Add tests for SendableChooser and Command Sendable functionality (#5179)

wpilibc/src/test/native/cpp/smartdashboard/SendableChooserTest.cpp

@@ -0,0 +1,60 @@
+// 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/smartdashboard/SendableChooser.h>
+#include <frc/smartdashboard/SmartDashboard.h>
+
+#include <string>
+
+#include <networktables/NetworkTableInstance.h>
+
+#include "gtest/gtest.h"
+
+class SendableChooserTest : public ::testing::TestWithParam<int> {};
+
+TEST_P(SendableChooserTest, ReturnsSelected) {
+  frc::SendableChooser<int> chooser;
+
+  for (int i = 1; i <= 3; i++) {
+    chooser.AddOption(std::to_string(i), i);
+  }
+  chooser.SetDefaultOption("0", 0);
+
+  auto pub = nt::NetworkTableInstance::GetDefault()
+                 .GetStringTopic("/SmartDashboard/chooser/selected")
+                 .Publish();
+
+  frc::SmartDashboard::PutData("chooser", &chooser);
+  frc::SmartDashboard::UpdateValues();
+  pub.Set(std::to_string(GetParam()));
+  frc::SmartDashboard::UpdateValues();
+  EXPECT_EQ(GetParam(), chooser.GetSelected());
+}
+
+TEST(SendableChooserTest, DefaultIsReturnedOnNoSelect) {
+  frc::SendableChooser<int> chooser;
+
+  for (int i = 1; i <= 3; i++) {
+    chooser.AddOption(std::to_string(i), i);
+  }
+
+  // Use 4 here rather than 0 to make sure it's not default-init int.
+  chooser.SetDefaultOption("4", 4);
+
+  EXPECT_EQ(4, chooser.GetSelected());
+}
+
+TEST(SendableChooserTest,
+     DefaultConstructableIsReturnedOnNoSelectAndNoDefault) {
+  frc::SendableChooser<int> chooser;
+
+  for (int i = 1; i <= 3; i++) {
+    chooser.AddOption(std::to_string(i), i);
+  }
+
+  EXPECT_EQ(0, chooser.GetSelected());
+}
+
+INSTANTIATE_TEST_SUITE_P(SendableChooserTests, SendableChooserTest,
+                         ::testing::Values(0, 1, 2, 3));