Add Debouncer (#3590)

Supersedes #2358 with updates and cleanups.

Closes #2482 and closes #2487 because we shouldn't support both
time-based and count-based debouncing approaches.

Co-authored-by: oblarg <emichaelbarnett@gmail.com>

wpilibNewCommands/src/test/native/cpp/frc2/command/button/ButtonTest.cpp

@@ -0,0 +1,210 @@
+// Copyright (c) FIRST and other WPILib contributors.
+// Open Source Software; you can modify and/or share it under the terms of
+// the WPILib BSD license file in the root directory of this project.
+
+#include <frc/simulation/SimHooks.h>
+
+#include "../CommandTestBase.h"
+#include "frc2/command/CommandScheduler.h"
+#include "frc2/command/RunCommand.h"
+#include "frc2/command/WaitUntilCommand.h"
+#include "frc2/command/button/Trigger.h"
+#include "gtest/gtest.h"
+
+using namespace frc2;
+class ButtonTest : public CommandTestBase {};
+
+TEST_F(ButtonTest, WhenPressed) {
+  auto& scheduler = CommandScheduler::GetInstance();
+  bool finished = false;
+  bool pressed = false;
+
+  WaitUntilCommand command([&finished] { return finished; });
+
+  Trigger([&pressed] { return pressed; }).WhenActive(&command);
+  scheduler.Run();
+  EXPECT_FALSE(scheduler.IsScheduled(&command));
+  pressed = true;
+  scheduler.Run();
+  EXPECT_TRUE(scheduler.IsScheduled(&command));
+  finished = true;
+  scheduler.Run();
+  EXPECT_FALSE(scheduler.IsScheduled(&command));
+}
+
+TEST_F(ButtonTest, WhenReleased) {
+  auto& scheduler = CommandScheduler::GetInstance();
+  bool finished = false;
+  bool pressed = false;
+  WaitUntilCommand command([&finished] { return finished; });
+
+  pressed = true;
+  Trigger([&pressed] { return pressed; }).WhenInactive(&command);
+  scheduler.Run();
+  EXPECT_FALSE(scheduler.IsScheduled(&command));
+  pressed = false;
+  scheduler.Run();
+  EXPECT_TRUE(scheduler.IsScheduled(&command));
+  finished = true;
+  scheduler.Run();
+  EXPECT_FALSE(scheduler.IsScheduled(&command));
+}
+
+TEST_F(ButtonTest, WhileHeld) {
+  auto& scheduler = CommandScheduler::GetInstance();
+  bool finished = false;
+  bool pressed = false;
+  WaitUntilCommand command([&finished] { return finished; });
+
+  pressed = false;
+  Trigger([&pressed] { return pressed; }).WhileActiveContinous(&command);
+  scheduler.Run();
+  EXPECT_FALSE(scheduler.IsScheduled(&command));
+  pressed = true;
+  scheduler.Run();
+  EXPECT_TRUE(scheduler.IsScheduled(&command));
+  finished = true;
+  scheduler.Run();
+  finished = false;
+  scheduler.Run();
+  EXPECT_TRUE(scheduler.IsScheduled(&command));
+  pressed = false;
+  scheduler.Run();
+  EXPECT_FALSE(scheduler.IsScheduled(&command));
+}
+
+TEST_F(ButtonTest, WhenHeld) {
+  auto& scheduler = CommandScheduler::GetInstance();
+  bool finished = false;
+  bool pressed = false;
+  WaitUntilCommand command([&finished] { return finished; });
+
+  pressed = false;
+  Trigger([&pressed] { return pressed; }).WhileActiveOnce(&command);
+  scheduler.Run();
+  EXPECT_FALSE(scheduler.IsScheduled(&command));
+  pressed = true;
+  scheduler.Run();
+  EXPECT_TRUE(scheduler.IsScheduled(&command));
+  finished = true;
+  scheduler.Run();
+  finished = false;
+  scheduler.Run();
+  EXPECT_FALSE(scheduler.IsScheduled(&command));
+
+  pressed = false;
+  Trigger([&pressed] { return pressed; }).WhileActiveOnce(&command);
+  pressed = true;
+  scheduler.Run();
+  pressed = false;
+  scheduler.Run();
+  EXPECT_FALSE(scheduler.IsScheduled(&command));
+}
+
+TEST_F(ButtonTest, ToggleWhenPressed) {
+  auto& scheduler = CommandScheduler::GetInstance();
+  bool finished = false;
+  bool pressed = false;
+  WaitUntilCommand command([&finished] { return finished; });
+
+  pressed = false;
+  Trigger([&pressed] { return pressed; }).ToggleWhenActive(&command);
+  scheduler.Run();
+  EXPECT_FALSE(scheduler.IsScheduled(&command));
+  pressed = true;
+  scheduler.Run();
+  EXPECT_TRUE(scheduler.IsScheduled(&command));
+  pressed = false;
+  scheduler.Run();
+  pressed = true;
+  scheduler.Run();
+  EXPECT_FALSE(scheduler.IsScheduled(&command));
+}
+
+TEST_F(ButtonTest, And) {
+  auto& scheduler = CommandScheduler::GetInstance();
+  bool finished = false;
+  bool pressed1 = false;
+  bool pressed2 = false;
+  WaitUntilCommand command([&finished] { return finished; });
+
+  (Trigger([&pressed1] { return pressed1; }) && Trigger([&pressed2] {
+     return pressed2;
+   })).WhenActive(&command);
+  pressed1 = true;
+  scheduler.Run();
+  EXPECT_FALSE(scheduler.IsScheduled(&command));
+  pressed2 = true;
+  scheduler.Run();
+  EXPECT_TRUE(scheduler.IsScheduled(&command));
+}
+
+TEST_F(ButtonTest, Or) {
+  auto& scheduler = CommandScheduler::GetInstance();
+  bool finished = false;
+  bool pressed1 = false;
+  bool pressed2 = false;
+  WaitUntilCommand command1([&finished] { return finished; });
+  WaitUntilCommand command2([&finished] { return finished; });
+
+  (Trigger([&pressed1] { return pressed1; }) || Trigger([&pressed2] {
+     return pressed2;
+   })).WhenActive(&command1);
+  pressed1 = true;
+  scheduler.Run();
+  EXPECT_TRUE(scheduler.IsScheduled(&command1));
+
+  pressed1 = false;
+
+  (Trigger([&pressed1] { return pressed1; }) || Trigger([&pressed2] {
+     return pressed2;
+   })).WhenActive(&command2);
+  pressed2 = true;
+  scheduler.Run();
+  EXPECT_TRUE(scheduler.IsScheduled(&command2));
+}
+
+TEST_F(ButtonTest, Negate) {
+  auto& scheduler = CommandScheduler::GetInstance();
+  bool finished = false;
+  bool pressed = true;
+  WaitUntilCommand command([&finished] { return finished; });
+
+  (!Trigger([&pressed] { return pressed; })).WhenActive(&command);
+  scheduler.Run();
+  EXPECT_FALSE(scheduler.IsScheduled(&command));
+  pressed = false;
+  scheduler.Run();
+  EXPECT_TRUE(scheduler.IsScheduled(&command));
+}
+
+TEST_F(ButtonTest, RValueButton) {
+  auto& scheduler = CommandScheduler::GetInstance();
+  int counter = 0;
+  bool pressed = false;
+
+  RunCommand command([&counter] { counter++; }, {});
+
+  Trigger([&pressed] { return pressed; }).WhenActive(std::move(command));
+  scheduler.Run();
+  EXPECT_EQ(counter, 0);
+  pressed = true;
+  scheduler.Run();
+  EXPECT_EQ(counter, 1);
+}
+
+TEST_F(ButtonTest, DebounceTest) {
+  auto& scheduler = CommandScheduler::GetInstance();
+  bool pressed = false;
+  RunCommand command([] {});
+
+  Trigger([&pressed] { return pressed; }).Debounce(100_ms).WhenActive(&command);
+  pressed = true;
+  scheduler.Run();
+  EXPECT_FALSE(scheduler.IsScheduled(&command));
+
+  frc::sim::StepTiming(300_ms);
+
+  scheduler.Run();
+  EXPECT_TRUE(scheduler.IsScheduled(&command));
+}