Add unit tests for sub-components of CaptureScheduler.

remoting/base/rate_counter.cc

Index: remoting/base/rate_counter.cc
diff --git a/remoting/base/rate_counter.cc b/remoting/base/rate_counter.cc
index fff9b6cebcd18f3734cf7e5c9ed1c925b36fc1a4..49466fa2209772286fed01d800e3bd0f14d19b5c 100644
--- a/remoting/base/rate_counter.cc
+++ b/remoting/base/rate_counter.cc
@@ -4,6 +4,8 @@
 
 #include "remoting/base/rate_counter.h"
 
+#include "base/logging.h"

[alexeypa (please no reviews), 2013/03/18 19:39:39]

Is this header actually used?

[Wez, 2013/03/19 23:23:14]

No; used it during development. It's needed for the suggested CHECKs, though.

+
 namespace remoting {
 
 RateCounter::RateCounter(base::TimeDelta time_window)
@@ -15,24 +17,29 @@ RateCounter::~RateCounter() {
 }
 
 void RateCounter::Record(int64 value) {
-  base::Time current_time = base::Time::Now();
-  Evict(current_time);
+  base::Time current_time = CurrentTime();
 
   base::AutoLock auto_lock(lock_);
+  EvictOldDataPoints(current_time);
   sum_ += value;
   data_points_.push(std::make_pair(current_time, value));
 }
 
 double RateCounter::Rate() {
-  Evict(base::Time::Now());
+  base::Time current_time = CurrentTime();

[alexeypa (please no reviews), 2013/03/18 19:39:39]

Should CurrentTime() be called under the lock?

[Wez, 2013/03/19 23:23:14]

No, I don't think so.  This way it captures the time at which the call was made.

 
   base::AutoLock auto_lock(lock_);
+  EvictOldDataPoints(current_time);
   return static_cast<double>(base::Time::kMillisecondsPerSecond) * sum_ /

[alexeypa (please no reviews), 2013/03/18 19:39:39]

nit: Since it is converting to double anyway it will be shorter if you write it
as:

return static_cast<double>(sum_) / time_window_.InSecondsF();

Or even:

return sum_ / time_window_.InSecondsF();

[Wez, 2013/03/19 23:23:14]

Done.

       time_window_.InMilliseconds();
 }
 
-void RateCounter::Evict(base::Time current_time) {
-  base::AutoLock auto_lock(lock_);
+void RateCounter::SetCurrentTimeForTest(base::Time current_time) {
+  current_time_for_test_ = current_time;
+}
+
+void RateCounter::EvictOldDataPoints(base::Time current_time) {
+  lock_.AssertAcquired();
 
   // Remove data points outside of the window.
   base::Time window_start = current_time - time_window_;
@@ -46,4 +53,10 @@ void RateCounter::Evict(base::Time current_time) {
   }
 }
 
+base::Time RateCounter::CurrentTime() const {
+  if (current_time_for_test_ == base::Time())
+    return base::Time::Now();
+  return current_time_for_test_;
+}
+
 }  // namespace remoting