Testing changes

Test from the safest, cheapest check to the most realistic one: static checks, simulation or hardware-free tests, controlled subsystem tests, full-robot tests, and practice.

Use the WPILib Command Palette in WPILib VS Code for normal team work. Build Robot Code is the compile check, Simulate Robot Code runs the desktop simulator, and Deploy Robot Code sends the program to the roboRIO after the hardware test is approved.

Before enabling

• State the expected behavior and stop condition.
• Keep the test physically bounded.
• Assign one person to enable and disable.
• Make relevant telemetry visible.
• Confirm everyone nearby understands the test.

Use a test ladder

Move to the next level only after the current one produces the expected evidence.

Level	Example	What it proves
Static	Run WPILib: Build Robot Code, format, inspect configuration	The project is internally consistent
Unit	Test a conversion or decision rule	Logic works for known inputs
Simulation	Run WPILib: Simulate Robot Code	Commands and state changes interact correctly
Bench	Move one actuator at limited output	Wiring, signs, sensors, and basic control are correct
Integrated	Run WPILib: Deploy Robot Code, then test connected systems	Boundaries and interlocks work together
Practice	Repeat a realistic cycle	Timing, usability, and reliability hold under load

Test behavior at the boundary

Prefer tests against a public system contract. This keeps them useful when vendor hardware or internal implementation changes.

@Test
void blocksExtensionWhenPivotIsUnsafe() {
  FakePivotIO pivotIO = new FakePivotIO();
  FakeElevatorIO elevatorIO = new FakeElevatorIO();
  Superstructure superstructure = new Superstructure(pivotIO, elevatorIO);

  pivotIO.positionRad = 0.10;
  superstructure.requestHighScore();
  superstructure.periodic();

  assertEquals(0.0, elevatorIO.commandedVolts, 1e-9);
  assertEquals(BlockReason.PIVOT_NOT_CLEAR, superstructure.blockReason());
}

This test checks a safety rule and its explanation. It does not depend on a motor-controller library.

Include failure cases

• Sensor disconnected or returning an invalid value
• Command interrupted halfway through motion
• Goal outside the configured range
• Timeout before completion
• Robot disabled and re-enabled
• Two systems requesting conflicting states
• Data arriving late or out of order

Record the test

Use a short test note with enough detail for another person to repeat it:

Change: Updated elevator homing timeout
Setup: Robot on blocks, carriage below midpoint, fresh battery
Expected: Motor moves down at 1.5 V and stops at switch within 2 s
Observed: Stopped at 1.18 s; state changed HOMING → READY
Evidence: log_2026-09-12_1423.wpilog
Remaining: Repeat after full practice cycle

After the test

Capture the result while it is fresh. Record failures as observations before proposing causes.