diff --git a/browser/modules/test/unit/test_SiteDataManager.js b/browser/modules/test/unit/test_SiteDataManager.js
index 9d4d2e3d84d0..5e2ec254b0ff 100644
--- a/browser/modules/test/unit/test_SiteDataManager.js
+++ b/browser/modules/test/unit/test_SiteDataManager.js
@@ -5,6 +5,7 @@
 
 const EXAMPLE_ORIGIN = "https://www.example.com";
 const EXAMPLE_ORIGIN_2 = "https://example.org";
+const EXAMPLE_ORIGIN_3 = "http://localhost:8000";
 
 const { Services } = ChromeUtils.import("resource://gre/modules/Services.jsm");
 const { SiteDataManager } = ChromeUtils.import(
@@ -130,11 +131,18 @@ add_task(async function testRemove() {
   SiteDataTestUtils.addToCookies(EXAMPLE_ORIGIN_2, "foo", "bar");
   await SiteDataTestUtils.addToIndexedDB(EXAMPLE_ORIGIN_2, 2048);
   await SiteDataTestUtils.persist(EXAMPLE_ORIGIN_2);
+  await SiteDataTestUtils.addToIndexedDB(EXAMPLE_ORIGIN_3, 2048);
 
   await SiteDataManager.updateSites();
 
   let sites = await SiteDataManager.getSites();
 
+  Assert.equal(sites.length, 3, "Has three sites.");
+
+  await SiteDataManager.remove(["localhost"]);
+
+  sites = await SiteDataManager.getSites();
+
   Assert.equal(sites.length, 2, "Has two sites.");
 
   await SiteDataManager.remove(["www.example.com"]);
diff --git a/toolkit/components/cleardata/tests/browser/browser_quota.js b/toolkit/components/cleardata/tests/browser/browser_quota.js
index 7a05398343dd..dd456e77d963 100644
--- a/toolkit/components/cleardata/tests/browser/browser_quota.js
+++ b/toolkit/components/cleardata/tests/browser/browser_quota.js
@@ -122,6 +122,7 @@ const ORG_DOMAIN = "example.com";
 const ORG_ORIGIN = `https://${ORG_DOMAIN}`;
 const COM_DOMAIN = "example.org";
 const COM_ORIGIN = `https://${COM_DOMAIN}`;
+const LH_DOMAIN = "localhost";
 
 add_task(async function test_deleteFromHost() {
   const sites = [
@@ -133,6 +134,10 @@ add_task(async function test_deleteFromHost() {
       args: [COM_DOMAIN, true, Ci.nsIClearDataService.CLEAR_DOM_QUOTA],
       origin: COM_ORIGIN,
     },
+    {
+      args: [LH_DOMAIN, true, Ci.nsIClearDataService.CLEAR_DOM_QUOTA],
+      origin: `http://${LH_DOMAIN}:8000`,
+    },
   ];
 
   await runTest(sites, Services.clearData.deleteDataFromHost);
@@ -202,3 +207,26 @@ add_task(async function test_deleteAll() {
   ok(!hasQuotaStorage(ORG_ORIGIN), `${ORG_ORIGIN} has no quota storage`);
   ok(!hasQuotaStorage(COM_ORIGIN), `${COM_ORIGIN} has no quota storage`);
 });
+
+add_task(async function test_deleteSubdomain() {
+  const ANOTHER_ORIGIN = `https://wwww.${ORG_DOMAIN}`;
+  info(`Adding quota storage`);
+  await addQuotaStorage(getPrincipal(ORG_ORIGIN));
+  await addQuotaStorage(getPrincipal(ANOTHER_ORIGIN));
+
+  info(`Verifying deleteDataFromHost for subdomain`);
+  await new Promise(aResolve => {
+    Services.clearData.deleteDataFromHost(
+      ORG_DOMAIN,
+      true,
+      Ci.nsIClearDataService.CLEAR_DOM_QUOTA,
+      value => {
+        Assert.equal(value, 0);
+        aResolve();
+      }
+    );
+  });
+
+  ok(!hasQuotaStorage(ORG_ORIGIN), `${ORG_ORIGIN} has no quota storage`);
+  ok(!hasQuotaStorage(COM_ORIGIN), `${ANOTHER_ORIGIN} has no quota storage`);
+});