySymlink()
-	{
-		// Create a symlink to test
-		$link = sys_get_temp_dir() . DIRECTORY_SEPARATOR . bin2hex(random_bytes(4));
-		symlink($this->directory, $link);
-
-		$method = $this->getPrivateMethodInvoker(Publisher::class, 'resolveDirectory');
-
-		$this->assertSame($this->directory, $method($link));
-
-		unlink($link);
-	}
-
-	//--------------------------------------------------------------------
-
-	public function testResolveFileFile()
-	{
-		$method = $this->getPrivateMethodInvoker(Publisher::class, 'resolveFile');
-
-		$this->assertSame($this->file, $method($this->file));
-	}
-
-	public function testResolveFileSymlink()
-	{
-		// Create a symlink to test
-		$link = sys_get_temp_dir() . DIRECTORY_SEPARATOR . bin2hex(random_bytes(4));
-		symlink($this->file, $link);
-
-		$method = $this->getPrivateMethodInvoker(Publisher::class, 'resolveFile');
-
-		$this->assertSame($this->file, $method($link));
-
-		unlink($link);
-	}
-
-	public function testResolveFileDirectory()
-	{
-		$method = $this->getPrivateMethodInvoker(Publisher::class, 'resolveFile');
-
-		$this->expectException(PublisherException::class);
-		$this->expectExceptionMessage(lang('Publisher.expectedFile', ['invokeArgs']));
-
-		$method($this->directory);
+		$this->assertSame([$this->file], $result[0]->get());
 	}
 
 	//--------------------------------------------------------------------
diff --git a/user_guide_src/source/libraries/files.rst b/user_guide_src/source/libraries/files.rst
index e6482642d698..c128558c56ab 100644
--- a/user_guide_src/source/libraries/files.rst
+++ b/user_guide_src/source/libraries/files.rst
@@ -109,3 +109,124 @@ The move() method returns a new File instance that for the relocated file, so yo
 resulting location is needed::
 
     $file = $file->move(WRITEPATH.'uploads');
+
+****************
+File Collections
+****************
+
+Working with groups of files can be cumbersome, so the framework supplies the ``FileCollection`` class to facilitate
+locating and working with groups of files across the filesystem. At its most basic, ``FileCollection`` is an index
+of files you set or build::
+
+	$files = new FileCollection([
+		FCPATH . 'index.php',
+		ROOTPATH . 'spark',
+	]);
+	$files->addDirectory(APPPATH . 'Filters');
+
+After you have input the files you would like to work with you may remove files or use the filtering commands to remove
+or retain files matching a certain regex or glob-style pattern::
+
+	$files->removeFile(APPPATH . 'Filters/DevelopToolbar');
+
+	$files->removePattern('#\.gitkeep#');
+	$files->retainPattern('*.php');
+
+When your collection is complete, you can use ``get()`` to retrieve the final list of file paths, or take advantage of
+``FileCollection`` being countable and iterable to work directly with each ``File``::
+
+	echo 'My files: ' . implode(PHP_EOL, $files->get());
+	echo 'I have ' . count($files) . ' files!';
+
+	foreach ($files as $file)
+	{
+		echo 'Moving ' . $file->getBasename() . ', ' . $file->getSizeByUnit('mb');
+		$file->move(WRITABLE . $file->getRandomName()); 
+	}
+
+Below are the specific methods for working with a ``FileCollection``.
+
+Starting a Collection
+=====================
+
+**__construct(string[] $files = [])**
+
+The constructor accepts an optional array of file paths to use as the initial collection. These are passed to
+**add()** so any files supplied by child classes in the **$files** will remain.
+
+**define()**
+
+Allows child classes to define their own initial files. This method is called by the constructor and allows
+predefined collections without having to use their methods. Example::
+
+	class ConfigCollection extends \CodeIgniter\Files\FileCollection
+	{
+		protected function define(): void
+		{
+			$this->add(APPPATH . 'Config', true)->retainPattern('*.php');
+		}
+	}
+
+Now you may use the ``ConfigCollection`` anywhere in your project to access all App Config files without
+having to re-call the collection methods every time.
+
+**set(array $files)**
+
+Sets the list of input files to the provided string array of file paths. This will remove any existing
+files from the collection, so ``$collection->set([])`` is essentially a hard reset.
+
+Inputting Files
+===============
+
+**add(string[]|string $paths, bool $recursive = true)**
+
+Adds all files indicated by the path or array of paths. If the path resolves to a directory then ``$recursive``
+will include sub-directories.
+
+**addFile(string $file)**
+**addFiles(array $files)**
+
+Adds the file or files to the current list of input files. Files are absolute paths to actual files.
+
+**removeFile(string $file)**
+**removeFiles(array $files)**
+
+Removes the file or files from the current list of input files.
+
+**addDirectory(string $directory, bool $recursive = false)**
+**addDirectories(array $directories, bool $recursive = false)**
+
+Adds all files from the directory or directories, optionally recursing into sub-directories. Directories are
+absolute paths to actual directories.
+
+Filtering Files
+===============
+
+**removePattern(string $pattern, string $scope = null)**
+**retainPattern(string $pattern, string $scope = null)**
+
+Filters the current file list through the pattern (and optional scope), removing or retaining matched
+files. ``$pattern`` may be a complete regex (like ``'#[A-Za-z]+\.php#'``) or a pseudo-regex similar
+to ``glob()`` (like ``*.css``).
+If a ``$scope`` is provided then only files in or under that directory will be considered (i.e. files
+outside of ``$scope`` are always retained). When no scope is provided then all files are subject.
+
+Examples::
+
+	$files = new FileCollection();
+	$files->add(APPPATH . 'Config', true); // Adds all Config files and directories
+
+	$files->removePattern('*tion.php'); // Would remove Encryption.php, Validation.php, and boot/production.php
+	$files->removePattern('*tion.php', APPPATH . 'Config/boot'); // Would only remove boot/production.php
+
+	$files->retainPattern('#A.+php$#'); // Would keep only Autoload.php
+	$files->retainPattern('#d.+php$#', APPPATH . 'Config/boot'); // Would keep everything but boot/production.php and boot/testing.php
+
+Retrieving Files
+================
+
+**get(): string[]**
+
+Returns an array of all the loaded input files.
+
+.. note:: ``FileCollection`` is an ``IteratorAggregate`` so you can work with it directly (e.g. ``foreach ($collection as $file)``).
diff --git a/user_guide_src/source/libraries/publisher.rst b/user_guide_src/source/libraries/publisher.rst
index 84b430ba144b..dc2ec08347a8 100644
--- a/user_guide_src/source/libraries/publisher.rst
+++ b/user_guide_src/source/libraries/publisher.rst
@@ -28,8 +28,8 @@ Concept and Usage
 * How can I update my project when the framework or modules change?
 * How can components inject new content into existing projects?
 
-At its most basic, publishing amounts to copying a file or files into a project. ``Publisher`` uses fluent-style
-command chaining to read, filter, and process input files, then copies or merges them into the target destination.
+At its most basic, publishing amounts to copying a file or files into a project. ``Publisher`` extends ``FileCollection``
+to enact fluent-style command chaining to read, filter, and process input files, then copies or merges them into the target destination.
 You may use ``Publisher`` on demand in your Controllers or other components, or you may stage publications by extending
 the class and leveraging its discovery with ``spark publish``.
 
@@ -320,6 +320,8 @@ Now when your module users run ``php spark auth:publish`` they will have the fol
 Library Reference
 *****************
 
+.. note:: ``Publisher`` is an extension of :doc:`FileCollection </libraries/files>` so has access to all those methods for reading and filtering files.
+
 Support Methods
 ===============
 
@@ -346,33 +348,6 @@ files and changes, and this provides the path to a transient, writable directory
 Returns any errors from the last write operation. The array keys are the files that caused the error, and the
 values are the Throwable that was caught. Use ``getMessage()`` on the Throwable to get the error message.
 
-**getFiles(): string[]**
-
-Returns an array of all the loaded input files.
-
-Inputting Files
-===============
-
-**setFiles(array $files)**
-
-Sets the list of input files to the provided string array of file paths.
-
-**addFile(string $file)**
-**addFiles(array $files)**
-
-Adds the file or files to the current list of input files. Files are absolute paths to actual files.
-
-**removeFile(string $file)**
-**removeFiles(array $files)**
-
-Removes the file or files from the current list of input files.
-
-**addDirectory(string $directory, bool $recursive = false)**
-**addDirectories(array $directories, bool $recursive = false)**
-
-Adds all files from the directory or directories, optionally recursing into sub-directories. Directories are
-absolute paths to actual directories.
-
 **addPath(string $path, bool $recursive = true)**
 **addPaths(array $path, bool $recursive = true)**
 
@@ -388,29 +363,6 @@ file to the list.
 .. note:: The CURL request made is a simple ``GET`` and uses the response body for the file contents. Some
 	remote files may need a custom request to be handled properly.
 
-Filtering Files
-===============
-
-**removePattern(string $pattern, string $scope = null)**
-**retainPattern(string $pattern, string $scope = null)**
-
-Filters the current file list through the pattern (and optional scope), removing or retaining matched
-files. ``$pattern`` may be a complete regex (like ``'#[A-Za-z]+\.php#'``) or a pseudo-regex similar
-to ``glob()`` (like ``*.css``).
-If a ``$scope`` is provided then only files in or under that directory will be considered (i.e. files
-outside of ``$scope`` are always retained). When no scope is provided then all files are subject.
-
-Examples::
-
-	$publisher = new Publisher(APPPATH . 'Config');
-	$publisher->addPath('/', true); // Adds all Config files and directories
-
-	$publisher->removePattern('*tion.php'); // Would remove Encryption.php, Validation.php, and boot/production.php
-	$publisher->removePattern('*tion.php', APPPATH . 'Config/boot'); // Would only remove boot/production.php
-
-	$publisher->retainPattern('#A.+php$#'); // Would keep only Autoload.php
-	$publisher->retainPattern('#d.+php$#', APPPATH . 'Config/boot'); // Would keep everything but boot/production.php and boot/testing.php
-
 Outputting Files
 ================