[memory-infra] Add unittests for peak detection and NotifyDumpTriggered

base/trace_event/memory_dump_scheduler_unittest.cc

Index: base/trace_event/memory_dump_scheduler_unittest.cc
diff --git a/base/trace_event/memory_dump_scheduler_unittest.cc b/base/trace_event/memory_dump_scheduler_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..05344d5e1f2d8b8c0ffa9840391bcac7f845d370
--- /dev/null
+++ b/base/trace_event/memory_dump_scheduler_unittest.cc
@@ -0,0 +1,95 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "base/trace_event/memory_dump_scheduler.h"
+
+#include <memory>
+
+#include "base/single_thread_task_runner.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace base {
+namespace trace_event {
+
+class MemoryDumpSchedulerPollingTest : public testing::Test {
+ public:
+  static const uint32_t kMinPollsToDump = 5;
+
+  MemoryDumpSchedulerPollingTest()
+      : testing::Test(),
+        num_samples_tracked_(
+            MemoryDumpScheduler::PollingTriggerState::kMaxNumMemorySamples) {}
+
+  void SetUp() override {
+    MemoryDumpScheduler::SetPollingIntervalForTesting(1);
+    uint32_t kMinPollsToDump = 5;
+    mds_.reset(new MemoryDumpScheduler(nullptr, nullptr));
+    mds_->AddTrigger(MemoryDumpType::PEAK_MEMORY_USAGE,
+                     MemoryDumpLevelOfDetail::LIGHT, kMinPollsToDump);
+    mds_->polling_state_.ResetTotals();
+    mds_->polling_state_.current_state =
+        MemoryDumpScheduler::PollingTriggerState::ENABLED;
+  }
+
+  void TearDown() override {
+    mds_->polling_state_.current_state =
+        MemoryDumpScheduler::PollingTriggerState::DISABLED;
+    mds_.reset();
+  }
+
+ protected:
+  bool ShouldTriggerDump(uint64_t total) {
+    return mds_->ShouldTriggerDump(total);
+  }
+
+  uint32_t num_samples_tracked_;
+  std::unique_ptr<MemoryDumpScheduler> mds_;
+};
+
+TEST_F(MemoryDumpSchedulerPollingTest, PeakDetection) {
+  for (uint32_t i = 0; i < num_samples_tracked_ * 6; ++i) {
+    // Memory is increased in steps and dumps must be triggered at every step.
+    uint64_t total = (2 + (i / (2 * num_samples_tracked_))) * 1024 * 1204;
+    bool did_trigger = ShouldTriggerDump(total);
+    // Dumps must be triggered only at specific iterations.
+    bool should_have_triggered = i == 0;
+    should_have_triggered |=
+        (i > num_samples_tracked_) && (i % (2 * num_samples_tracked_) == 1);
+    if (should_have_triggered) {
+      ASSERT_TRUE(did_trigger) << "Dump wasn't triggered at " << i;
+    } else {
+      ASSERT_FALSE(did_trigger) << "Unexpected dump at " << i;
+    }
+  }
+}
+
+TEST_F(MemoryDumpSchedulerPollingTest, SlowGrowthDetection) {
+  for (uint32_t i = 0; i < 15; ++i) {
+    // Record 1GiB of increase in each call. Dumps are triggered with 1% w.r.t
+    // system's total memory.
+    uint64_t total = static_cast<uint64_t>(i + 1) * 1024 * 1024 * 1024;
+    bool did_trigger = ShouldTriggerDump(total);
+    bool should_have_triggered = i % kMinPollsToDump == 0;
+    if (should_have_triggered) {
+      ASSERT_TRUE(did_trigger) << "Dump wasn't triggered at " << i;
+    } else {
+      ASSERT_FALSE(did_trigger) << "Unexpected dump at " << i;
+    }
+  }
+}
+
+TEST_F(MemoryDumpSchedulerPollingTest, NotifyDumpTriggered) {
+  for (uint32_t i = 0; i < num_samples_tracked_ * 6; ++i) {
+    uint64_t total = (2 + (i / (2 * num_samples_tracked_))) * 1024 * 1204;
+    if (i % num_samples_tracked_ == 0)
+      mds_->NotifyDumpTriggered();
+    bool did_trigger = ShouldTriggerDump(total);
+    // Dumps should never be triggered since NotifyDumpTriggered() is called
+    // frequently.
+    ASSERT_FALSE(did_trigger && i);
+  }
+}
+
+}  // namespace trace_event
+}  // namespace base