ros2-assignments/doc/tests/Simulator.md

Simulator Unit Tests

Unit tests for the Simulator class are implemented in src/g2_2025_odometry_pkg/test/test_simulator.cpp using Google Test and ROS2 test utilities. The tests validate interval-based value generation with different interpolation types.

Test Cases

1. ConstantInterval

Description: Verifies constant interpolation returns the same value throughout the interval.

• Test Configuration:
  • Single interval: t=[0, 10], y_start=5.0
  • Type: constant
• Expected Result:
  • Value is 5.0 at t=0, t=5, t=10
  • Value holds at 5.0 after interval (t=15)

2. LinearInterval

Description: Tests linear interpolation between start and end values.

• Test Configuration:
  • Single interval: t=[0, 10], y_start=0.0, y_end=10.0
  • Type: linear
• Expected Result:
  • Value is 0.0 at t=0
  • Value is 5.0 at t=5
  • Value is 10.0 at t=10
  • Value holds at 10.0 after interval (t=15)

3. QuadraticInterval

Description: Tests quadratic (Lagrange) interpolation through 3 points.

• Test Configuration:
  • Single interval: t=[0, 10], y_start=0.0, y_end=0.0, t_mid=5.0, y_mid=10.0
  • Type: quadratic
• Expected Result:
  • Value is 0.0 at t=0
  • Value is 10.0 at t=5 (peak)
  • Value is 0.0 at t=10
  • Value holds at 0.0 after interval (t=15)

4. MultipleIntervals

Description: Tests behavior with multiple non-overlapping intervals and gaps.

• Test Configuration:
  • Interval 0: t=[0, 5], constant 5.0
  • Interval 1: t=[10, 15], constant 10.0
  • Gap between t=5 and t=10
• Expected Result:
  • Value is 5.0 at t=2.5 (first interval)
  • Value holds at 5.0 in gap (t=7.5)
  • Value is 10.0 at t=12.5 (second interval)
  • Value holds at 10.0 after all intervals (t=20)

5. ValueBeforeIntervals

Description: Tests behavior when querying time before any interval starts.

• Test Configuration:
  • Single interval: t=[10, 20]
• Expected Result:
  • Value is 0.0 at t=5 (before interval starts)

6. NonExistentChannel

Description: Tests graceful handling of queries for unconfigured channels.

• Test Action: Query get_object_value("nonexistent_channel", 5.0)
• Expected Result: Returns 0.0

7. OverlappingIntervalsThrowsException

Description: Verifies that overlapping intervals are detected and rejected.

• Test Configuration:
  • Interval 0: t=[0, 10]
  • Interval 1: t=[5, 15] (overlaps)
• Expected Result: Constructor throws std::runtime_error

8. MaxIntervalsLimit

Description: Tests that max_intervals parameter limits loaded intervals.

• Test Configuration:
  • max_intervals=2
  • num_intervals=3 (defines 3 intervals)
• Expected Result:
  • Only first 2 intervals are loaded
  • Third interval values default to holding second interval's end value

Test Infrastructure

The test class SimulatorTest provides:

• Static SetUpTestSuite() and TearDownTestSuite() for ROS2 init/shutdown
• Helper method createNodeWithParams() for creating nodes with parameter overrides