diff --git a/tests/FileTextCacheDatabaseTest.php b/tests/FileTextCacheDatabaseTest.php
index e300c19..e7fb242 100644
--- a/tests/FileTextCacheDatabaseTest.php
+++ b/tests/FileTextCacheDatabaseTest.php
@@ -1,23 +1,23 @@
 <?php
 
-use SilverStripe\TextExtraction\Extension\FileTextCache,
-    SilverStripe\TextExtraction\Extension\FileTextCache_Database,
-    SilverStripe\Dev\SapphireTest,
-    SilverStripe\Core\Config\Config;
+namespace SilverStripe\TextExtraction\Tests;
+
+use SilverStripe\Assets\File;
+use SilverStripe\Core\Config\Config;
+use SilverStripe\Dev\SapphireTest;
+use SilverStripe\TextExtraction\Cache\FileTextCache\Database;
 
 class FileTextCacheDatabaseTest extends SapphireTest
 {
     public function testTruncatesByMaxLength()
     {
-        Config::nest();
+        Config::modify()->set(Database::class, 'max_content_length', 5);
 
-        Config::inst()->update('FileTextCache_Database', 'max_content_length', 5);
-        $cache = new FileTextCache_Database();
-        $file = $this->getMock('File', array('write'));
+        $cache = new Database();
+        $file = $this->getMockBuilder(File::class)->setMethods(['write'])->getMock();
         $content = '0123456789';
         $cache->save($file, $content);
-        $this->assertEquals($cache->load($file), '01234');
 
-        Config::unnest();
+        $this->assertEquals($cache->load($file), '01234');
     }
 }
diff --git a/tests/FileTextExtractableTest.php b/tests/FileTextExtractableTest.php
index 166b1ee..4a1edf2 100644
--- a/tests/FileTextExtractableTest.php
+++ b/tests/FileTextExtractableTest.php
@@ -1,46 +1,53 @@
 <?php
+
+namespace SilverStripe\TextExtraction\Tests;
+
+use SilverStripe\Assets\File;
+use SilverStripe\Core\Config\Config;
+use SilverStripe\Dev\SapphireTest;
+use SilverStripe\TextExtraction\Extension\FileTextExtractable;
+
 class FileTextExtractableTest extends SapphireTest
 {
-    protected $requiredExtensions = array(
-        'File' => array('FileTextExtractable')
-    );
+    protected $usesDatabase = true;
 
-    public function setUp()
+    protected static $required_extensions = [
+        File::class => [
+            FileTextExtractable::class,
+        ],
+    ];
+
+    protected function setUp()
     {
         parent::setUp();
 
         // Ensure that html is a valid extension
-        Config::inst()
-            ->nest()
-            ->update('File', 'allowed_extensions', array('html'));
-    }
-
-    public function tearDown()
-    {
-        Config::unnest();
-        parent::tearDown();
+        Config::modify()->merge(File::class, 'allowed_extensions', ['html']);
     }
 
     public function testExtractFileAsText()
     {
         // Create a copy of the file, as it may be clobbered by the test
         // ($file->extractFileAsText() calls $file->write)
-        copy(BASE_PATH.'/textextraction/tests/fixtures/test1.html', BASE_PATH.'/textextraction/tests/fixtures/test1-copy.html');
-        
+        copy(
+            dirname(__FILE__) . '/fixtures/test1.html',
+            dirname(__FILE__) . '/fixtures/test1-copy.html'
+        );
+
         // Use HTML, since the extractor is always available
-        $file = new File(array(
+        $file = new File([
             'Name' => 'test1-copy.html',
-            'Filename' => 'textextraction/tests/fixtures/test1-copy.html'
-        ));
+            'Filename' => dirname(__FILE__) . '/fixtures/test1-copy.html'
+        ]);
         $file->write();
-    
+
         $content = $file->extractFileAsText();
         $this->assertContains('Test Headline', $content);
         $this->assertContains('Test Text', $content);
         $this->assertEquals($content, $file->FileContentCache);
 
-        if (file_exists(BASE_PATH.'/textextraction/tests/fixtures/test1-copy.html')) {
-            unlink(BASE_PATH.'/textextraction/tests/fixtures/test1-copy.html');
+        if (file_exists(dirname(__FILE__) . '/fixtures/test1-copy.html')) {
+            unlink(dirname(__FILE__) . '/fixtures/test1-copy.html');
         }
     }
 }
diff --git a/tests/HTMLTextExtractorTest.php b/tests/HTMLTextExtractorTest.php
index 8ff8b0b..59b8018 100644
--- a/tests/HTMLTextExtractorTest.php
+++ b/tests/HTMLTextExtractorTest.php
@@ -1,11 +1,18 @@
 <?php
+
+namespace SilverStripe\TextExtraction\Tests;
+
+use SilverStripe\Dev\SapphireTest;
+use SilverStripe\TextExtraction\Extractor\HTMLTextExtractor;
+
 class HTMLTextExtractorTest extends SapphireTest
 {
     public function testExtraction()
     {
         $extractor = new HTMLTextExtractor();
 
-        $content = $extractor->getContent(Director::baseFolder() . '/textextraction/tests/fixtures/test1.html');
+        $content = $extractor->getContent(dirname(__FILE__) . '/fixtures/test1.html');
+
         $this->assertContains('Test Headline', $content);
         $this->assertNotContains('Test Comment', $content, 'Strips HTML comments');
         $this->assertNotContains('Test Style', $content, 'Strips non-content style tags');
diff --git a/tests/PDFTextExtractorTest.php b/tests/PDFTextExtractorTest.php
index 96ad1ec..dfbffcd 100644
--- a/tests/PDFTextExtractorTest.php
+++ b/tests/PDFTextExtractorTest.php
@@ -1,17 +1,22 @@
 <?php
+
+namespace SilverStripe\TextExtraction\Tests;
+
+use SilverStripe\Dev\SapphireTest;
+use SilverStripe\TextExtraction\Extractor\FileTextExtractor\Exception;
+use SilverStripe\TextExtraction\Extractor\PDFTextExtractor;
+
 class PDFTextExtractorTest extends SapphireTest
 {
     public function testExtraction()
     {
         $extractor = new PDFTextExtractor();
         if (!$extractor->isAvailable()) {
-            $this->setExpectedException(
-                'FileTextExtractor_Exception',
-                'getRawOutput called on unavailable extractor'
-            );
+            $this->expectException(Exception::class);
+            $this->expectExceptionMessage('getRawOutput called on unavailable extractor');
         }
 
-        $content = $extractor->getContent(Director::baseFolder() . '/textextraction/tests/fixtures/test1.pdf');
+        $content = $extractor->getContent(dirname(__FILE__) . '/fixtures/test1.pdf');
         $this->assertContains('This is a test file with a link', $content);
     }
 }
diff --git a/tests/TikaTextExtractorTest.php b/tests/TikaTextExtractorTest.php
index 0342dcf..6c8e801 100644
--- a/tests/TikaTextExtractorTest.php
+++ b/tests/TikaTextExtractorTest.php
@@ -1,5 +1,11 @@
 <?php
 
+namespace SilverStripe\TextExtraction\Tests;
+
+use SilverStripe\Dev\SapphireTest;
+use SilverStripe\TextExtraction\Extractor\TikaServerTextExtractor;
+use SilverStripe\TextExtraction\Extractor\TikaTextExtractor;
+
 /**
  * Tests the {@see TikaTextExtractor} class
  */
@@ -13,7 +19,7 @@ class TikaTextExtractorTest extends SapphireTest
         }
 
         // Check file
-        $file = Director::baseFolder() . '/textextraction/tests/fixtures/test1.pdf';
+        $file = dirname(__FILE__) . '/fixtures/test1.pdf';
         $content = $extractor->getContent($file);
         $this->assertContains('This is a test file with a link', $content);
 
@@ -31,7 +37,7 @@ class TikaTextExtractorTest extends SapphireTest
         }
 
         // Check file
-        $file = Director::baseFolder() . '/textextraction/tests/fixtures/test1.pdf';
+        $file = dirname(__FILE__) . '/fixtures/test1.pdf';
         $content = $extractor->getContent($file);
         $this->assertContains('This is a test file with a link', $content);