diff --git a/tests/hs-run-filtered.js b/tests/hs-run-filtered.js
index 8a1406a0..bbcb7f06 100755
--- a/tests/hs-run-filtered.js
+++ b/tests/hs-run-filtered.js
@@ -569,9 +569,28 @@ const _fetchRoutes = {
   '/number': { status: 200, body: '1.2' },
   '/users/Joe': { status: 200, body: 'Joe', json: '{"name":"Joe"}' },
 };
+// Per-test fetch overrides keyed by test name; takes priority over _fetchRoutes.
+const _fetchScripts = {
+  "as response does not throw on 404":
+      { "/test": { status: 404, body: "not found" } },
+  "do not throw passes through 404 response":
+      { "/test": { status: 404, body: "the body" } },
+  "don't throw passes through 404 response":
+      { "/test": { status: 404, body: "the body" } },
+  "throws on non-2xx response by default":
+      { "/test": { status: 404, body: "not found" } },
+  "Response can be converted to JSON via as JSON":
+      { "/test": { status: 200, body: '{"name":"Joe"}', json: '{"name":"Joe"}',
+                   contentType: "application/json" } },
+  "can catch an error that occurs when using fetch":
+      { "/test": { networkError: true } },
+  "triggers an event just before fetching":
+      { "/test": { status: 200, body: "yay", contentType: "text/html" } },
+};
 function _mockFetch(url) {
-  const route = _fetchRoutes[url] || _fetchRoutes['/test'];
-  return { ok: route.status < 400, status: route.status || 200, url: url || '/test',
+  const scriptRoutes = _fetchScripts[globalThis.__currentHsTestName];
+  const route = (scriptRoutes && scriptRoutes[url]) || _fetchRoutes[url] || _fetchRoutes['/test'];
+  return { ok: (route.status||200) < 400, status: route.status || 200, url: url || '/test',
            _body: route.body || '', _json: route.json || route.body || '', _html: route.html || route.body || '' };
 }
 globalThis._driveAsync=function driveAsync(r,d){d=d||0;if(d>500||!r||!r.suspended)return;if(_testDeadline && Date.now()>_testDeadline)throw new Error('TIMEOUT: wall clock exceeded');const req=r.request;const items=req&&(req.items||req);const op=items&&items[0];const opName=typeof op==='string'?op:(op&&op.name)||String(op);
@@ -580,8 +599,10 @@ globalThis._driveAsync=function driveAsync(r,d){d=d||0;if(d>500||!r||!r.suspende
   else if(opName==='io-fetch'){
     const url=typeof items[1]==='string'?items[1]:'/test';
     const fmt=typeof items[2]==='string'?items[2]:'text';
-    const route=_fetchRoutes[url]||_fetchRoutes['/test'];
-    if(fmt==='json'){try{doResume(JSON.parse(route.json||route.body||'{}'));}catch(e){doResume(null);}}
+    const scriptRoutes=_fetchScripts[globalThis.__currentHsTestName];
+    const route=(scriptRoutes&&scriptRoutes[url])||_fetchRoutes[url]||_fetchRoutes['/test'];
+    if(route&&route.networkError){doResume({_network_error:true,message:'aborted'});}
+    else if(fmt==='json'){try{doResume(JSON.parse(route.json||route.body||'{}'));}catch(e){doResume(null);}}
     else if(fmt==='html'){const frag=new El('fragment');frag.nodeType=11;frag.innerHTML=route.html||route.body||'';frag.textContent=frag.innerHTML.replace(/<[^>]*>/g,'');doResume(frag);}
     else if(fmt==='response')doResume({ok:(route.status||200)<400,status:route.status||200,url});
     else if(fmt.toLowerCase()==='number')doResume(parseFloat(route.number||route.body||'0'));