ros2-assignments/doc/tests/WheelDataSimulator.md

Wheel Data Simulator Unit Tests

Unit tests for the DataSimulator (Wheel) node are implemented in src/g2_2025_odometry_pkg/test/test_wheel_simulator.cpp using Google Test and ROS2 test utilities. The tests validate node initialization, message publishing, array structure, and data correctness.

Test Cases

1. NodeInitialization

Description: Verifies that the Wheel DataSimulator node can be created without errors.

• Test Action: Create DataSimulator instance
• Expected Result: No exceptions thrown during construction

2. WheelDataPublishing

Description: Tests that wheel data messages are published on the correct topic.

• Test Action:
  • Create subscription to simulated_wheel_data topic
  • Create DataSimulator node
  • Spin both nodes for a short period
• Expected Result: At least one std_msgs/msg/Float64MultiArray message is received

3. WheelDataArraySize

Description: Verifies that the published array contains the correct number of wheel values.

• Test Action:
  • Subscribe to simulated_wheel_data
  • Receive a message
  • Check array size
• Expected Result: data.size() equals 4 (FL, FR, RL, RR)

4. ValidVelocityValues

Description: Tests that all wheel velocity values are valid (finite numbers).

• Test Action:
  • Subscribe and receive wheel data message
  • Check each value in the array
• Expected Result: All 4 values are finite numbers

5. MultipleMessagesReceived

Description: Tests that multiple messages are published over time.

• Test Action:
  • Subscribe and count received messages
  • Spin for a short duration
• Expected Result: Message count is greater than 0

Test Infrastructure

The test class WheelSimulatorTest provides:

• Static SetUpTestSuite() and TearDownTestSuite() for ROS2 init/shutdown
• Helper method setupBasicWheelParams() for setting up default test parameters

ROS2 Topics Used

Topic	Message Type	Direction
simulated_wheel_data	std_msgs/msg/Float64MultiArray	Published by node under test

Data Array Format

The published Float64MultiArray contains wheel values in the following order:

Index	Wheel
0	Front Left (FL)
1	Front Right (FR)
2	Rear Left (RL)
3	Rear Right (RR)