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/DefaultCommandTest.cpp

@@ -0,0 +1,48 @@
+/*----------------------------------------------------------------------------*/
+/* 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/RunCommand.h"
+
+using namespace frc2;
+class DefaultCommandTest : public CommandTestBase {};
+
+TEST_F(DefaultCommandTest, DefaultCommandScheduleTest) {
+  CommandScheduler scheduler = GetScheduler();
+
+  TestSubsystem subsystem;
+
+  RunCommand command1([] {}, {&subsystem});
+
+  scheduler.SetDefaultCommand(&subsystem, std::move(command1));
+  auto handle = scheduler.GetDefaultCommand(&subsystem);
+  scheduler.Run();
+
+  EXPECT_TRUE(scheduler.IsScheduled(handle));
+}
+
+TEST_F(DefaultCommandTest, DefaultCommandInterruptResumeTest) {
+  CommandScheduler scheduler = GetScheduler();
+
+  TestSubsystem subsystem;
+
+  RunCommand command1([] {}, {&subsystem});
+  RunCommand command2([] {}, {&subsystem});
+
+  scheduler.SetDefaultCommand(&subsystem, std::move(command1));
+  auto handle = scheduler.GetDefaultCommand(&subsystem);
+  scheduler.Run();
+  scheduler.Schedule(&command2);
+
+  EXPECT_TRUE(scheduler.IsScheduled(&command2));
+  EXPECT_FALSE(scheduler.IsScheduled(handle));
+
+  scheduler.Cancel(&command2);
+  scheduler.Run();
+
+  EXPECT_TRUE(scheduler.IsScheduled(handle));
+}