diff --git a/libwvdrmengine/cdm/core/test/reboot_test.cpp b/libwvdrmengine/cdm/core/test/reboot_test.cpp
index 58d736e1..3cedd366 100644
--- a/libwvdrmengine/cdm/core/test/reboot_test.cpp
+++ b/libwvdrmengine/cdm/core/test/reboot_test.cpp
@@ -11,6 +11,7 @@
 #include <sstream>
 
 #include "log.h"
+#include "test_sleep.h"
 
 using wvutil::a2b_hex;
 using wvutil::FileSystem;
@@ -227,6 +228,23 @@ void RebootTest::TearDown() {
   WvCdmTestBase::TearDown();
 }
 
+int64_t RebootTest::LoadTime(const std::string& key) {
+  int64_t value = 0;
+  std::istringstream input(persistent_data_[key]);
+  input >> value;
+  if (input.fail()) {
+    LOGE("Could not parse time '%s'", persistent_data_[key].c_str());
+  }
+  if (!input.eof()) {
+    LOGE("Extra text at end of time '%s'", persistent_data_[key].c_str());
+  }
+  return value;
+}
+
+void RebootTest::SaveTime(const std::string& key, int64_t time) {
+  persistent_data_[key] = std::to_string(time);
+}
+
 /** Test the dump and restore functions above. This does not test CDM
     functionality. */
 TEST_F(RebootTest, TestDumpUtil) {
@@ -277,4 +295,20 @@ TEST_F(RebootTest, FilesArePersistent) {
   }
 }
 
+/** Verify that the clock moves forward over a reboot. */
+TEST_F(RebootTest, TimeMovesForward) {
+  wvutil::TestSleep::Sleep(2);
+  const int64_t start = wvutil::Clock().GetCurrentTime();
+  wvutil::TestSleep::Sleep(2);
+  const int64_t end = wvutil::Clock().GetCurrentTime();
+  EXPECT_NEAR(end - start, 2.0, 1.0);
+  const std::string key = "end_time";
+  if (test_pass() == 0) {
+    // Save off the end of pass 1.
+    SaveTime(key, end);
+  } else {
+    int64_t previous_end = LoadTime(key);
+    EXPECT_LT(previous_end, start);
+  }
+}
 }  // namespace wvcdm
diff --git a/libwvdrmengine/cdm/core/test/reboot_test.h b/libwvdrmengine/cdm/core/test/reboot_test.h
index a0649bb1..0a9234be 100644
--- a/libwvdrmengine/cdm/core/test/reboot_test.h
+++ b/libwvdrmengine/cdm/core/test/reboot_test.h
@@ -36,6 +36,12 @@ class RebootTest : public WvCdmTestBaseWithEngine {
 
   static int test_pass() { return default_config_.test_pass(); }
 
+  // Load a previously saved time. Returns 0 if the value does not exist or
+  // cannot be parsed.
+  int64_t LoadTime(const std::string& key);
+  // Save a time to persistent storage.
+  void SaveTime(const std::string& key, int64_t time);
+
  protected:
   void SetUp() override;
   void TearDown() override;
diff --git a/libwvdrmengine/cdm/core/test/test_base.cpp b/libwvdrmengine/cdm/core/test/test_base.cpp
index 1543acd5..3cfacd6e 100644
--- a/libwvdrmengine/cdm/core/test/test_base.cpp
+++ b/libwvdrmengine/cdm/core/test/test_base.cpp
@@ -122,6 +122,12 @@ void show_menu(const char* prog_name, const std::string& extra_help_text) {
             << "    be used with a real OEMCrypto." << std::endl
             << std::endl;
 
+  std::cout << "  --initial_time=<time>" << std::endl;
+  std::cout
+      << "    Set the initial time on the fake clock. This is ignored"
+      << "    if fake_sleep was not set." << std::endl
+      << std::endl;
+
   std::cout << "  --pass=<N>" << std::endl;
   std::cout << "    Run test pass N. This is used for reboot tests that "
             << "require several passes." << std::endl
@@ -521,6 +527,14 @@ bool WvCdmTestBase::Initialize(int argc, const char* const argv[],
         default_config_.set_test_pass(std::stoi(arg_value));
         std::cout << "Running test pass " << default_config_.test_pass()
                   << std::endl;
+      } else if (arg_prefix == "--initial_time") {
+        if (wvutil::TestSleep::real_sleep()) {
+          LOGD("Ignoring initial time %s because using a real clock",
+               arg_value.c_str());
+        } else {
+          LOGE("Setting initial fake clock time to %s", arg_value.c_str());
+          wvutil::TestSleep::SetFakeClock(stol(arg_value));
+        }
       } else if (arg_prefix == "--test_data_path") {
         default_config_.set_test_data_path(arg_value);
       } else {
diff --git a/libwvdrmengine/cdm/util/test/test_sleep.cpp b/libwvdrmengine/cdm/util/test/test_sleep.cpp
index 4ca4b871..281e0429 100644
--- a/libwvdrmengine/cdm/util/test/test_sleep.cpp
+++ b/libwvdrmengine/cdm/util/test/test_sleep.cpp
@@ -58,6 +58,21 @@ void TestSleep::SyncFakeClock() {
   Sleep(0);
 }
 
+void TestSleep::SetFakeClock(int64_t time_seconds) {
+  if (real_sleep_) {
+    LOGE("SetFakeClock when using a real clock. Expect other failures.");
+  }
+  // Delta could be positive or negative. If the fake clock had been initialized
+  // by the current time on a real clock, and then the command line
+  // re-initializes it to 0, then delta is negative.
+  int64_t delta = time_seconds - Clock().GetCurrentTime();
+  if (callback_ != nullptr) {
+    callback_->ElapseTime(delta * 1000);
+  } else {
+    LOGE("Setting fake clock with no callback. This won't work.");
+  }
+}
+
 bool TestSleep::RollbackSystemTime(int seconds) {
   if (real_sleep_) {
 #ifdef _WIN32
diff --git a/libwvdrmengine/cdm/util/test/test_sleep.h b/libwvdrmengine/cdm/util/test/test_sleep.h
index 28db0b0a..155b89dc 100644
--- a/libwvdrmengine/cdm/util/test/test_sleep.h
+++ b/libwvdrmengine/cdm/util/test/test_sleep.h
@@ -41,6 +41,10 @@ class TestSleep {
   // verify this function does not roll back the clock used by OEMCrypto.
   static bool RollbackSystemTime(int seconds);
 
+  // Set the system clock to the specified time. This is only expected to work
+  // when real_sleep is false.
+  static void SetFakeClock(int64_t time_seconds);
+
   // Roll the system clock forward to undo all previous calls to
   // RollBackSystemTime. Returns true on success.
   static bool ResetRollback() {