diff --git a/test/web-platform-tests/run-single-wpt.js b/test/web-platform-tests/run-single-wpt.js
index 3c8f002b3a..68f949d6d6 100644
--- a/test/web-platform-tests/run-single-wpt.js
+++ b/test/web-platform-tests/run-single-wpt.js
@@ -1,95 +1,20 @@
 "use strict";
-/* eslint-disable no-console, no-process-exit, global-require */
+/* eslint-disable no-console */
 const fs = require("fs");
 const path = require("path");
-const dns = require("dns");
-const childProcess = require("child_process");
-const { EventEmitter } = require("events");
-const q = require("q");
 const { specify } = require("mocha-sugar-free");
 const { inBrowserContext, nodeResolverPromise } = require("../util.js");
-const requestHead = require("request-promise-native").head;
 const jsdom = require("../../lib/old-api.js");
 
-const wptDir = path.resolve(__dirname, "tests");
-
-const configPaths = {
-  default: path.resolve(__dirname, "wpt-config.json"),
-  toUpstream: path.resolve(__dirname, "tuwpt-config.json")
-};
-
-const configs = {
-  default: require(configPaths.default),
-  toUpstream: require(configPaths.toUpstream)
-};
-
 const globalPool = { maxSockets: 6 };
 
-module.exports = ({ toUpstream = false } = {}) => {
+module.exports = urlPrefixFactory => {
   if (inBrowserContext()) {
     return () => {
       // TODO: browser support for running WPT
     };
   }
 
-  const configType = toUpstream ? "toUpstream" : "default";
-  const configPath = configPaths[configType];
-  const config = configs[configType];
-
-  const server = new EventEmitter();
-
-  let serverHasStarted;
-  server.started = new Promise(resolve => {
-    serverHasStarted = resolve;
-  });
-  server.isStarted = false;
-
-  let urlPrefix = `http://${config.host}:${config.ports.http[0]}/`;
-
-  dns.lookup("web-platform.test", err => {
-    if (err) {
-      console.warn();
-      console.warn("Host entries not present for web platform tests.");
-      console.warn("See https://github.com/w3c/web-platform-tests#running-the-tests");
-
-      if (!toUpstream) {
-        console.warn("Falling back to hosted versions at w3c-test.org");
-        urlPrefix = "http://w3c-test.org/";
-      }
-      serverHasStarted();
-      return;
-    }
-
-    const configArg = path.relative(path.resolve(wptDir), configPath);
-    const args = ["./wpt.py", "serve", "--config", configArg];
-    const python = childProcess.spawn("python", args, {
-      cwd: wptDir,
-      stdio: "inherit"
-    });
-
-    python.on("error", e => {
-      console.warn();
-      console.warn("Error starting python server process:", e.message);
-
-      if (toUpstream) {
-        console.error("Cannot proceed with running the tests.");
-        process.exit(1);
-      } else {
-        console.warn("Falling back to hosted versions at w3ctest.org");
-        urlPrefix = "http://w3c-test.org/";
-        serverHasStarted();
-      }
-    });
-
-    pollForServer(() => urlPrefix).then(serverHasStarted);
-
-    process.on("exit", () => {
-      // Python doesn't register a default handler for SIGTERM and it doesn't run __exit__() methods of context managers
-      // when it gets that signal. Using SIGINT avoids this problem
-      python.kill("SIGINT");
-    });
-  });
-
   return (testPath, title = testPath) => {
     specify({
       title,
@@ -99,22 +24,12 @@ module.exports = ({ toUpstream = false } = {}) => {
       slow: 10000,
       skipIfBrowser: true,
       fn() {
-        return server.started.then(() => createJSDOM(urlPrefix, testPath));
+        return createJSDOM(urlPrefixFactory(), testPath);
       }
     });
   };
 };
 
-function pollForServer(urlGetter) {
-  console.log("Checking if the web platform tests server is up");
-  return requestHead(urlGetter())
-    .then(() => console.log("Server is up!"))
-    .catch(err => {
-      console.log(`Server is not up yet (${err.message}); trying again`);
-      return q.delay(500).then(() => pollForServer(urlGetter));
-    });
-}
-
 function createJSDOM(urlPrefix, testPath) {
   const reporterPathname = "/resources/testharnessreport.js";
   const unhandledExceptions = [];
diff --git a/test/web-platform-tests/run-tuwpts.js b/test/web-platform-tests/run-tuwpts.js
index f7b69cea8a..65a99fc0fc 100644
--- a/test/web-platform-tests/run-tuwpts.js
+++ b/test/web-platform-tests/run-tuwpts.js
@@ -1,13 +1,13 @@
 "use strict";
 const path = require("path");
-const { describe } = require("mocha-sugar-free");
+const { describe, before } = require("mocha-sugar-free");
 const { spawnSync } = require("child_process");
 const { readManifest, getPossibleTestFilePaths } = require("./wpt-manifest-utils.js");
+const startWPTServer = require("./start-wpt-server.js");
 
 const wptPath = path.resolve(__dirname, "tests");
 const testsPath = path.resolve(__dirname, "to-upstream");
 const manifestFilename = path.resolve(__dirname, "tuwpt-manifest.json");
-const runSingleWPT = require("./run-single-wpt.js")({ toUpstream: true });
 
 // We can afford to re-generate the manifest each time; we have few enough files that it's cheap.
 const testsRootArg = path.relative(wptPath, testsPath);
@@ -18,6 +18,14 @@ spawnSync("python", args, { cwd: wptPath, stdio: "inherit" });
 const manifest = readManifest(manifestFilename);
 const possibleTestFilePaths = getPossibleTestFilePaths(manifest);
 
+let wptServerURL;
+const runSingleWPT = require("./run-single-wpt.js")(() => wptServerURL);
+before({ timeout: 30 * 1000 }, () => {
+  return startWPTServer({ toUpstream: true }).then(url => {
+    wptServerURL = url;
+  });
+});
+
 describe("Local tests in web-platform-test format (to-upstream)", () => {
   for (const test of possibleTestFilePaths) {
     runSingleWPT(test);
diff --git a/test/web-platform-tests/run-wpts.js b/test/web-platform-tests/run-wpts.js
index d9b475ad7a..3aaaf05b54 100644
--- a/test/web-platform-tests/run-wpts.js
+++ b/test/web-platform-tests/run-wpts.js
@@ -3,9 +3,9 @@ const path = require("path");
 const fs = require("fs");
 const jsYAML = require("js-yaml");
 const { Minimatch } = require("minimatch");
-const { describe, specify } = require("mocha-sugar-free");
+const { describe, specify, before } = require("mocha-sugar-free");
 const { readManifest, getPossibleTestFilePaths, stripPrefix } = require("./wpt-manifest-utils.js");
-const runSingleWPT = require("./run-single-wpt.js")({ toUpstream: false });
+const startWPTServer = require("./start-wpt-server.js");
 
 const validReasons = new Set(["fail", "timeout", "needs-await", "needs-node8"]);
 
@@ -30,6 +30,14 @@ const minimatchers = new Map();
 
 checkToRun();
 
+let wptServerURL;
+const runSingleWPT = require("./run-single-wpt.js")(() => wptServerURL);
+before({ timeout: 30 * 1000 }, () => {
+  return startWPTServer({ toUpstream: false }).then(url => {
+    wptServerURL = url;
+  });
+});
+
 describe("web-platform-tests", () => {
   for (const toRunDoc of toRunDocs) {
     describe(toRunDoc.DIR, () => {
diff --git a/test/web-platform-tests/start-wpt-server.js b/test/web-platform-tests/start-wpt-server.js
new file mode 100644
index 0000000000..e4c3731b1c
--- /dev/null
+++ b/test/web-platform-tests/start-wpt-server.js
@@ -0,0 +1,74 @@
+"use strict";
+/* eslint-disable no-console, global-require */
+const path = require("path");
+const dns = require("dns");
+const childProcess = require("child_process");
+const q = require("q");
+const { inBrowserContext } = require("../util.js");
+const requestHead = require("request-promise-native").head;
+const dnsLookup = q.denodeify(dns.lookup);
+
+const wptDir = path.resolve(__dirname, "tests");
+
+const configPaths = {
+  default: path.resolve(__dirname, "wpt-config.json"),
+  toUpstream: path.resolve(__dirname, "tuwpt-config.json")
+};
+
+const configs = {
+  default: require(configPaths.default),
+  toUpstream: require(configPaths.toUpstream)
+};
+
+module.exports = ({ toUpstream = false } = {}) => {
+  if (inBrowserContext()) {
+    return Promise.resolve();
+  }
+
+  const configType = toUpstream ? "toUpstream" : "default";
+  const configPath = configPaths[configType];
+  const config = configs[configType];
+
+  const urlPrefix = `http://${config.host}:${config.ports.http[0]}/`;
+
+  return dnsLookup("web-platform.test").then(
+    () => {
+      const configArg = path.relative(path.resolve(wptDir), configPath);
+      const args = ["./wpt.py", "serve", "--config", configArg];
+      const python = childProcess.spawn("python", args, {
+        cwd: wptDir,
+        stdio: "inherit"
+      });
+
+      return new Promise((resolve, reject) => {
+        python.on("error", e => {
+          reject(new Error("Error starting python server process:", e.message));
+        });
+
+        resolve(pollForServer(urlPrefix));
+
+        process.on("exit", () => {
+          // Python doesn't register a default handler for SIGTERM and it doesn't run __exit__() methods of context
+          // managers when it gets that signal. Using SIGINT avoids this problem.
+          python.kill("SIGINT");
+        });
+      });
+    },
+    () => {
+      throw new Error("Host entries not present for web platform tests. See " +
+                      "https://github.com/w3c/web-platform-tests#running-the-tests");
+    }
+  );
+};
+
+function pollForServer(url) {
+  return requestHead(url)
+    .then(() => {
+      console.log(`WPT server at ${url} is up!`);
+      return url;
+    })
+    .catch(err => {
+      console.log(`WPT server at ${url} is not up yet (${err.message}); trying again`);
+      return q.delay(500).then(() => pollForServer(url));
+    });
+}