diff --git a/libwvdrmengine/cdm/core/test/reboot_test.cpp b/libwvdrmengine/cdm/core/test/reboot_test.cpp
index 32950f7b..39e208b2 100644
--- a/libwvdrmengine/cdm/core/test/reboot_test.cpp
+++ b/libwvdrmengine/cdm/core/test/reboot_test.cpp
@@ -223,9 +223,11 @@ void RebootTest::SetUp() {
     EXPECT_EQ(read, file_size) << "Error reading persistent data file.";
     EXPECT_TRUE(ParseDump(dump, &persistent_data_));
   }
+  TestSleep::SyncFakeClock();
 }
 
 void RebootTest::TearDown() {
+  TestSleep::SyncFakeClock();
   auto file = file_system_->Open(persistent_data_filename_,
                                  FileSystem::kCreate | FileSystem::kTruncate);
   ASSERT_TRUE(file) << "Failed to open file: " << persistent_data_filename_;
@@ -405,6 +407,7 @@ class OfflineLicense {
   // Fetch and load the license. The session is left open.
   void LoadLicense() {
     license_holder_.OpenSession();
+    TestSleep::SyncFakeClock();
     start_of_rental_clock_ = wvutil::Clock().GetCurrentTime();
     license_holder_.FetchLicense();
     license_holder_.LoadLicense();
@@ -434,6 +437,7 @@ class OfflineLicense {
 
   // Verify that the license may be used to decrypt content.
   void Decrypt() {
+    TestSleep::SyncFakeClock();
     if (start_of_playback_ == 0) {
       start_of_playback_ = wvutil::Clock().GetCurrentTime();
     }
@@ -451,6 +455,7 @@ class OfflineLicense {
   // Verify that the license has expired, and may not be used to decrypt
   // content.
   void FailDecrypt() {
+    TestSleep::SyncFakeClock();
     const KeyId key_id = "0000000000000000";
     EXPECT_EQ(NEED_KEY, license_holder_.Decrypt(key_id))
         << "Decrypt should have failed for " << content_id_
@@ -629,6 +634,7 @@ class OfflineLicenseTest : public RebootTest {
     int decrypt_count = 0;
     int fail_count = 0;
     for (auto time : interesting_times_) {
+      TestSleep::SyncFakeClock();
       int64_t now = wvutil::Clock().GetCurrentTime();
       int64_t delta = (time - now);
       // It is not necessarily an error for the delta to be negative. But it is
@@ -673,6 +679,7 @@ class OfflineLicenseTest : public RebootTest {
       for (size_t i = first_valid_[n] + 1; i < test_case_[n].size(); i++) {
         OfflineLicense* license = test_case_[n][i].get();
         ASSERT_NO_FATAL_FAILURE(license->ReloadLicense());
+        TestSleep::SyncFakeClock();
         int64_t now = wvutil::Clock().GetCurrentTime();
         if (now <= license->cutoff() - kFudge) {
           license->Decrypt();
diff --git a/libwvdrmengine/cdm/util/test/test_clock.cpp b/libwvdrmengine/cdm/util/test/test_clock.cpp
index 18331bb6..33edd9c3 100644
--- a/libwvdrmengine/cdm/util/test/test_clock.cpp
+++ b/libwvdrmengine/cdm/util/test/test_clock.cpp
@@ -2,7 +2,9 @@
 // source code may only be used and distributed under the Widevine License
 // Agreement.
 //
-// Clock - A fake clock just for running tests.
+// Clock - A fake clock just for running tests. This is used when running
+// OEMCrypto unit tests. It is not used when tests include the CE CDM source
+// code because that uses the clock in cdm/test_host.cpp instead.
 
 #include <chrono>