--- a/mobile/android/geckoview/src/androidTest/java/org/mozilla/geckoview/test/ContentDelegateTest.kt
+++ b/mobile/android/geckoview/src/androidTest/java/org/mozilla/geckoview/test/ContentDelegateTest.kt
@@ -7,24 +7,28 @@ package org.mozilla.geckoview.test
 import org.mozilla.geckoview.GeckoResult
 import org.mozilla.geckoview.GeckoSession
 import org.mozilla.geckoview.test.rule.GeckoSessionTestRule.AssertCalled
 import org.mozilla.geckoview.test.rule.GeckoSessionTestRule.IgnoreCrash
 import org.mozilla.geckoview.test.rule.GeckoSessionTestRule.ReuseSession
 import org.mozilla.geckoview.test.rule.GeckoSessionTestRule.WithDevToolsAPI
 import org.mozilla.geckoview.test.rule.GeckoSessionTestRule.WithDisplay
 import org.mozilla.geckoview.test.util.Callbacks
+import org.mozilla.geckoview.test.util.UiThreadUtils
 
+import android.os.Looper
 import android.support.test.filters.MediumTest
 import android.support.test.runner.AndroidJUnit4
 import org.hamcrest.Matchers.*
 import org.junit.Assume.assumeThat
 import org.junit.Test
 import org.junit.runner.RunWith
 
+import kotlin.concurrent.thread
+
 @RunWith(AndroidJUnit4::class)
 @MediumTest
 class ContentDelegateTest : BaseSessionTest() {
 
     @Test fun titleChange() {
         sessionRule.session.loadTestPath(TITLE_CHANGE_HTML_PATH)
 
         sessionRule.waitUntilCalled(object : Callbacks.ContentDelegate {
@@ -150,9 +154,34 @@ class ContentDelegateTest : BaseSessionT
         assertThat("'name' field should match",
                 mainSession.evaluateJS("$('#name').value").toString(),
                 equalTo("the name"))
 
         assertThat("Scroll position should match",
                 mainSession.evaluateJS("window.scrollY") as Double,
                 closeTo(100.0, .5))
     }
+
+    @Test fun saveStateSync() {
+        val startUri = createTestUrl(SAVE_STATE_PATH)
+        mainSession.loadUri(startUri)
+        sessionRule.waitForPageStop()
+
+        var worker = thread {
+            Looper.prepare()
+
+            var thread = Thread.currentThread()
+            mainSession.saveState().then<Void> { _: GeckoSession.SessionState? ->
+                assertThat("We should be on the worker thread", Thread.currentThread(),
+                        equalTo(thread))
+                Looper.myLooper().quit()
+                null
+            }
+
+            Looper.loop()
+        }
+
+        worker.join(sessionRule.timeoutMillis)
+        if (worker.isAlive) {
+            throw UiThreadUtils.TimeoutException("Timed out")
+        }
+    }
 }

--- a/mobile/android/geckoview/src/androidTest/java/org/mozilla/geckoview/test/rule/GeckoSessionTestRule.java
+++ b/mobile/android/geckoview/src/androidTest/java/org/mozilla/geckoview/test/rule/GeckoSessionTestRule.java
@@ -920,16 +920,25 @@ public class GeckoSessionTestRule extend
      *
      * @return ErrorCollector or null.
      */
     public @Nullable ErrorCollector getErrorCollector() {
         return mErrorCollector;
     }
 
     /**
+     * Get the current timeout value in milliseconds.
+     *
+     * @return The current timeout value in milliseconds.
+     */
+    public long getTimeoutMillis() {
+        return mTimeoutMillis;
+    }
+
+    /**
      * Assert a condition with junit.Assert or an error collector.
      *
      * @param reason Reason string
      * @param value Value to check
      * @param matcher Matcher for checking the value
      */
     public <T> void checkThat(final String reason, final T value, final Matcher<? super T> matcher) {
         if (mErrorCollector != null) {