diff --git a/src/__phutil_library_map__.php b/src/__phutil_library_map__.php
index eab3d46eb7..a1bc47e859 100644
--- a/src/__phutil_library_map__.php
+++ b/src/__phutil_library_map__.php
@@ -896,6 +896,7 @@ phutil_register_library_map(array(
     'PhabricatorFileStorageConfigurationException' => 'applications/files/exception/PhabricatorFileStorageConfigurationException.php',
     'PhabricatorFileStorageEngine' => 'applications/files/engine/PhabricatorFileStorageEngine.php',
     'PhabricatorFileStorageEngineSelector' => 'applications/files/engineselector/PhabricatorFileStorageEngineSelector.php',
+    'PhabricatorFileTestCase' => 'applications/files/storage/__tests__/PhabricatorFileTestCase.php',
     'PhabricatorFileTransformController' => 'applications/files/controller/PhabricatorFileTransformController.php',
     'PhabricatorFileUploadController' => 'applications/files/controller/PhabricatorFileUploadController.php',
     'PhabricatorFileUploadException' => 'applications/files/exception/PhabricatorFileUploadException.php',
@@ -1301,6 +1302,7 @@ phutil_register_library_map(array(
     'PhabricatorTagView' => 'view/layout/PhabricatorTagView.php',
     'PhabricatorTaskmasterDaemon' => 'infrastructure/daemon/workers/PhabricatorTaskmasterDaemon.php',
     'PhabricatorTestCase' => 'infrastructure/testing/PhabricatorTestCase.php',
+    'PhabricatorTestStorageEngine' => 'applications/files/engine/PhabricatorTestStorageEngine.php',
     'PhabricatorTestWorker' => 'infrastructure/daemon/workers/__tests__/PhabricatorTestWorker.php',
     'PhabricatorTimelineCursor' => 'infrastructure/daemon/timeline/storage/PhabricatorTimelineCursor.php',
     'PhabricatorTimelineDAO' => 'infrastructure/daemon/timeline/storage/PhabricatorTimelineDAO.php',
@@ -2338,6 +2340,7 @@ phutil_register_library_map(array(
     'PhabricatorFileShortcutController' => 'PhabricatorFileController',
     'PhabricatorFileStorageBlob' => 'PhabricatorFileDAO',
     'PhabricatorFileStorageConfigurationException' => 'Exception',
+    'PhabricatorFileTestCase' => 'PhabricatorTestCase',
     'PhabricatorFileTransformController' => 'PhabricatorFileController',
     'PhabricatorFileUploadController' => 'PhabricatorFileController',
     'PhabricatorFileUploadException' => 'Exception',
@@ -2703,6 +2706,7 @@ phutil_register_library_map(array(
     'PhabricatorTagView' => 'AphrontView',
     'PhabricatorTaskmasterDaemon' => 'PhabricatorDaemon',
     'PhabricatorTestCase' => 'ArcanistPhutilTestCase',
+    'PhabricatorTestStorageEngine' => 'PhabricatorFileStorageEngine',
     'PhabricatorTestWorker' => 'PhabricatorWorker',
     'PhabricatorTimelineCursor' => 'PhabricatorTimelineDAO',
     'PhabricatorTimelineDAO' => 'PhabricatorLiskDAO',
diff --git a/src/applications/files/engine/PhabricatorTestStorageEngine.php b/src/applications/files/engine/PhabricatorTestStorageEngine.php
new file mode 100644
index 0000000000..af45c6574a
--- /dev/null
+++ b/src/applications/files/engine/PhabricatorTestStorageEngine.php
@@ -0,0 +1,36 @@
+<?php
+
+/**
+ * Test storage engine. Does not actually store files. Used for unit tests.
+ *
+ * @group filestorage
+ */
+final class PhabricatorTestStorageEngine
+  extends PhabricatorFileStorageEngine {
+
+  private static $storage = array();
+  private static $nextHandle = 1;
+
+  public function getEngineIdentifier() {
+    return 'unit-test';
+  }
+
+  public function writeFile($data, array $params) {
+    AphrontWriteGuard::willWrite();
+    self::$storage[self::$nextHandle] = $data;
+    return self::$nextHandle++;
+  }
+
+  public function readFile($handle) {
+    if (isset(self::$storage[$handle])) {
+      return self::$storage[$handle];
+    }
+    throw new Exception("No such file with handle '{$handle}'!");
+  }
+
+  public function deleteFile($handle) {
+    AphrontWriteGuard::willWrite();
+    unset(self::$storage[$handle]);
+  }
+
+}
diff --git a/src/applications/files/storage/PhabricatorFile.php b/src/applications/files/storage/PhabricatorFile.php
index 8a9f486644..4e28e4d3f0 100644
--- a/src/applications/files/storage/PhabricatorFile.php
+++ b/src/applications/files/storage/PhabricatorFile.php
@@ -134,9 +134,16 @@ final class PhabricatorFile extends PhabricatorFileDAO
 
 
   public static function newFromFileData($data, array $params = array()) {
-    $selector = PhabricatorEnv::newObjectFromConfig('storage.engine-selector');
 
-    $engines = $selector->selectStorageEngines($data, $params);
+    if (isset($params['storageEngines'])) {
+      $engines = $params['storageEngines'];
+    } else {
+      $selector = PhabricatorEnv::newObjectFromConfig(
+        'storage.engine-selector');
+      $engines = $selector->selectStorageEngines($data, $params);
+    }
+
+    assert_instances_of($engines, 'PhabricatorFileStorageEngine');
     if (!$engines) {
       throw new Exception("No valid storage engines are available!");
     }
diff --git a/src/applications/files/storage/__tests__/PhabricatorFileTestCase.php b/src/applications/files/storage/__tests__/PhabricatorFileTestCase.php
new file mode 100644
index 0000000000..334d3a92f1
--- /dev/null
+++ b/src/applications/files/storage/__tests__/PhabricatorFileTestCase.php
@@ -0,0 +1,61 @@
+<?php
+
+final class PhabricatorFileTestCase extends PhabricatorTestCase {
+
+  public function getPhabricatorTestCaseConfiguration() {
+    return array(
+      self::PHABRICATOR_TESTCONFIG_BUILD_STORAGE_FIXTURES => true,
+    );
+  }
+
+  public function testFileStorageReadWrite() {
+    $engine = new PhabricatorTestStorageEngine();
+
+    $data = Filesystem::readRandomCharacters(64);
+
+    $params = array(
+      'name' => 'test.dat',
+      'storageEngines' => array(
+        $engine,
+      ),
+    );
+
+    $file = PhabricatorFile::newFromFileData($data, $params);
+
+    // Test that the storage engine worked, and was the target of the write. We
+    // don't actually care what the data is (future changes may compress or
+    // encrypt it), just that it exists in the test storage engine.
+    $engine->readFile($file->getStorageHandle());
+
+    // Now test that we get the same data back out.
+    $this->assertEqual($data, $file->loadFileData());
+  }
+
+
+  public function testFileStorageDelete() {
+    $engine = new PhabricatorTestStorageEngine();
+
+    $data = Filesystem::readRandomCharacters(64);
+
+    $params = array(
+      'name' => 'test.dat',
+      'storageEngines' => array(
+        $engine,
+      ),
+    );
+
+    $file = PhabricatorFile::newFromFileData($data, $params);
+    $handle = $file->getStorageHandle();
+    $file->delete();
+
+    $caught = null;
+    try {
+      $engine->readFile($handle);
+    } catch (Exception $ex) {
+      $caught = $ex;
+    }
+
+    $this->assertEqual(true, $caught instanceof Exception);
+  }
+
+}