Split the two command implementations into separate libraries (#2012)

This will allow us at the user code side to determine to include old commands, new commands or both.

wpilibNewCommands/src/test/native/cpp/frc2/command/SchedulerTest.cpp

@@ -0,0 +1,56 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) 2019 FIRST. All Rights Reserved.                             */
+/* Open Source Software - may be modified and shared by FRC teams. The code   */
+/* must be accompanied by the FIRST BSD license file in the root directory of */
+/* the project.                                                               */
+/*----------------------------------------------------------------------------*/
+
+#include "CommandTestBase.h"
+#include "frc2/command/InstantCommand.h"
+#include "frc2/command/RunCommand.h"
+
+using namespace frc2;
+class SchedulerTest : public CommandTestBase {};
+
+TEST_F(SchedulerTest, SchedulerLambdaTestNoInterrupt) {
+  CommandScheduler scheduler = GetScheduler();
+
+  InstantCommand command;
+
+  int counter = 0;
+
+  scheduler.OnCommandInitialize([&counter](const Command&) { counter++; });
+  scheduler.OnCommandExecute([&counter](const Command&) { counter++; });
+  scheduler.OnCommandFinish([&counter](const Command&) { counter++; });
+
+  scheduler.Schedule(&command);
+  scheduler.Run();
+
+  EXPECT_EQ(counter, 3);
+}
+
+TEST_F(SchedulerTest, SchedulerLambdaInterruptTest) {
+  CommandScheduler scheduler = GetScheduler();
+
+  RunCommand command([] {}, {});
+
+  int counter = 0;
+
+  scheduler.OnCommandInterrupt([&counter](const Command&) { counter++; });
+
+  scheduler.Schedule(&command);
+  scheduler.Run();
+  scheduler.Cancel(&command);
+
+  EXPECT_EQ(counter, 1);
+}
+
+TEST_F(SchedulerTest, UnregisterSubsystemTest) {
+  CommandScheduler scheduler = GetScheduler();
+
+  TestSubsystem system;
+
+  scheduler.RegisterSubsystem(&system);
+
+  EXPECT_NO_FATAL_FAILURE(scheduler.UnregisterSubsystem(&system));
+}