Improve render lifecycle, geometry, and PDF parity

crates/obscura/tests/image_shim.rs

@@ -8,9 +8,15 @@ use std::io::{Read, Write};
 
 use obscura::Browser;
 
-/// Minimal HTTP/1.1 server returning HTML that wraps document.createElement to
-/// plant a non-configurable `src` on every <img>, then calls `new Image()`.
+/// Minimal HTTP/1.1 server returning the test page and a valid 1x1 PNG.
 fn spawn_server(html: &'static str) -> String {
+    const PIXEL_PNG: &[u8] = &[
+        0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a, 0x00, 0x00, 0x00, 0x0d, 0x49, 0x48,
+        0x44, 0x52, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x01, 0x08, 0x06, 0x00, 0x00,
+        0x00, 0x1f, 0x15, 0xc4, 0x89, 0x00, 0x00, 0x00, 0x0d, 0x49, 0x44, 0x41, 0x54, 0x78,
+        0xda, 0x63, 0xfc, 0xcf, 0xc0, 0x50, 0x0f, 0x00, 0x05, 0x83, 0x02, 0x7f, 0x94, 0xff,
+        0x2f, 0x59, 0x00, 0x00, 0x00, 0x00, 0x49, 0x45, 0x4e, 0x44, 0xae, 0x42, 0x60, 0x82,
+    ];
     let listener = std::net::TcpListener::bind("127.0.0.1:0").unwrap();
     let addr = listener.local_addr().unwrap();
     std::thread::spawn(move || {
@@ -20,13 +26,19 @@ fn spawn_server(html: &'static str) -> String {
                 Err(_) => continue,
             };
             let mut buf = [0u8; 2048];
-            let _ = s.read(&mut buf);
-            let resp = format!(
-                "HTTP/1.1 200 OK\r\nContent-Type: text/html\r\nContent-Length: {}\r\nConnection: close\r\n\r\n{}",
-                html.len(),
-                html
+            let read = s.read(&mut buf).unwrap_or(0);
+            let is_pixel = buf[..read].starts_with(b"GET /pixel.png ");
+            let (content_type, body) = if is_pixel {
+                ("image/png", PIXEL_PNG)
+            } else {
+                ("text/html", html.as_bytes())
+            };
+            let headers = format!(
+                "HTTP/1.1 200 OK\r\nContent-Type: {content_type}\r\nContent-Length: {}\r\nConnection: close\r\n\r\n",
+                body.len()
             );
-            let _ = s.write_all(resp.as_bytes());
+            let _ = s.write_all(headers.as_bytes());
+            let _ = s.write_all(body);
             let _ = s.shutdown(std::net::Shutdown::Both);
         }
     });
@@ -100,3 +112,39 @@ async fn new_image_still_emulates_load_when_src_is_configurable() {
         "load emulation regressed for the normal (configurable src) path"
     );
 }
+
+#[tokio::test]
+async fn invalid_image_bytes_emit_error_like_chromium() {
+    std::env::set_var("OBSCURA_ALLOW_PRIVATE_NETWORK", "1");
+    let base = spawn_server(
+        r#"<!doctype html><html><body><div id="r">waiting</div>
+<script>
+  var img = new Image();
+  img.onerror = function () {
+    document.getElementById('r').textContent =
+      'error complete=' + img.complete +
+      ' natural=' + img.naturalWidth + 'x' + img.naturalHeight;
+  };
+  img.src = '/broken.png';
+</script>
+</body></html>"#,
+    );
+
+    let browser = Browser::new().unwrap();
+    let mut page = browser.new_page().await.unwrap();
+    page.goto(&base).await.unwrap();
+    for _ in 0..10 {
+        page.settle(500).await;
+        let text = page.evaluate("document.getElementById('r').textContent");
+        if text.as_str().unwrap_or("").starts_with("error") {
+            break;
+        }
+    }
+
+    let text = page.evaluate("document.getElementById('r').textContent");
+    assert_eq!(
+        text.as_str().unwrap_or(""),
+        "error complete=true natural=0x0",
+        "invalid image bytes must fail instead of being treated as a decoded image"
+    );
+}