Added CallbackFileFetcher and LazyStubFileFetcher

README.md

@@ -22,6 +22,8 @@ The library provides some trivial implementations of the `FileFetcher` interface
 * `ThrowingFileFetcher`: Throws a `FileFetchingException` for all calls
 * `NullFileFetcher`: Returns an empty string for all calls
 * `StubFileFetcher`: Returns a stub value for all calls
+* `CallbackFileFetcher`: Adapter around a callback
+* `LazyStubFileFetcher`: Return a lazily retrieved stub value for all calls
 
 It also provides a number of generic [decorators](https://en.wikipedia.org/wiki/Decorator_pattern):
 
@@ -61,6 +63,11 @@ For a full CI run
 
 ## Release notes
 
+### 4.4.0 (2018-05-31)
+
+* Added `CallbackFileFetcher`
+* Added `LazyStubFileFetcher`
+
 ### 4.3.0 (2017-06-10)
 
 * Added `getFirstFetchedUrl` to `SpyingFileFetcher`

src/CallbackFileFetcher.php

@@ -0,0 +1,33 @@
+<?php
+
+declare( strict_types=1 );
+
+namespace FileFetcher;
+
+/**
+ * Callback adapter. Calls to fetchFile are routed to the callback.
+ *
+ * @since 4.4
+ *
+ * @licence GNU GPL v2+
+ * @author Jeroen De Dauw < jeroendedauw@gmail.com >
+ */
+class CallbackFileFetcher implements FileFetcher {
+
+	private $callback;
+
+	/**
+	 * The callback should have the same signature and contract as @see FileFetcher::fetchFile()
+	 * Note that this contract include not throwing exceptions other than FileFetchingException.
+	 *
+	 * @param callable $callback
+	 */
+	public function __construct( callable $callback ) {
+		$this->callback = $callback;
+	}
+
+	public function fetchFile( string $fileUrl ): string {
+		return ($this->callback)( $fileUrl );
+	}
+
+}

src/LazyStubFileFetcher.php

@@ -0,0 +1,26 @@
+<?php
+
+declare( strict_types=1 );
+
+namespace FileFetcher;
+
+/**
+ * @since 4.4
+ *
+ * @licence GNU GPL v2+
+ * @author Jeroen De Dauw < jeroendedauw@gmail.com >
+ */
+class LazyStubFileFetcher {
+
+	private function __construct() {
+	}
+
+	public static function newFromFileUrl( string $fileUrl ): FileFetcher {
+		$fetcher = new SimpleFileFetcher();
+
+		return new CallbackFileFetcher( function() use ( $fetcher, $fileUrl ) {
+			return $fetcher->fetchFile( $fileUrl );
+		} );
+	}
+
+}

tests/integration/LazyStubFileFetcherTest.php

@@ -0,0 +1,25 @@
+<?php
+
+declare( strict_types=1 );
+
+namespace FileFetcher\Tests\Integration;
+
+use FileFetcher\LazyStubFileFetcher;
+use PHPUnit\Framework\TestCase;
+
+/**
+ * @covers \FileFetcher\LazyStubFileFetcher
+ *
+ * @licence GNU GPL v2+
+ * @author Jeroen De Dauw < jeroendedauw@gmail.com >
+ */
+class LazyStubFileFetcherTest extends TestCase {
+
+	public function testCallbackGetsFileUrlAndReturnValueIsReturned() {
+		$this->assertSame(
+			file_get_contents( __FILE__ ),
+			LazyStubFileFetcher::newFromFileUrl( __FILE__ )->fetchFile( 'Whatever' )
+		);
+	}
+
+}

tests/integration/SimpleFileFetcherTest.php

@@ -9,7 +9,7 @@
 use PHPUnit\Framework\TestCase;
 
 /**
- * @covers FileFetcher\SimpleFileFetcher
+ * @covers \FileFetcher\SimpleFileFetcher
  *
  * @licence GNU GPL v2+
  * @author Jeroen De Dauw < jeroendedauw@gmail.com >
@@ -21,7 +21,7 @@ public function testGetThisFileFromDisk() {
 
 		$contents = $fetcher->fetchFile( __FILE__ );
 
-		$this->assertEquals( file_get_contents( __FILE__ ), $contents );
+		$this->assertSame( file_get_contents( __FILE__ ), $contents );
 	}
 
 	public function testGetThisFileFromGitHub() {

tests/unit/CallbackFileFetcherTest.php

@@ -0,0 +1,36 @@
+<?php
+
+declare( strict_types=1 );
+
+namespace FileFetcher\Tests\Phpunit;
+
+use FileFetcher\CallbackFileFetcher;
+use FileFetcher\FileFetchingException;
+use PHPUnit\Framework\TestCase;
+
+/**
+ * @covers \FileFetcher\CallbackFileFetcher
+ *
+ * @licence GNU GPL v2+
+ * @author Jeroen De Dauw < jeroendedauw@gmail.com >
+ */
+class CallbackFileFetcherTest extends TestCase {
+
+	public function testCallbackGetsFileUrlAndReturnValueIsReturned() {
+		$fetcher = new CallbackFileFetcher( function( string $fileUrl ) {
+			return $fileUrl . $fileUrl . $fileUrl;
+		} );
+
+		$this->assertSame( 'SuchSuchSuch', $fetcher->fetchFile( 'Such' ) );
+	}
+
+	public function testCallbackExceptionBubblesUp() {
+		$fetcher = new CallbackFileFetcher( function( string $fileUrl ) {
+			throw new FileFetchingException( $fileUrl );
+		} );
+
+		$this->expectException( FileFetchingException::class );
+		$fetcher->fetchFile( 'Such' );
+	}
+
+}

tests/unit/StubFileFetcherTest.php

@@ -8,7 +8,7 @@
 use PHPUnit\Framework\TestCase;
 
 /**
- * @covers FileFetcher\StubFileFetcher
+ * @covers \FileFetcher\StubFileFetcher
  *
  * @licence GNU GPL v2+
  * @author Jeroen De Dauw < jeroendedauw@gmail.com >