diff --git a/tools/wptrunner/wptrunner/print_pdf_runner.html b/tools/wptrunner/wptrunner/print_pdf_runner.html
index 3ce18d4dd823e0..fbe09bab989d31 100644
--- a/tools/wptrunner/wptrunner/print_pdf_runner.html
+++ b/tools/wptrunner/wptrunner/print_pdf_runner.html
@@ -11,19 +11,19 @@
   let loadingTask = pdfjsLib.getDocument({data: atob(pdfData)});
   let pdf = await loadingTask.promise;
   let rendered = [];
-  for (let pageNumber=1; pageNumber<=pdf.numPages; pageNumber++) {
+  for (let pageNumber = 1; pageNumber <= pdf.numPages; pageNumber++) {
     let page = await pdf.getPage(pageNumber);
-    var viewport = page.getViewport({scale: 96./72.});
+    const viewport = page.getViewport({ scale: 96. / 72. });
     // Prepare canvas using PDF page dimensions
-    var canvas = document.getElementsByTagName('canvas')[0];
-    var context = canvas.getContext('2d');
+    const canvas = document.getElementsByTagName('canvas')[0];
+    const context = canvas.getContext('2d');
     canvas.height = viewport.height;
     canvas.width = viewport.width;
 
     // Render PDF page into canvas context
-    var renderContext = {
+    const renderContext = {
       canvasContext: context,
-      viewport: viewport
+      viewport
     };
     await page.render(renderContext).promise;
     rendered.push(canvas.toDataURL());
diff --git a/webdriver/tests/support/fixtures_bidi.py b/webdriver/tests/support/fixtures_bidi.py
index 39ed3a5bbfd8f7..860db936f93974 100644
--- a/webdriver/tests/support/fixtures_bidi.py
+++ b/webdriver/tests/support/fixtures_bidi.py
@@ -207,8 +207,8 @@ async def assert_pdf_dimensions(pdf, expected_dimensions):
         png = await render_pdf_to_png_bidi(pdf)
         width, height = png_dimensions(png)
 
-        assert cm_to_px(expected_dimensions["height"]) == height
-        assert cm_to_px(expected_dimensions["width"]) == width
+        assert (height - 1) <= cm_to_px(expected_dimensions["height"]) <= (height + 1)
+        assert (width - 1) <= cm_to_px(expected_dimensions["width"]) <= (width + 1)
 
     return assert_pdf_dimensions