[examples] AddressableLED: Add unit test (#4779)

wpilibcExamples/src/main/cpp/examples/AddressableLED/cpp/Robot.cpp

@@ -2,54 +2,37 @@
 // 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 <array>
+#include "Robot.h"
 
-#include <frc/AddressableLED.h>
-#include <frc/TimedRobot.h>
-#include <frc/smartdashboard/SmartDashboard.h>
+void Robot::RobotInit() {
+  // Default to a length of 60, start empty output
+  // Length is expensive to set, so only set it once, then just update data
+  m_led.SetLength(kLength);
+  m_led.SetData(m_ledBuffer);
+  m_led.Start();
+}
 
-class Robot : public frc::TimedRobot {
-  static constexpr int kLength = 60;
+void Robot::RobotPeriodic() {
+  // Fill the buffer with a rainbow
+  Rainbow();
+  // Set the LEDs
+  m_led.SetData(m_ledBuffer);
+}
 
-  // PWM port 9
-  // Must be a PWM header, not MXP or DIO
-  frc::AddressableLED m_led{9};
-  std::array<frc::AddressableLED::LEDData, kLength>
-      m_ledBuffer;  // Reuse the buffer
-  // Store what the last hue of the first pixel is
-  int firstPixelHue = 0;
-
- public:
-  void Rainbow() {
-    // For every pixel
-    for (int i = 0; i < kLength; i++) {
-      // Calculate the hue - hue is easier for rainbows because the color
-      // shape is a circle so only one value needs to precess
-      const auto pixelHue = (firstPixelHue + (i * 180 / kLength)) % 180;
-      // Set the value
-      m_ledBuffer[i].SetHSV(pixelHue, 255, 128);
-    }
-    // Increase by to make the rainbow "move"
-    firstPixelHue += 3;
-    // Check bounds
-    firstPixelHue %= 180;
+void Robot::Rainbow() {
+  // For every pixel
+  for (int i = 0; i < kLength; i++) {
+    // Calculate the hue - hue is easier for rainbows because the color
+    // shape is a circle so only one value needs to precess
+    const auto pixelHue = (firstPixelHue + (i * 180 / kLength)) % 180;
+    // Set the value
+    m_ledBuffer[i].SetHSV(pixelHue, 255, 128);
   }
-
-  void RobotInit() override {
-    // Default to a length of 60, start empty output
-    // Length is expensive to set, so only set it once, then just update data
-    m_led.SetLength(kLength);
-    m_led.SetData(m_ledBuffer);
-    m_led.Start();
-  }
-
-  void RobotPeriodic() override {
-    // Fill the buffer with a rainbow
-    Rainbow();
-    // Set the LEDs
-    m_led.SetData(m_ledBuffer);
-  }
-};
+  // Increase by to make the rainbow "move"
+  firstPixelHue += 3;
+  // Check bounds
+  firstPixelHue %= 180;
+}
 
 #ifndef RUNNING_FRC_TESTS
 int main() {

wpilibcExamples/src/main/cpp/examples/AddressableLED/include/Robot.h

@@ -0,0 +1,28 @@
+// 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.
+
+#pragma once
+
+#include <array>
+
+#include <frc/AddressableLED.h>
+#include <frc/TimedRobot.h>
+
+class Robot : public frc::TimedRobot {
+ public:
+  void Rainbow();
+  void RobotInit() override;
+  void RobotPeriodic() override;
+
+ private:
+  static constexpr int kLength = 60;
+
+  // PWM port 9
+  // Must be a PWM header, not MXP or DIO
+  frc::AddressableLED m_led{9};
+  std::array<frc::AddressableLED::LEDData, kLength>
+      m_ledBuffer;  // Reuse the buffer
+  // Store what the last hue of the first pixel is
+  int firstPixelHue = 0;
+};

wpilibcExamples/src/test/cpp/examples/AddressableLED/cpp/RainbowTest.cpp

@@ -0,0 +1,53 @@
+// 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 <fmt/format.h>
+#include <gtest/gtest.h>
+
+#include <array>
+
+#include <frc/AddressableLED.h>
+#include <frc/simulation/AddressableLEDSim.h>
+#include <frc/util/Color.h>
+#include <frc/util/Color8Bit.h>
+#include <hal/AddressableLEDTypes.h>
+
+#include "Robot.h"
+
+void AssertIndexColor(std::array<frc::AddressableLED::LEDData, 60> data,
+                      int index, int hue, int saturation, int value);
+
+TEST(RainbowTest, RainbowPattern) {
+  Robot robot;
+  robot.RobotInit();
+  frc::sim::AddressableLEDSim ledSim =
+      frc::sim::AddressableLEDSim::CreateForChannel(9);
+  EXPECT_TRUE(ledSim.GetRunning());
+  EXPECT_EQ(60, ledSim.GetLength());
+
+  auto rainbowFirstPixelHue = 0;
+  std::array<frc::AddressableLED::LEDData, 60> data;
+  for (int iteration = 0; iteration < 100; iteration++) {
+    SCOPED_TRACE(fmt::format("Iteration {} of 100", iteration));
+    robot.RobotPeriodic();
+    ledSim.GetData(data.data());
+    for (int i = 0; i < 60; i++) {
+      SCOPED_TRACE(fmt::format("LED {} of 60", i));
+      auto hue = (rainbowFirstPixelHue + (i * 180 / 60)) % 180;
+      AssertIndexColor(data, i, hue, 255, 128);
+    }
+    rainbowFirstPixelHue += 3;
+    rainbowFirstPixelHue %= 180;
+  }
+}
+
+void AssertIndexColor(std::array<frc::AddressableLED::LEDData, 60> data,
+                      int index, int hue, int saturation, int value) {
+  frc::Color8Bit color{frc::Color::FromHSV(hue, saturation, value)};
+
+  EXPECT_EQ(0, data[index].padding);
+  EXPECT_EQ(color.red, data[index].r & 0xFF);
+  EXPECT_EQ(color.green, data[index].g & 0xFF);
+  EXPECT_EQ(color.blue, data[index].b & 0xFF);
+}

wpilibcExamples/src/test/cpp/examples/AddressableLED/cpp/main.cpp

@@ -0,0 +1,17 @@
+// 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 <hal/HALBase.h>
+
+#include "gtest/gtest.h"
+
+/**
+ * Runs all unit tests.
+ */
+int main(int argc, char** argv) {
+  HAL_Initialize(500, 0);
+  ::testing::InitGoogleTest(&argc, argv);
+  int ret = RUN_ALL_TESTS();
+  return ret;
+}