deleted file mode 100644
--- a/toolkit/mozapps/extensions/test/addons/test_cacheflush1/install.rdf
+++ /dev/null
@@ -1,22 +0,0 @@
-<?xml version="1.0"?>
-
-<RDF xmlns="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
-     xmlns:em="http://www.mozilla.org/2004/em-rdf#">
-
-  <Description about="urn:mozilla:install-manifest">
-    <em:id>addon1@tests.mozilla.org</em:id>
-    <em:version>2.0</em:version>
-
-    <!-- Front End MetaData -->
-    <em:name>File Pointer Test</em:name>
-
-    <em:targetApplication>
-      <Description>
-        <em:id>xpcshell@tests.mozilla.org</em:id>
-        <em:minVersion>1</em:minVersion>
-        <em:maxVersion>1</em:maxVersion>
-      </Description>
-    </em:targetApplication>
-
-  </Description>
-</RDF>

deleted file mode 100644
--- a/toolkit/mozapps/extensions/test/addons/test_cacheflush2/install.rdf
+++ /dev/null
@@ -1,23 +0,0 @@
-<?xml version="1.0"?>
-
-<RDF xmlns="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
-     xmlns:em="http://www.mozilla.org/2004/em-rdf#">
-
-  <Description about="urn:mozilla:install-manifest">
-    <em:id>addon2@tests.mozilla.org</em:id>
-    <em:version>2.0</em:version>
-
-    <!-- Front End MetaData -->
-    <em:name>File Pointer Test</em:name>
-    <em:bootstrap>true</em:bootstrap>
-
-    <em:targetApplication>
-      <Description>
-        <em:id>xpcshell@tests.mozilla.org</em:id>
-        <em:minVersion>1</em:minVersion>
-        <em:maxVersion>1</em:maxVersion>
-      </Description>
-    </em:targetApplication>
-
-  </Description>
-</RDF>

--- a/toolkit/mozapps/extensions/test/xpcshell/test_cacheflush.js
+++ b/toolkit/mozapps/extensions/test/xpcshell/test_cacheflush.js
@@ -10,118 +10,141 @@ var gCacheFlushCount = 0;
 var CacheFlushObserver = {
   observe(aSubject, aTopic, aData) {
     if (aTopic != "flush-cache-entry")
       return;
     // Ignore flushes triggered by the fake cert DB
     if (aData == "cert-override")
       return;
 
-    Assert.ok(gExpectedFile != null);
-    Assert.ok(aSubject instanceof AM_Ci.nsIFile);
-    Assert.equal(aSubject.path, gExpectedFile.path);
+    ok(gExpectedFile != null);
+    ok(aSubject instanceof AM_Ci.nsIFile);
+    equal(aSubject.path, gExpectedFile.path);
     gCacheFlushCount++;
   }
 };
 
-function run_test() {
-  do_test_pending();
+const ADDONS = [
+  {
+    id: "addon1@tests.mozilla.org",
+    version: "2.0",
+    name: "Cache Flush Test",
+
+    targetApplications: [{
+      id: "xpcshell@tests.mozilla.org",
+      minVersion: "1",
+      maxVersion: "1" }],
+  },
+  {
+    id: "addon2@tests.mozilla.org",
+    version: "2.0",
+
+    name: "Cache Flush Test",
+    bootstrap: true,
+
+    targetApplications: [{
+      id: "xpcshell@tests.mozilla.org",
+      minVersion: "1",
+      maxVersion: "1" }],
+  },
+];
+
+const XPIS = ADDONS.map(addon => createTempXPIFile(addon));
+
+add_task(async function setup() {
   Services.obs.addObserver(CacheFlushObserver, "flush-cache-entry");
   createAppInfo("xpcshell@tests.mozilla.org", "XPCShell", "1", "2");
 
-  startupManager();
-
-  run_test_1();
-}
+  await promiseStartupManager();
+});
 
 // Tests that the cache is flushed when cancelling a pending install
-function run_test_1() {
-  AddonManager.getInstallForFile(do_get_addon("test_cacheflush1"), function(aInstall) {
-    completeAllInstalls([aInstall], function() {
-      // We should flush the staged XPI when cancelling the install
-      gExpectedFile = gProfD.clone();
-      gExpectedFile.append("extensions");
-      gExpectedFile.append("staged");
-      gExpectedFile.append("addon1@tests.mozilla.org.xpi");
-      aInstall.cancel();
+add_task(async function test_flush_pending_install() {
+  let install = await AddonManager.getInstallForFile(XPIS[0]);
+  await promiseCompleteInstall(install);
 
-      Assert.equal(gCacheFlushCount, 1);
-      gExpectedFile = null;
-      gCacheFlushCount = 0;
+  // We should flush the staged XPI when cancelling the install
+  gExpectedFile = gProfD.clone();
+  gExpectedFile.append("extensions");
+  gExpectedFile.append("staged");
+  gExpectedFile.append("addon1@tests.mozilla.org.xpi");
+  install.cancel();
 
-      run_test_2();
-    });
-  });
-}
+  equal(gCacheFlushCount, 1);
+  gExpectedFile = null;
+  gCacheFlushCount = 0;
+});
 
 // Tests that the cache is flushed when uninstalling an add-on
-function run_test_2() {
-  installAllFiles([do_get_addon("test_cacheflush1")], function() {
-    // Installing will flush the staged XPI during startup
-    gExpectedFile = gProfD.clone();
-    gExpectedFile.append("extensions");
-    gExpectedFile.append("staged");
-    gExpectedFile.append("addon1@tests.mozilla.org.xpi");
-    restartManager();
-    Assert.equal(gCacheFlushCount, 1);
-    gExpectedFile = null;
-    gCacheFlushCount = 0;
+add_task(async function test_flush_uninstall() {
+  await promiseInstallFile(XPIS[0]);
+
+  // Installing will flush the staged XPI during startup
+  gExpectedFile = gProfD.clone();
+  gExpectedFile.append("extensions");
+  gExpectedFile.append("staged");
+  gExpectedFile.append("addon1@tests.mozilla.org.xpi");
+
+  await promiseRestartManager();
+
+  equal(gCacheFlushCount, 1);
+  gExpectedFile = null;
+  gCacheFlushCount = 0;
 
-    AddonManager.getAddonByID("addon1@tests.mozilla.org", function(a1) {
-      // We should flush the installed XPI when uninstalling
-      Assert.ok(a1 != null);
-      a1.uninstall();
-      Assert.equal(gCacheFlushCount, 0);
+  let addon = await AddonManager.getAddonByID("addon1@tests.mozilla.org");
+  // We should flush the installed XPI when uninstalling
+  ok(addon != null);
+  addon.uninstall();
+  equal(gCacheFlushCount, 0);
 
-      gExpectedFile = gProfD.clone();
-      gExpectedFile.append("extensions");
-      gExpectedFile.append("addon1@tests.mozilla.org.xpi");
-      restartManager();
-      Assert.equal(gCacheFlushCount, 1);
-      gExpectedFile = null;
-      gCacheFlushCount = 0;
+  gExpectedFile = gProfD.clone();
+  gExpectedFile.append("extensions");
+  gExpectedFile.append("addon1@tests.mozilla.org.xpi");
 
-      executeSoon(run_test_3);
-    });
-  });
-}
+  await promiseRestartManager();
+
+  equal(gCacheFlushCount, 1);
+  gExpectedFile = null;
+  gCacheFlushCount = 0;
+});
 
 // Tests that the cache is flushed when installing a restartless add-on
-function run_test_3() {
-  AddonManager.getInstallForFile(do_get_addon("test_cacheflush2"), function(aInstall) {
-    aInstall.addListener({
+add_task(async function test_flush_restartless_install() {
+  let install = await AddonManager.getInstallForFile(XPIS[1]);
+
+  await new Promise(resolve => {
+    install.addListener({
       onInstallStarted() {
         // We should flush the staged XPI when completing the install
         gExpectedFile = gProfD.clone();
         gExpectedFile.append("extensions");
         gExpectedFile.append("staged");
         gExpectedFile.append("addon2@tests.mozilla.org.xpi");
       },
 
       onInstallEnded() {
-        Assert.equal(gCacheFlushCount, 1);
+        equal(gCacheFlushCount, 1);
         gExpectedFile = null;
         gCacheFlushCount = 0;
 
-        executeSoon(run_test_4);
+        resolve();
       }
     });
 
-    aInstall.install();
+    install.install();
   });
-}
+});
 
 // Tests that the cache is flushed when uninstalling a restartless add-on
-function run_test_4() {
-  AddonManager.getAddonByID("addon2@tests.mozilla.org", function(a2) {
-    // We should flush the installed XPI when uninstalling
-    gExpectedFile = gProfD.clone();
-    gExpectedFile.append("extensions");
-    gExpectedFile.append("addon2@tests.mozilla.org.xpi");
+add_task(async function test_flush_uninstall() {
+  let addon = await AddonManager.getAddonByID("addon2@tests.mozilla.org");
 
-    a2.uninstall();
-    Assert.equal(gCacheFlushCount, 1);
-    gExpectedFile = null;
-    gCacheFlushCount = 0;
+  // We should flush the installed XPI when uninstalling
+  gExpectedFile = gProfD.clone();
+  gExpectedFile.append("extensions");
+  gExpectedFile.append("addon2@tests.mozilla.org.xpi");
 
-    executeSoon(do_test_finished);
-  });
-}
+  addon.uninstall();
+
+  equal(gCacheFlushCount, 1);
+  gExpectedFile = null;
+  gCacheFlushCount = 0;
+});