diff --git a/extensions/cookie/test/unit/head_cookies.js b/extensions/cookie/test/unit/head_cookies.js
index 118ca3e0e949..d15c1f949ef3 100644
--- a/extensions/cookie/test/unit/head_cookies.js
+++ b/extensions/cookie/test/unit/head_cookies.js
@@ -477,19 +477,26 @@ CookieDatabaseConnection.prototype =
   }
 }
 
-// Count the cookies from 'host' in a database.
+// Count the cookies from 'host' in a database. If 'host' is null, count all
+// cookies.
 function do_count_cookies_in_db(profile, host)
 {
   let file = profile.clone();
   file.append("cookies.sqlite");
   let connection = Services.storage.openDatabase(file);
 
-  let select = connection.createStatement(
-    "SELECT COUNT(1) FROM moz_cookies WHERE host = :host");
-  select.bindByName("host", host);
+  let select = null;
+  if (host) {
+    select = connection.createStatement(
+      "SELECT COUNT(1) FROM moz_cookies WHERE host = :host");
+    select.bindByName("host", host);
+  } else {
+    select = connection.createStatement(
+      "SELECT COUNT(1) FROM moz_cookies");
+  }
+
   select.executeStep();
   let result = select.getInt32(0);
-
   select.reset();
   select.finalize();
   connection.close();
diff --git a/extensions/cookie/test/unit/test_cookies_read.js b/extensions/cookie/test/unit/test_cookies_read.js
index 3691a91d59d9..dc3007bd0dbe 100644
--- a/extensions/cookie/test/unit/test_cookies_read.js
+++ b/extensions/cookie/test/unit/test_cookies_read.js
@@ -29,6 +29,22 @@ function do_run_test() {
 
   do_check_eq(do_count_cookies(), 3000);
 
+  // Wait until all 3000 cookies have been written out to the database.
+  let db = new CookieDatabaseConnection(profile, 4);
+  while (do_count_cookies_in_db(profile) < 3000) {
+    do_execute_soon(function() {
+      do_run_generator(test_generator);
+    });
+    yield;
+  }
+
+  // Check the WAL file size. We set it to 16 pages of 32k, which means it
+  // should be around 500k.
+  let file = db.db.databaseFile;
+  do_check_true(file.exists());
+  do_check_true(file.fileSize < 1e6);
+  db.close();
+
   // fake a profile change
   do_close_profile(test_generator);
   yield;