Auto merge of #9293 - Ms2ger:reftests, r=SimonSapin

Remove the legacy reftest framework.

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22 files changed, 228 insertions, 556 deletions

diff --git a/python/servo/testing_commands.py b/python/servo/testing_commands.py
index 875137ff536..9892a0e6669 100644
--- a/python/servo/testing_commands.py
+++ b/python/servo/testing_commands.py
@@ -201,52 +201,11 @@ class MachCommands(CommandBase):
     @Command('test-ref',
              description='Run the reference tests',
              category='testing')
-    @CommandArgument('--kind', '-k', default=DEFAULT_RENDER_MODE,
-                     help=HELP_RENDER_MODE)
-    @CommandArgument('--release', '-r', action='store_true',
-                     help='Run with a release build of Servo')
-    @CommandArgument('--include', default=None, nargs='+',
-                     help="Only run tests that match this pattern. If the "
-                          "path to the ref test directory is included, it "
-                          "will automatically be trimmed out.")
-    @CommandArgument(
-        'servo_params', default=None, nargs=argparse.REMAINDER,
-        help="Command-line arguments to be passed through to Servo")
-    def test_ref(self, kind=DEFAULT_RENDER_MODE, include=None, servo_params=None,
-                 release=False):
-        self.ensure_bootstrapped()
-        self.ensure_built_tests(release=release)
-        assert kind is not None, 'kind cannot be None, see help'
-
-        kinds = ["cpu", "gpu"] if kind == 'both' else [kind]
-        test_path = path.join(self.context.topdir, "tests", "ref")
-        error = False
-
-        test_start = time()
-        for k in kinds:
-            print("Running %s reftests..." % k)
-            test_args = [k, test_path]
-            if include is not None:
-                ref_path = path.join("tests", "ref")
-                for name in include:
-                    # Check to see if we were passed something leading with the
-                    # path to the ref test directory, and trim it so that reftest
-                    # knows how to filter it.
-                    maybe_path = path.normpath(name)
-                    if ref_path in maybe_path:
-                        test_args.append(path.relpath(maybe_path, ref_path))
-                    else:
-                        test_args.append(name)
-            if servo_params is not None:
-                test_args += ["--"] + servo_params
-            ret = self.run_test("reftest", test_args, release=release)
-            error = error or ret != 0
-        elapsed = time() - test_start
-
-        print("Reference tests completed in %0.2fs" % elapsed)
-
-        if error:
-            return 1
+    @CommandArgument('params', default=None, nargs=argparse.REMAINDER)
+    def test_ref(self, params=None):
+        print("Ref tests have been replaced by web-platform-tests under "
+              "tests/wpt/mozilla/.")
+        return 0
 
     @Command('test-content',
              description='Run the content tests',
diff --git a/python/tidy.py b/python/tidy.py
index a3a7bf65ab9..10c07bde16a 100644
--- a/python/tidy.py
+++ b/python/tidy.py
@@ -19,8 +19,6 @@ import sys
 from licenseck import licenses
 
 filetypes_to_check = [".rs", ".rc", ".cpp", ".c", ".h", ".lock", ".py", ".toml", ".webidl"]
-reftest_dir = "./tests/ref"
-reftest_filetype = ".list"
 
 ignored_files = [
     # Upstream
@@ -62,10 +60,6 @@ def should_check(file_name):
     return True
 
 
-def should_check_reftest(file_name):
-    return file_name.endswith(reftest_filetype)
-
-
 EMACS_HEADER = "/* -*- Mode:"
 VIM_HEADER = "/* vim:"
 MAX_LICENSE_LINESPAN = max(len(license.splitlines()) for license in licenses)
@@ -517,44 +511,6 @@ def collect_errors_for_files(files_to_check, checking_functions, line_checking_f
                     yield (filename,) + error
 
 
-def check_reftest_order(files_to_check):
-    for file_name in files_to_check:
-        with open(file_name, "r") as fp:
-            split_lines = fp.read().splitlines()
-            lines = filter(lambda l: len(l) > 0 and l[0] != '#', split_lines)
-            for idx, line in enumerate(lines[:-1]):
-                next_line = lines[idx + 1]
-                current = get_reftest_names(line)
-                next = get_reftest_names(next_line)
-                if current is not None and next is not None and current > next:
-                    yield (file_name, split_lines.index(next_line) + 1, "line not in alphabetical order")
-
-
-def get_reftest_names(line):
-    tokens = line.split()
-    if len(tokens) == 3:
-        return tokens[1] + tokens[2]
-    if len(tokens) == 4:
-        return tokens[2] + tokens[3]
-    return None
-
-
-def get_html_file_names_from_reftest_list(reftest_dir, file_name):
-    for line in open(os.path.join(reftest_dir, file_name), "r"):
-        for token in line.split():
-            if fnmatch.fnmatch(token, '*.html'):
-                yield os.path.join(reftest_dir, token)
-
-
-def check_reftest_html_files_in_basic_list(reftest_dir):
-    basic_list_files = set(get_html_file_names_from_reftest_list(reftest_dir, "basic" + reftest_filetype))
-
-    for file_name in os.listdir(reftest_dir):
-        file_path = os.path.join(reftest_dir, file_name)
-        if fnmatch.fnmatch(file_path, '*.html') and file_path not in basic_list_files:
-            yield (file_path, "", "not found in basic.list")
-
-
 def check_wpt_lint_errors():
     wpt_working_dir = os.path.abspath(os.path.join(".", "tests", "wpt", "web-platform-tests"))
     site.addsitedir(wpt_working_dir)
@@ -586,11 +542,6 @@ def scan(faster=False):
     line_checking_functions = (check_license, check_by_line, check_toml, check_rust, check_spec)
     errors = collect_errors_for_files(files_to_check, checking_functions, line_checking_functions)
 
-    # reftest checks
-    reftest_to_check = filter(should_check_reftest, get_file_list(reftest_dir, faster))
-    r_errors = check_reftest_order(reftest_to_check)
-    not_found_in_basic_list_errors = check_reftest_html_files_in_basic_list(reftest_dir)
-
     # wpt lint checks
     if faster:
         print "\033[93mUsing test-tidy \033[01m--faster\033[22m, skipping WPT lint\033[0m"
@@ -599,7 +550,7 @@ def scan(faster=False):
         wpt_lint_errors = check_wpt_lint_errors()
 
     # collect errors
-    errors = itertools.chain(errors, r_errors, not_found_in_basic_list_errors, wpt_lint_errors)
+    errors = itertools.chain(errors, wpt_lint_errors)
 
     error = None
     for error in errors:
diff --git a/tests/ref/100x100_green.png b/tests/ref/100x100_green.png
deleted file mode 100644
index b23bbba154e..00000000000
--- a/tests/ref/100x100_green.png
+++ /dev/null
diff --git a/tests/ref/2x4.png b/tests/ref/2x4.png
deleted file mode 100644
index 7efc762459b..00000000000
--- a/tests/ref/2x4.png
+++ /dev/null
diff --git a/tests/ref/basic.list b/tests/ref/basic.list
deleted file mode 100644
index 4ee563b6c09..00000000000
--- a/tests/ref/basic.list
+++ /dev/null
@@ -1,8 +0,0 @@
-# This file must be sorted alphabetically.
-# Please run `./mach test-tidy` to check your changes.
-
-# Should be == with expected failure:
-fragment=top != ../html/acid2.html acid2_ref.html
-
-# This file must be sorted alphabetically.
-# Please run `./mach test-tidy` to check your changes.
diff --git a/tests/ref/css/ahem.css b/tests/ref/css/ahem.css
deleted file mode 100644
index 51eede74aaa..00000000000
--- a/tests/ref/css/ahem.css
+++ /dev/null
@@ -1,5 +0,0 @@
-body {
-    font-family: 'ahem';
-    font-size: 100px;
-    line-height: 1;
-}
diff --git a/tests/ref/css/displaynone.css b/tests/ref/css/displaynone.css
deleted file mode 100644
index 525534e8ff4..00000000000
--- a/tests/ref/css/displaynone.css
+++ /dev/null
@@ -1,4 +0,0 @@
-body {
-  display: none;
-}
-
diff --git a/tests/ref/png_rgba_colorspace_a.png b/tests/ref/png_rgba_colorspace_a.png
deleted file mode 100644
index 9b9bd17fe47..00000000000
--- a/tests/ref/png_rgba_colorspace_a.png
+++ /dev/null
diff --git a/tests/ref/reset.css b/tests/ref/reset.css
deleted file mode 100644
index e5156472701..00000000000
--- a/tests/ref/reset.css
+++ /dev/null
@@ -1,48 +0,0 @@
-/* http://meyerweb.com/eric/tools/css/reset/ 
-   v2.0 | 20110126
-   License: none (public domain)
-*/
-
-html, body, div, span, applet, object, iframe,
-h1, h2, h3, h4, h5, h6, p, blockquote, pre,
-a, abbr, acronym, address, big, cite, code,
-del, dfn, em, img, ins, kbd, q, s, samp,
-small, strike, strong, sub, sup, tt, var,
-b, u, i, center,
-dl, dt, dd, ol, ul, li,
-fieldset, form, label, legend,
-table, caption, tbody, tfoot, thead, tr, th, td,
-article, aside, canvas, details, embed, 
-figure, figcaption, footer, header, hgroup, 
-menu, nav, output, ruby, section, summary,
-time, mark, audio, video {
-    margin: 0;
-    padding: 0;
-    border: 0;
-    font-size: 100%;
-    font: inherit;
-    vertical-align: baseline;
-}
-/* HTML5 display-role reset for older browsers */
-article, aside, details, figcaption, figure, 
-footer, header, hgroup, menu, nav, section {
-    display: block;
-}
-body {
-    line-height: 1;
-}
-ol, ul {
-    list-style: none;
-}
-blockquote, q {
-    quotes: none;
-}
-blockquote:before, blockquote:after,
-q:before, q:after {
-    content: '';
-    content: none;
-}
-table {
-    border-collapse: collapse;
-    border-spacing: 0;
-}
diff --git a/tests/ref/rippy.jpg b/tests/ref/rippy.jpg
deleted file mode 100644
index 2a1e0dc9e4c..00000000000
--- a/tests/ref/rippy.jpg
+++ /dev/null
diff --git a/tests/ref/rust-0.png b/tests/ref/rust-0.png
deleted file mode 100644
index 20d93badf5e..00000000000
--- a/tests/ref/rust-0.png
+++ /dev/null
diff --git a/tests/ref/rust.png b/tests/ref/rust.png
deleted file mode 100644
index 68b5ed31e7b..00000000000
--- a/tests/ref/rust.png
+++ /dev/null
diff --git a/tests/ref/rust_logo.png b/tests/ref/rust_logo.png
deleted file mode 100644
index 20d93badf5e..00000000000
--- a/tests/ref/rust_logo.png
+++ /dev/null
diff --git a/tests/ref/test.jpeg b/tests/ref/test.jpeg
deleted file mode 100644
index 3314a53600b..00000000000
--- a/tests/ref/test.jpeg
+++ /dev/null
diff --git a/tests/reftest.rs b/tests/reftest.rs
deleted file mode 100644
index 376c5ac3c04..00000000000
--- a/tests/reftest.rs
+++ /dev/null
@@ -1,395 +0,0 @@
-// Copyright 2013 The Servo Project Developers. See the COPYRIGHT
-// file at the top-level directory of this distribution.
-//
-// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
-// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
-// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
-// option. This file may not be copied, modified, or distributed
-// except according to those terms.
-
-#![feature(fs_walk)]
-#![feature(slice_patterns)]
-#![feature(test)]
-
-#[macro_use] extern crate bitflags;
-extern crate image;
-extern crate test;
-extern crate url;
-extern crate util;
-
-use image::{DynamicImage, GenericImage, ImageFormat, RgbImage};
-use std::env;
-use std::ffi::OsStr;
-use std::fs::{File, walk_dir};
-use std::io::{self, Read, Result, Write};
-use std::path::{Path, PathBuf};
-use std::process;
-use std::process::{Command};
-use std::thread;
-use std::time::Duration;
-use test::run_tests_console;
-use test::{AutoColor, DynTestName, DynTestFn, TestDesc, TestOpts, TestDescAndFn, ShouldPanic};
-use url::Url;
-
-bitflags!(
-    flags RenderMode: u32 {
-        const CPU_RENDERING  = 0x00000001,
-        const GPU_RENDERING  = 0x00000010,
-        const LINUX_TARGET   = 0x00000100,
-        const MACOS_TARGET   = 0x00001000,
-        const ANDROID_TARGET = 0x00010000
-    }
-);
-
-
-fn main() {
-    let args: Vec<String> = env::args().collect();
-    let mut parts = args[1..].split(|e| &**e == "--");
-
-    let harness_args = parts.next().unwrap();  // .split() is never empty
-    let servo_args = parts.next().unwrap_or(&[]);
-
-    let (render_mode_string, base_path, testnames) = match harness_args {
-        [ref render_mode_string, ref base_path, testnames..] =>
-            (render_mode_string, base_path, testnames),
-        _ => panic!("USAGE: cpu|gpu base_path [testname ...]"),
-    };
-
-    let mut render_mode = match &**render_mode_string {
-        "cpu" => CPU_RENDERING,
-        "gpu" => GPU_RENDERING,
-        _ => panic!("First argument must specify cpu or gpu as rendering mode")
-    };
-    if cfg!(target_os = "linux") {
-        render_mode.insert(LINUX_TARGET);
-    }
-    if cfg!(target_os = "macos") {
-        render_mode.insert(MACOS_TARGET);
-    }
-    if cfg!(target_os = "android") {
-        render_mode.insert(ANDROID_TARGET);
-    }
-
-    let mut all_tests = vec!();
-    println!("Scanning {} for manifests\n", base_path);
-
-    for file in walk_dir(base_path).unwrap() {
-        let file = file.unwrap().path();
-        let maybe_extension = file.extension();
-        match maybe_extension {
-            Some(extension) => {
-                if extension == OsStr::new("list") && file.is_file() {
-                    let len = all_tests.len();
-                    let mut tests = parse_lists(&file, testnames, servo_args, render_mode, len);
-                    println!("\t{} [{} tests]", file.display(), tests.len());
-                    all_tests.append(&mut tests);
-                }
-            }
-            _ => {}
-        }
-    }
-
-    let test_opts = TestOpts {
-        filter: None,
-        run_ignored: false,
-        logfile: None,
-        run_tests: true,
-        bench_benchmarks: false,
-        nocapture: false,
-        color: AutoColor,
-    };
-
-    match run(test_opts,
-              all_tests,
-              servo_args.iter().cloned().collect()) {
-        Ok(false) => process::exit(1), // tests failed
-        Err(_) => process::exit(2),    // I/O-related failure
-        _ => (),
-    }
-}
-
-fn run(test_opts: TestOpts, all_tests: Vec<TestDescAndFn>,
-       servo_args: Vec<String>) -> io::Result<bool> {
-    // Verify that we're passing in valid servo arguments. Otherwise, servo
-    // will exit before we've run any tests, and it will appear to us as if
-    // all the tests are failing.
-    let mut command = Command::new(&servo_path());
-    command
-        .args(&servo_args)
-        .arg("-z")
-        .arg("about:blank");
-
-    let mut child = match command.spawn() {
-        Ok(p) => p,
-        Err(e) => panic!("failed to execute process: {}", e),
-    };
-
-    // Wait for the shell to launch or to fail
-    thread::sleep(Duration::from_secs(1));
-    child.kill().unwrap();
-    let output = try!(child.wait_with_output());
-
-    let stderr = String::from_utf8(output.stderr).unwrap();
-
-    if stderr.contains("Unrecognized") {
-        println!("Servo: {}", stderr);
-        return Ok(false);
-    }
-
-    run_tests_console(&test_opts, all_tests)
-}
-
-#[derive(PartialEq)]
-enum ReftestKind {
-    Same,
-    Different,
-}
-
-struct Reftest {
-    name: String,
-    kind: ReftestKind,
-    files: [PathBuf; 2],
-    id: usize,
-    servo_args: Vec<String>,
-    render_mode: RenderMode,
-    is_flaky: bool,
-    prefs: Vec<String>,
-    fragment_identifier: Option<String>,
-    resolution: Option<String>,
-    pixel_ratio: Option<f32>,
-}
-
-struct TestLine<'a> {
-    conditions: &'a str,
-    kind: &'a str,
-    file_left: &'a str,
-    file_right: &'a str,
-}
-
-fn parse_lists(file: &Path,
-               filters: &[String],
-               servo_args: &[String],
-               render_mode: RenderMode,
-               id_offset: usize)
-               -> Vec<TestDescAndFn> {
-    let mut tests = Vec::new();
-    let contents = {
-        let mut f = File::open(file).unwrap();
-        let mut contents = String::new();
-        f.read_to_string(&mut contents).unwrap();
-        contents
-    };
-
-    for line in contents.lines() {
-        // ignore comments or empty lines
-        if line.starts_with("#") || line.is_empty() {
-            continue;
-        }
-
-        let parts: Vec<&str> = line.split(' ').filter(|p| !p.is_empty()).collect();
-
-        let test_line = match parts.len() {
-            3 => TestLine {
-                conditions: "",
-                kind: parts[0],
-                file_left: parts[1],
-                file_right: parts[2],
-            },
-            4 => TestLine {
-                conditions: parts[0],
-                kind: parts[1],
-                file_left: parts[2],
-                file_right: parts[3],
-            },
-            _ => panic!("reftest line: '{}' doesn't match '[CONDITIONS] KIND LEFT RIGHT'", line),
-        };
-
-        let kind = match test_line.kind {
-            "==" => ReftestKind::Same,
-            "!=" => ReftestKind::Different,
-            part => panic!("reftest line: '{}' has invalid kind '{}'", line, part)
-        };
-
-        let base = env::current_dir().unwrap().join(file.parent().unwrap());
-
-        let file_left =  base.join(test_line.file_left);
-        let file_right = base.join(test_line.file_right);
-
-        let conditions_list = test_line.conditions.split(',');
-        let mut flakiness = RenderMode::empty();
-        let mut prefs = vec![];
-        let mut fragment_identifier = None;
-        let mut resolution = None;
-        let mut pixel_ratio = None;
-        for condition in conditions_list {
-            match condition {
-                "flaky_cpu" => flakiness.insert(CPU_RENDERING),
-                "flaky_gpu" => flakiness.insert(GPU_RENDERING),
-                "flaky_linux" => flakiness.insert(LINUX_TARGET),
-                "flaky_macos" => flakiness.insert(MACOS_TARGET),
-                _ => ()
-            }
-            if condition.starts_with("prefs:\"") {
-                if let Some(joined) = condition.split("\"").nth(1) {
-                    prefs.extend(joined.split(",").map(str::to_owned));
-                }
-            }
-            if condition.starts_with("fragment=") {
-                fragment_identifier = Some(condition["fragment=".len()..].to_string());
-            }
-            if condition.starts_with("resolution=") {
-                resolution = Some(condition["resolution=".len() ..].to_string());
-            }
-            if condition.starts_with("device-pixel-ratio=") {
-                pixel_ratio = Some(condition["device-pixel-ratio=".len() ..].to_string()
-                                   .parse().expect("Invalid device-pixel-ratio"));
-            }
-        }
-
-        let reftest = Reftest {
-            name: format!("{} {} {}", test_line.file_left, test_line.kind, test_line.file_right),
-            kind: kind,
-            files: [file_left, file_right],
-            id: id_offset + tests.len(),
-            render_mode: render_mode,
-            servo_args: servo_args.to_vec(),
-            is_flaky: render_mode.intersects(flakiness),
-            prefs: prefs,
-            fragment_identifier: fragment_identifier,
-            resolution: resolution,
-            pixel_ratio: pixel_ratio,
-        };
-
-        if filters.is_empty() || filters.iter().any(|pattern| reftest.name.contains(pattern)) {
-            tests.push(make_test(reftest));
-        }
-    }
-    tests
-}
-
-fn make_test(reftest: Reftest) -> TestDescAndFn {
-    let name = reftest.name.clone();
-    TestDescAndFn {
-        desc: TestDesc {
-            name: DynTestName(name),
-            ignore: false,
-            should_panic: ShouldPanic::No,
-        },
-        testfn: DynTestFn(Box::new(move || {
-            check_reftest(reftest);
-        })),
-    }
-}
-
-fn capture(reftest: &Reftest, side: usize) -> (u32, u32, Vec<u8>) {
-    let png_filename = format!("/tmp/servo-reftest-{:06}-{}.png", reftest.id, side);
-    let mut command = Command::new(&servo_path());
-    command
-        .args(&reftest.servo_args[..])
-        .arg("--user-stylesheet").arg(util::resource_files::resources_dir_path().join("ahem.css"))
-        // Allows pixel perfect rendering of Ahem font and the HTML canvas for reftests.
-        .arg("-Z")
-        .arg("disable-text-aa,disable-canvas-aa")
-        .args(&["-f", "-o"])
-        .arg(&png_filename)
-        .arg(&{
-            let mut url = Url::from_file_path(&*reftest.files[side]).unwrap();
-            url.fragment = reftest.fragment_identifier.clone();
-            url.to_string()
-        });
-    // CPU rendering is the default
-    if reftest.render_mode.contains(CPU_RENDERING) {
-        command.arg("-c");
-    }
-    if reftest.render_mode.contains(GPU_RENDERING) {
-        command.arg("-g");
-    }
-    for pref in &reftest.prefs {
-        command.arg("--pref");
-        command.arg(pref);
-    }
-    if let Some(ref resolution) = reftest.resolution {
-        command.arg("--resolution");
-        command.arg(resolution);
-    }
-    if let Some(pixel_ratio) = reftest.pixel_ratio {
-        command.arg("--device-pixel-ratio");
-        command.arg(pixel_ratio.to_string());
-    }
-    let (exit_status, stderr, stdout) = match command.output() {
-        Ok(output) => (output.status, output.stderr, output.stdout),
-        Err(e) => panic!("failed to execute process: {}", e),
-    };
-
-    if !stdout.is_empty() {
-        let stdout_filename = format!("/tmp/servo-reftest-{:06}-{}-stdout.txt", reftest.id, side);
-        let mut stdout_file = File::create(stdout_filename).unwrap();
-        stdout_file.write_all(&stdout[..]).unwrap();
-    }
-
-    if !stderr.is_empty() {
-        let stderr_filename = format!("/tmp/servo-reftest-{:06}-{}-stderr.txt", reftest.id, side);
-        let mut stderr_file = File::create(stderr_filename).unwrap();
-        stderr_file.write_all(&stderr[..]).unwrap();
-    }
-
-    assert!(exit_status.success());
-
-    let image = match image::open(&png_filename) {
-        Ok(DynamicImage::ImageRgb8(image)) => image,
-        Ok(image) => image.to_rgb(),
-        _ => panic!(),
-    };
-    (image.width(), image.height(), image.into_raw())
-}
-
-fn servo_path() -> PathBuf {
-    let current_exe = env::current_exe().ok().expect("Could not locate current executable");
-    current_exe.parent().unwrap().join("servo")
-}
-
-fn check_reftest(reftest: Reftest) {
-    let (left_width, left_height, left_bytes) = capture(&reftest, 0);
-    let (right_width, right_height, right_bytes) = capture(&reftest, 1);
-
-    // TODO(gw): This is a workaround for https://github.com/servo/servo/issues/7730
-    if !reftest.is_flaky {
-        assert_eq!(left_width, right_width);
-        assert_eq!(left_height, right_height);
-
-        let left_all_white = left_bytes.iter().all(|&p| p == 255);
-        let right_all_white = right_bytes.iter().all(|&p| p == 255);
-
-        if left_all_white && right_all_white {
-            panic!("Both renderings are empty")
-        }
-    }
-
-    let pixels = left_bytes.iter().zip(right_bytes.iter()).map(|(&a, &b)| {
-        if a == b {
-            // White for correct
-            0xFF
-        } else {
-            // "1100" in the RGBA channel with an error for an incorrect value
-            // This results in some number of C0 and FFs, which is much more
-            // readable (and distinguishable) than the previous difference-wise
-            // scaling but does not require reconstructing the actual RGBA pixel.
-            0xC0
-        }
-    }).collect::<Vec<u8>>();
-
-    if pixels.iter().any(|&a| a < 255) {
-        let output = format!("/tmp/servo-reftest-{:06}-diff.png", reftest.id);
-        let mut file = File::create(&output).unwrap();
-        let img_buf = RgbImage::from_raw(left_width, left_height, pixels).expect("foo");
-        DynamicImage::ImageRgb8(img_buf).save(&mut file, ImageFormat::PNG).unwrap();
-
-        match (reftest.kind, reftest.is_flaky) {
-            (ReftestKind::Same, true) => println!("flaky test - rendering difference: {}", output),
-            (ReftestKind::Same, false) => panic!("rendering difference: {}", output),
-            (ReftestKind::Different, _) => {}   // Result was different and that's what was expected
-        }
-    } else {
-        assert!(reftest.is_flaky || reftest.kind == ReftestKind::Same);
-    }
-}
diff --git a/tests/wpt/mozilla/meta/MANIFEST.json b/tests/wpt/mozilla/meta/MANIFEST.json
index d6fc30b6a8f..44620f9b226 100644
--- a/tests/wpt/mozilla/meta/MANIFEST.json
+++ b/tests/wpt/mozilla/meta/MANIFEST.json
@@ -151,6 +151,19 @@
             "url": "/_mozilla/css/acid1_a.html"
           }
         ],
+        "css/acid2-wrapper.html": [
+          {
+            "path": "css/acid2-wrapper.html",
+            "references": [
+              [
+                "/_mozilla/css/acid2_ref_broken.html",
+                "=="
+              ]
+            ],
+            "timeout": "long",
+            "url": "/_mozilla/css/acid2-wrapper.html"
+          }
+        ],
         "css/acid2_noscroll.html": [
           {
             "path": "css/acid2_noscroll.html",
@@ -163,6 +176,18 @@
             "url": "/_mozilla/css/acid2_noscroll.html"
           }
         ],
+        "css/acid2_ref.html": [
+          {
+            "path": "css/acid2_ref.html",
+            "references": [
+              [
+                "/_mozilla/css/acid2_ref_broken.html",
+                "=="
+              ]
+            ],
+            "url": "/_mozilla/css/acid2_ref.html"
+          }
+        ],
         "css/after_block_iteration.html": [
           {
             "path": "css/after_block_iteration.html",
@@ -6194,6 +6219,19 @@
           "url": "/_mozilla/css/acid1_a.html"
         }
       ],
+      "css/acid2-wrapper.html": [
+        {
+          "path": "css/acid2-wrapper.html",
+          "references": [
+            [
+              "/_mozilla/css/acid2_ref_broken.html",
+              "=="
+            ]
+          ],
+          "timeout": "long",
+          "url": "/_mozilla/css/acid2-wrapper.html"
+        }
+      ],
       "css/acid2_noscroll.html": [
         {
           "path": "css/acid2_noscroll.html",
@@ -6206,6 +6244,18 @@
           "url": "/_mozilla/css/acid2_noscroll.html"
         }
       ],
+      "css/acid2_ref.html": [
+        {
+          "path": "css/acid2_ref.html",
+          "references": [
+            [
+              "/_mozilla/css/acid2_ref_broken.html",
+              "=="
+            ]
+          ],
+          "url": "/_mozilla/css/acid2_ref.html"
+        }
+      ],
       "css/after_block_iteration.html": [
         {
           "path": "css/after_block_iteration.html",
diff --git a/tests/wpt/mozilla/meta/css/acid2-wrapper.html.ini b/tests/wpt/mozilla/meta/css/acid2-wrapper.html.ini
new file mode 100644
index 00000000000..f2657877a44
--- /dev/null
+++ b/tests/wpt/mozilla/meta/css/acid2-wrapper.html.ini
@@ -0,0 +1,3 @@
+[acid2-wrapper.html]
+  type: reftest
+  disabled: https://github.com/servo/servo/issues/9310
diff --git a/tests/wpt/mozilla/meta/css/acid2_ref.html.ini b/tests/wpt/mozilla/meta/css/acid2_ref.html.ini
new file mode 100644
index 00000000000..55dd5ca27f3
--- /dev/null
+++ b/tests/wpt/mozilla/meta/css/acid2_ref.html.ini
@@ -0,0 +1,3 @@
+[acid2_ref.html]
+  type: reftest
+  expected: FAIL
diff --git a/tests/wpt/mozilla/tests/css/acid2-wrapper.html b/tests/wpt/mozilla/tests/css/acid2-wrapper.html
new file mode 100644
index 00000000000..d1907a92b64
--- /dev/null
+++ b/tests/wpt/mozilla/tests/css/acid2-wrapper.html
@@ -0,0 +1,15 @@
+<!doctype html>
+<html class=reftest-wait>
+<meta name=timeout content=long>
+<link rel=match href=acid2_ref_broken.html>
+<style>
+body {
+  margin: 0;
+}
+iframe {
+  width: 100vw;
+  height: 100vh;
+  border: 0;
+}
+</style>
+<iframe src="acid2.html#top" onload="document.documentElement.className = ''"></iframe>
diff --git a/tests/wpt/mozilla/tests/css/acid2.html b/tests/wpt/mozilla/tests/css/acid2.html
new file mode 100755
index 00000000000..2f700b14e71
--- /dev/null
+++ b/tests/wpt/mozilla/tests/css/acid2.html
@@ -0,0 +1,150 @@
+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
+<html>
+ <head>
+  <title>The Second Acid Test</title>
+  <style type="text/css">
+   /* section numbers refer to CSS2.1 */
+
+   /* page setup */
+   html { font: 12px sans-serif; margin: 0; padding: 0; overflow: hidden; /* hides scrollbars on viewport, see 11.1.1:3 */ background: white; color: red; }
+   body { margin: 0; padding: 0; }
+
+   /* introduction message */
+   .intro { font: 2em sans-serif; margin: 3.5em 2em; padding: 0.5em; border: solid thin; background: white; color: black; position: relative; z-index: 2; /* should cover the black and red bars that are fixed-positioned */ }
+   .intro * { font: inherit; margin: 0; padding: 0; }
+   .intro h1 { font-size: 1em; font-weight: bolder; margin: 0; padding: 0; }
+   .intro :link { color: blue; }
+   .intro :visited { color: purple; }
+
+   /* picture setup */
+   #top { margin: 100em 3em 0; padding: 2em 0 0 .5em; text-align: left; font: 2em/24px sans-serif; color: navy; white-space: pre; } /* "Hello World!" text */
+   .picture { position: relative; border: 1em solid transparent; margin: 0 0 100em 3em; } /* containing block for face */
+   .picture { background: red; } /* overridden by preferred stylesheet below */
+
+   /* top line of face (scalp): fixed positioning and min/max height/width */
+   .picture p { position: fixed; margin: 0; padding: 0; border: 0; top: 9em; left: 11em; width: 140%; max-width: 4em; height: 8px; min-height: 1em; max-height: 2mm; /* min-height overrides max-height, see 10.7 */ background: black; border-bottom: 0.5em yellow solid; }
+
+   /* bits that shouldn't be part of the top line (and shouldn't be visible at all): HTML parsing, "+" combinator, stacking order */
+   .picture p.bad { border-bottom: red solid; /* shouldn't matter, because the "p + table + p" rule below should match it too, thus hiding it */ }
+   .picture p + p { background: maroon; z-index: 1; } /* shouldn't match anything */
+   .picture p + table + p { margin-top: 3em; /* should end up under the absolutely positioned table below, and thus not be visible */ }
+
+   /* second line of face: attribute selectors, float positioning */
+   [class~=one].first.one { position: absolute; top: 0; margin: 36px 0 0 60px; padding: 0; border: black 2em; border-style: none solid; /* shrink wraps around float */ }
+   [class~=one][class~=first] [class=second\ two][class="second two"] { float: right; width: 48px; height: 12px; background: yellow; margin: 0; padding: 0; } /* only content of abs pos block */
+
+   /* third line of face: width and overflow */
+   .forehead { margin: 4em; width: 8em; border-left: solid black 1em; border-right: solid black 1em; background: red url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAIAAACQd1PeAAAADElEQVR42mP4%2F58BAAT%2FAf9jgNErAAAAAElFTkSuQmCC); /* that's a 1x1 yellow pixel PNG */ }
+   .forehead * { width: 12em; line-height: 1em; }
+
+   /* class selectors headache */
+   .two.error.two { background: maroon; } /* shouldn't match */
+   .forehead.error.forehead { background: red; } /* shouldn't match */
+   [class=second two] { background: red; } /* this should be ignored (invalid selector -- grammar says it only accepts IDENTs or STRINGs) */
+
+   /* fourth and fifth lines of face, with eyes: paint order test (see appendix E) and fixed backgrounds */
+   /* the two images are identical: 2-by-2 squares with the top left
+      and bottom right pixels set to yellow and the other two set to
+      transparent. Since they are offset by one pixel from each other,
+      the second one paints exactly over the transparent parts of the
+      first one, thus creating a solid yellow block. */
+   .eyes { position: absolute; top: 5em; left: 3em; margin: 0; padding: 0; background: red; }
+   #eyes-a { height: 0; line-height: 2em; text-align: right; } /* contents should paint top-most because they're inline */
+   #eyes-a object { display: inline; vertical-align: bottom; }
+   #eyes-a object[type] { width: 7.5em; height: 2.5em; } /* should have no effect since that object should fallback to being inline (height/width don't apply to inlines) */
+   #eyes-a object object object { border-right: solid 1em black; padding: 0 12px 0 11px; background: url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAIAAAACCAIAAAD91JpzAAAABnRSTlMAAAAAAABupgeRAAAABmJLR0QA%2FwD%2FAP%2BgvaeTAAAAEUlEQVR42mP4%2F58BCv7%2FZwAAHfAD%2FabwPj4AAAAASUVORK5CYII%3D) fixed 1px 0; }
+   #eyes-b { float: left; width: 10em; height: 2em; background: fixed url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAIAAAACCAIAAAD91JpzAAAABnRSTlMAAAAAAABupgeRAAAABmJLR0QA%2FwD%2FAP%2BgvaeTAAAAEUlEQVR42mP4%2F58BCv7%2FZwAAHfAD%2FabwPj4AAAAASUVORK5CYII%3D); border-left: solid 1em black; border-right: solid 1em red; } /* should paint in the middle layer because it is a float */
+   #eyes-c { display: block; background: red; border-left: 2em solid yellow; width: 10em; height: 2em; } /* should paint bottom most because it is a block */
+
+   /* lines six to nine, with nose: auto margins */
+   .nose { float: left; margin: -2em 2em -1em; border: solid 1em black; border-top: 0; min-height: 80%; height: 60%; max-height: 3em; /* percentages become auto (see 10.5 and 10.7) and intrinsic height is more than 3em, so 3em wins */ padding: 0; width: 12em; }
+   .nose > div { padding: 1em 1em 3em; height: 0; background: yellow; }
+   .nose div div { width: 2em; height: 2em; background: red; margin: auto; }
+   .nose :hover div { border-color: blue; }
+   .nose div:hover :before { border-bottom-color: inherit; }
+   .nose div:hover :after { border-top-color: inherit; }
+   .nose div div:before { display: block; border-style: none solid solid; border-color: red yellow black yellow; border-width: 1em; content: ''; height: 0; }
+   .nose div    :after { display: block; border-style: solid solid none; border-color: black yellow red yellow; border-width: 1em; content: ''; height: 0; }
+
+   /* between lines nine and ten: margin collapsing with 'float' and 'clear' */
+   .empty { margin: 6.25em; height: 10%; /* computes to auto which makes it empty per 8.3.1:7 (own margins) */ }
+   .empty div { margin: 0 2em -6em 4em; }
+   .smile { margin: 5em 3em; clear: both; /* clearance is negative (see 8.3.1 and 9.5.1) */ }
+
+   /* line ten and eleven: containing block for abs pos */
+   .smile div { margin-top: 0.25em; background: black; width: 12em; height: 2em; position: relative; bottom: -1em; }
+   .smile div div { position: absolute; top: 0; right: 1em; width: auto; height: 0; margin: 0; border: yellow solid 1em; }
+
+   /* smile (over lines ten and eleven): backgrounds behind borders, inheritance of 'float', nested floats, negative heights */
+   .smile div div span { display: inline; margin: -1em 0 0 0; border: solid 1em transparent; border-style: none solid; float: right; background: black; height: 1em; }
+   .smile div div span em { float: inherit; border-top: solid yellow 1em; border-bottom: solid black 1em; } /* zero-height block; width comes from (zero-height) child. */
+   .smile div div span em strong { width: 6em; display: block; margin-bottom: -1em; /* should have no effect, since parent has top&bottom borders, so this margin doesn't collapse */ }
+
+   /* line twelve: line-height */
+   .chin { margin: -4em 4em 0; width: 8em; line-height: 1em; border-left: solid 1em black; border-right: solid 1em black; background: yellow url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAEAAAABACAIAAAFSDNYfAAAAaklEQVR42u3XQQrAIAwAQeP%2F%2F6wf8CJBJTK9lnQ7FpHGaOurt1I34nfH9pMMZAZ8BwMGEvvh%2BBsJCAgICLwIOA8EBAQEBAQEBAQEBK79H5RfIQAAAAAAAAAAAAAAAAAAAAAAAAAAAID%2FABMSqAfj%2FsLmvAAAAABJRU5ErkJggg%3D%3D) /* 64x64 red square */ no-repeat fixed /* shouldn't be visible unless the smiley is moved to the top left of the viewport */; }
+   .chin div { display: inline; font: 2px/4px serif; }
+
+   /* line thirteen: cascade and selector tests */
+   .parser-container div { color: maroon; border: solid; color: orange; } /* setup */
+   div.parser-container * { border-color: black; /* overrides (implied) border-color on previous line */ } /* setup */
+   * div.parser { border-width: 0 2em; /* overrides (implied) declarations on earlier line */ } /* setup */
+
+   /* line thirteen continued: parser tests */
+   .parser { /* comment parsing test -- comment ends before the end of this line, the backslash should have no effect: \*/ }
+   .parser { margin: 0 5em 1em; padding: 0 1em; width: 2em; height: 1em; error: \}; background: yellow; } /* setup with parsing test */
+   * html .parser {  background: gray; }
+   \.parser { padding: 2em; }
+   .parser { m\argin: 2em; };
+   .parser { height: 3em; }
+   .parser { width: 200; }
+   .parser { border: 5em solid red ! error; }
+   .parser { background: red pink; }
+
+   /* line fourteen (last line of face): table */
+   ul { display: table; padding: 0; margin: -1em 7em 0; background: red; }
+   ul li { padding: 0; margin: 0; }
+   ul li.first-part { display: table-cell; height: 1em; width: 1em; background: black; }
+   ul li.second-part { display: table; height: 1em; width: 1em; background: black; } /* anonymous table cell wraps around this */
+   ul li.third-part { display: table-cell; height: 0.5em; /* gets stretched to fit row */ width: 1em; background: black; }
+   ul li.fourth-part { list-style: none; height: 1em; width: 1em; background: black; } /* anonymous table cell wraps around this */
+
+   /* bits that shouldn't appear: inline alignment in cells */
+   .image-height-test { height: 10px; overflow: hidden; font: 20em serif; } /* only the area between the top of the line box and the top of the image should be visible */
+   table { margin: 0; border-spacing: 0; }
+   td { padding: 0; }
+
+  </style>
+  <link rel="appendix stylesheet" href="data:text/css,.picture%20%7B%20background%3A%20none%3B%20%7D"> <!-- this stylesheet should be applied by default -->
+ </head>
+ <body>
+  <div class="intro">
+   <h1>Standards compliant?</h1>
+   <p><a href="#top">Take The Acid2 Test</a> and compare it to <a
+   href="reference.html">the reference rendering</a>.</p>
+  </div>
+  <h2 id="top">Hello World!</h2>
+  <div class="picture">
+   <p><table><tr><td></table><p class="bad"> <!-- <table> closes <p> per the HTML4 DTD -->
+   <blockquote class="first one"><address class="second two"></address></blockquote>
+   <div class="forehead"><div>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</div></div>
+   <div class="eyes"><div id="eyes-a"><object data="data:application/x-unknown,ERROR"><object data="http://www.damowmow.com/404/" type="text/html"><object data="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAGAAAAAYCAYAAAFy7sgCAAAGsUlEQVRo3u2ZbWwcZxHHf3s%2B7LNbO3ZjXBtowprGODRX0qpNQCjmJKuVKhMl1P2AkCwhFOIKkCBSm9IXavGFKAixIAECwkmWo5MrhRI3Ub40IEwQgp6aIDg3Cd6eEqyIHEteah%2B1E69vhw%2BZtTaX8704ZzkKjHS6271nZ56ZZ%2BY%2F%2F%2BdZKF%2FCwYshx3EkkggLsD1v4FQkEZZYLCbAKyG9%2Ba9EIsG6hnUAf8x74K3aUC3j4%2BM54HcsR2oAIomwZOezkv%2FnSHpYNh%2BNCmAE7xv94zvFdd1bHsjMZmQkPSxAJP%2B%2FfuBLwK54PC7JZFKAVJmzXLBt2w%2FMvcDLwIb8QS8CeJ4nkURYIomw7J%2FYJ8BvSiiXptGGxWds2%2Fa9%2Bnaxh%2BYAD%2Bgt04NDgABTpQY2cvvSFLzw86gWeBVwC8SzlOSv2YeBPfmDBoBHgKmR9LBEEmHZfDTqGykqfkUE0nA78BzQGfSgUeP3wNeTXwXg7MwZDhw4UHL6ra2ti79%2FOvljgG8AZ4H64Lhm4MvAocxsRppGG%2FxcXihlwLIs6R%2FfKV2HO%2F26uA94pdDYUKUZUU7W1RQYXA98Gnhaf5%2FXWX0HeAHYoQonqa4sZSOsSWMCWeC9Yko%2BCQwBe4E6oNc0Tc91XTl1%2BaTsn9gnI%2Blhyc5nZWxsrBIkKSbl2tiic3tW53YDEwOKaoFBrcOfqKee53lG9xsPMjV784r%2F4lO%2FpPvyJ9iyZcuvFSaXK5XYeAZ4CDgGvB3MS4B54LQuWYPeuy4iRFsevsXqpuYoqVQKIH2bK1CuDQNo11o4XUzh%2FcDWYIe1LEtyuZx4niee54njOGKapgfsqlL%2Bl2OjEXg8nxrc1dJ0h3hbtL%2BGCtz7KPBF4CuBe9uB15VafE8hr9qylI3HgG8C2%2FK7VyHZoJj7MrBRm30qFotJMpkU27YlHo%2F7Ha5a%2BV%2FKRkSJ4KuKRLVLKapTjB1SzAVIjY2NSXY%2BKyPpYdk%2FsU9OXT4pruv6BdZbBQfKsVGnvWlIe1VB6VQO8JxC1vZYLCbZ%2BaxsPhpdZDyRRFhG0sPiOE6ldKBg2lRg4xF1YCDIIIKN7DGgD3gH%2BBXwejKZfPrs2tPs%2FvPN2bKuYR1nd7xLKBSSJeqoXKnERjPwNWAG%2BLn2rZuM%2B4Tpml6vaWlp4eLcxVusZq5lCgVgOVKJjRqdX86ffL4D5wIoZACnTpw4wRMdT96i%2FImOJxERAs4uVyqxUacF%2FPdiCj%2BjdRBRGFtwXVdG0sPSdbhTmkYbpH98p2RmM2JZlig1vl0GWo4NQ%2Fn%2Bs5pKRXfwjweaxy7TND3HcRZbfC6X8xVPVQlGy7WxVWlO5XRXFXm6EZmrQuSXYyPE3SiVoEhE6Wyr0u2rumO6zv%2B21AFdQAswC1wCMuUCXCmyWQus103Qg8qlDO0lxwOb%2Fl4FiK3AB3VS%2FuKKLtK%2FgbeAnwG%2FvUODuRw%2FFrR0H1UC75fwu8oJ%2FhFsW5VIG%2FBUgEIN6Y65O4AHu4Ap0zQ9y7LEcZyb9lRBUHQcRyzL8unZVBW5bFWAvAp%2BhDQ2g4F47dUYtlU6obXA54DnVdFLekjUGGifh4AFy7LEdV3xj3X9I66m0QZpGm2QrsOd0j%2B%2BU0bSw5KZzYjrun6HWlAd961i4FfCj0aN1Usau%2Bc1lmuXPFwvAEumUut7tQQvAb%2FXb%2FT0bCAej9cODg7yt%2Bm%2F8q2%2F7OUHZ76PnZ1k2p0mJzlykmPancbOTnL0whHs7CQfb%2B5mx2d3sH79%2BtCRI0c6FeaOr9ICrIQfLvA%2B8BGNXxi4R6HrisJVUWrxAVW2oMFf0Aczim8o3kV6enowDIPjF9%2Fk%2BMU3S3rrjzMMg56eHr%2BxP7qKFbASfojG6kpeDGs1tiW53RxwWT%2Bin5q8w4xpQK5evQpAR30H7ZH2khNvj7TTUd8BgD4rqmu1ZKX8qNeY%2BfHz4zlXDgT5E8tpCTUq7XSBC4Euv8227TV9fX1E73%2BYtvo27BmbS9cvFVTY3bSRFza9yOcf6Gfmygy7d%2B%2Fm%2FPnzF4DvrsBLhnJlJfwIKXxv1PheAE4qK6p4H9AGbNKTuhngBPBPXYRe4IemaT5kWZbR19fHNbmGnZ1k4r3U4glDR30Hm5qjbGjsImJEOHbsGHv27JFz5869o0eFq01Jq%2BmHAXwI6FFKagMTgHM7GzFDS%2BoeLSMv7zjzC9x4Y7gxFovVDAwMEI1GaWlpWSzRVCrFwYMH%2FXfxZ4AfAa8B%2F7lDaGg1%2FQgp43lfK0yqtRMuJa3ceKe5DfgYsCYAZ2ngD8CfAkzqTpW7xY%2F%2FSznyX%2FVeUb2kVmX4AAAAAElFTkSuQmCC">ERROR</object></object></object></div><div id="eyes-b"></div><div id="eyes-c"></div></div> <!-- that's a PNG with 8bit alpha containing two eyes -->
+   <div class="nose"><div><div></div></div></div>
+   <div class="empty"><div></div></div>
+   <div class="smile"><div><div><span><em><strong></strong></em></span></div></div></div>
+   <div class="chin"><div>&nbsp;</div></div>
+   <div class="parser-container"><div class="parser"><!-- ->ERROR<!- --></div></div> <!-- two dashes is what delimits a comment, so the text "->ERROR<!-" earlier on this line is actually part of a comment -->
+   <ul>
+    <li class="first-part"></li>
+    <li class="second-part"></li>
+    <li class="third-part"></li>
+    <li class="fourth-part"></li>
+   </ul>
+   <div class="image-height-test"><table><tr><td><img src="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAEAAAABACAIAAAFSDNYfAAAAaklEQVR42u3XQQrAIAwAQeP%2F%2F6wf8CJBJTK9lnQ7FpHGaOurt1I34nfH9pMMZAZ8BwMGEvvh%2BBsJCAgICLwIOA8EBAQEBAQEBAQEBK79H5RfIQAAAAAAAAAAAAAAAAAAAAAAAAAAAID%2FABMSqAfj%2FsLmvAAAAABJRU5ErkJggg%3D%3D" alt=""></td></tr></table></div>
+  </div>
+  <script>
+//  window.scroll(0, 2684);
+//  setInterval(() => { console.log(window.scrollY);   window.scroll(0, 2684);
+//}, 10); 
+  </script>
+ </body>
+</html>
diff --git a/tests/ref/acid2_ref.html b/tests/wpt/mozilla/tests/css/acid2_ref.html
index a6cc0c01b28..d0b4e28ec3e 100644
--- a/tests/ref/acid2_ref.html
+++ b/tests/wpt/mozilla/tests/css/acid2_ref.html
@@ -2,6 +2,7 @@
 <html>
  <head>
   <title>The Second Acid Test (Reference Rendering)</title>
+  <link rel=match href=acid2_ref_broken.html>
   <style type="text/css">
    html { margin: 0; padding: 0; border: 0; overflow: hidden; background: white; }
    body { margin: 0; padding: 0; border: 0; }
diff --git a/tests/ref/acid2_ref.png b/tests/wpt/mozilla/tests/css/acid2_ref.png
index 7aee7609d6a..7aee7609d6a 100644
--- a/tests/ref/acid2_ref.png
+++ b/tests/wpt/mozilla/tests/css/acid2_ref.png