diff --git a/tests/FillPdfMergeTestCase.test b/tests/FillPdfMergeTestCase.test
index 269f5fdca9ae4adc544d52052383ea97dde5b51a..356f8479e46eec982a7a358590b8cc83a23e3dac 100644
--- a/tests/FillPdfMergeTestCase.test
+++ b/tests/FillPdfMergeTestCase.test
@@ -534,6 +534,24 @@ class FillPdfMergeTestCase extends ImageFieldTestCase {
     $this->backendTest();
   }
 
+  /**
+   * Tests PDF merging using a local install of pdftk.
+   */
+  public function testPdftkPdfMerging() {
+    $this->configurePdftkBackend();
+    if (!fillpdf_pdftk_check()) {
+      // No pdftk installed, so don't run any assertions.
+      return;
+    }
+
+    // The testing UI doesn't clearly indicate that these tests are being run by
+    // default because we delegate to backendTest(). This is a convenience
+    // marker.
+    $this->assertTrue(TRUE, 'Detected pdftk. Running tests.');
+
+    $this->backendTest();
+  }
+
   /**
    *
    */
diff --git a/tests/FillPdfTestHelper.test b/tests/FillPdfTestHelper.test
index a63b97cbde5ab554cc6e345739c2fd9050b5c483..780724d3a63d40bbc27648ff92dfc47c90a6810e 100644
--- a/tests/FillPdfTestHelper.test
+++ b/tests/FillPdfTestHelper.test
@@ -56,6 +56,14 @@ trait FillPdfTestHelper {
     variable_set('fillpdf_local_service_endpoint', 'http://127.0.0.1:8085');
   }
 
+  /**
+   * Configures FillPdf using the pdftk backend.
+   */
+  protected function configurePdftkBackend() {
+    variable_set('fillpdf_service', 'pdftk');
+    variable_set('fillpdf_scheme', 'private');
+  }
+
   /**
    * Get the fid of the uploaded file to construct the link.
    *