diff --git a/filesystem/File.php b/filesystem/File.php
index 576b39dce..a0e92233d 100755
--- a/filesystem/File.php
+++ b/filesystem/File.php
@@ -453,6 +453,7 @@ class File extends DataObject {
 		if($size < 1024*1024) return round($size/1024) . ' KB';
 		if($size < 1024*1024*10) return (round(($size/1024)/1024*10)/10) . ' MB';
 		if($size < 1024*1024*1024) return round(($size/1024)/1024) . ' MB';
+		return round($size/(1024*1024*1024)*10)/10 . ' GB';
 	}
 
 	/**
diff --git a/tests/filesystem/FileTest.php b/tests/filesystem/FileTest.php
new file mode 100644
index 000000000..913d9b1e5
--- /dev/null
+++ b/tests/filesystem/FileTest.php
@@ -0,0 +1,138 @@
+<?php
+
+/**
+ * Tests for the File class
+ */
+class FileTest extends SapphireTest {
+	static $fixture_file = 'sapphire/tests/filesystem/FileTest.yml';
+	
+	function testLinkAndRelativeLink() {
+		$file = $this->objFromFixture('File', 'asdf');
+		$this->assertEquals('assets/asdfjkl.txt', $file->RelativeLink());
+		$this->assertEquals(Director::baseURL() . 'assets/asdfjkl.txt', $file->Link());
+	}
+	
+	function testNameAndTitleGeneration() {
+		/* If objects are loaded into the system with just a Filename, then Name is generated but Title isn't */
+		$file = $this->objFromFixture('File', 'asdf');
+		$this->assertEquals('asdfjkl.txt', $file->Name);
+		$this->assertNull($file->Title);
+		
+		/* However, if Name is set instead of Filename, then Title is set */
+		$file = $this->objFromFixture('File', 'setfromname');
+		$this->assertEquals('assets/asdfjkl.png', $file->Filename);
+		$this->assertEquals('asdfjkl', $file->Title);
+	}
+	
+	function testChangingNameAndFilenameAndParentID() {
+		$file = $this->objFromFixture('File', 'asdf');
+
+		/* If you alter the Name attribute of a file, then the filesystem is also affected */
+		$file->Name = 'asdfjkl2.txt';
+		clearstatcache();
+		$this->assertFileNotExists("../assets/asdfjkl.txt");
+		$this->assertFileExists("../assets/asdfjkl2.txt");
+		/* The Filename field is also updated */
+		$this->assertEquals('assets/asdfjkl2.txt', $file->Filename);
+
+		/* However, if you alter the Filename attribute, the the filesystem isn't affected.  Altering Filename directly isn't
+		recommended */
+		$file->Filename = 'assets/asdfjkl3.txt';
+		clearstatcache();
+		$this->assertFileExists("../assets/asdfjkl2.txt");
+		$this->assertFileNotExists("../assets/asdfjkl3.txt");
+		
+		$file->Filename = 'assets/asdfjkl2.txt';
+		$file->write();
+		
+		/* Instead, altering Name and ParentID is the recommended way of changing the name and location of a file */
+		$file->ParentID = $this->idFromFixture('Folder', 'subfolder');
+		clearstatcache();
+		$this->assertFileExists("../assets/subfolder/asdfjkl2.txt");
+		$this->assertFileNotExists("../assets/asdfjkl2.txt");
+		$this->assertEquals('assets/subfolder/asdfjkl2.txt', $file->Filename);
+		$file->write();
+		
+	}
+	
+	function testSizeAndAbsoluteSizeParameters() {
+		$file = $this->objFromFixture('File', 'asdf');
+		
+		/* AbsoluteSize will give the integer number */
+		$this->assertEquals(1000000, $file->AbsoluteSize);
+		/* Size will give a humanised number */
+		$this->assertEquals('977 KB', $file->Size);
+	}
+	
+	function testFileType() {
+		$file = $this->objFromFixture('File', 'gif');
+		$this->assertEquals("GIF Image - good for diagrams", $file->FileType);
+
+		$file = $this->objFromFixture('File', 'pdf');
+		$this->assertEquals("Adobe Acrobat PDF file", $file->FileType);
+
+		/* Only a few file types are given special descriptions; the rest are unknown */
+		$file = $this->objFromFixture('File', 'asdf');
+		$this->assertEquals("unknown", $file->FileType);
+	}
+	
+	/**
+	 * Test the File::format_size() method
+	 */
+	function testFormatSize() {
+		$this->assertEquals("1000 bytes", File::format_size(1000));
+		$this->assertEquals("1023 bytes", File::format_size(1023));
+		$this->assertEquals("1 KB", File::format_size(1025));
+		$this->assertEquals("9.8 KB", File::format_size(10000));
+		$this->assertEquals("49 KB", File::format_size(50000));
+		$this->assertEquals("977 KB", File::format_size(1000000));
+		$this->assertEquals("1 MB", File::format_size(1024*1024));
+		$this->assertEquals("954 MB", File::format_size(1000000000));
+		$this->assertEquals("1 GB", File::format_size(1024*1024*1024));
+		$this->assertEquals("9.3 GB", File::format_size(10000000000));
+		// It use any denomination higher than GB.  It also doesn't overflow with >32 bit integers
+		$this->assertEquals("93132.3 GB", File::format_size(100000000000000));
+	}
+	
+	/////////////////////////////////////////////////////////////////////////////////////////////////////////////
+	
+	function setUp() {
+		parent::setUp();
+
+		/* Create a test folders for each of the fixture references */
+		$fileIDs = $this->allFixtureIDs('Folder');
+		foreach($fileIDs as $fileID) {
+			$file = DataObject::get_by_id('Folder', $fileID);
+			if(!file_exists("../$file->Filename")) mkdir("../$file->Filename");
+		}
+		
+		/* Create a test files for each of the fixture references */
+		$fileIDs = $this->allFixtureIDs('File');
+		foreach($fileIDs as $fileID) {
+			$file = DataObject::get_by_id('File', $fileID);
+			$fh = fopen("../$file->Filename", "w");
+			fwrite($fh, str_repeat('x',1000000));
+			fclose($fh);
+		}
+	} 
+	
+	function tearDown() {
+		/* Remove the test files that we've created */
+		$fileIDs = $this->allFixtureIDs('File');
+		foreach($fileIDs as $fileID) {
+			$file = DataObject::get_by_id('File', $fileID);
+			if(file_exists("../$file->Filename")) unlink("../$file->Filename");
+		}
+
+		/* Remove the test folders that we've crated */
+		$fileIDs = $this->allFixtureIDs('Folder');
+		foreach($fileIDs as $fileID) {
+			$file = DataObject::get_by_id('Folder', $fileID);
+			if(file_exists("../$file->Filename")) rmdir("../$file->Filename");
+		}
+		
+		parent::tearDown();
+	}
+	
+	
+}
\ No newline at end of file
diff --git a/tests/filesystem/FileTest.yml b/tests/filesystem/FileTest.yml
new file mode 100644
index 000000000..7582fbd46
--- /dev/null
+++ b/tests/filesystem/FileTest.yml
@@ -0,0 +1,14 @@
+File:
+   asdf:
+      Filename: assets/asdfjkl.txt
+   gif:
+      Filename: assets/asdfjkl.gif
+   pdf:
+      Filename: assets/asdfjkl.pdf
+   setfromname:
+      Name: asdfjkl.png
+      ParentID: 0
+
+Folder:
+   subfolder:
+      Name: subfolder
\ No newline at end of file