"""Tests for 2D/3D kinematics calculations."""
from chuk_mcp_physics.kinematics import (
AccelerationFromPositionRequest,
AverageSpeedRequest,
InstantaneousVelocityRequest,
JerkCalculationRequest,
MotionGraphRequest,
TrajectoryFitRequest,
calculate_acceleration_from_position,
calculate_average_speed,
calculate_instantaneous_velocity,
calculate_jerk,
fit_trajectory,
generate_motion_graph,
)
class TestAccelerationFromPosition:
def test_constant_velocity(self):
"""Test constant velocity (zero acceleration)."""
request = AccelerationFromPositionRequest(
times=[0.0, 1.0, 2.0, 3.0],
positions=[[0.0, 0.0, 0.0], [5.0, 0.0, 0.0], [10.0, 0.0, 0.0], [15.0, 0.0, 0.0]],
)
result = calculate_acceleration_from_position(request)
# Velocity should be constant ~5 m/s in x
assert len(result.velocities) == 4
for vel in result.velocities:
assert abs(vel[0] - 5.0) < 0.5 # vx ~5
# Acceleration should be ~0
assert len(result.accelerations) == 4
for acc in result.accelerations:
assert abs(acc[0]) < 0.5 # ax ~0
def test_constant_acceleration(self):
"""Test constant acceleration (x = 0.5*a*t²)."""
# x = 0.5 * 2 * t² = t²
request = AccelerationFromPositionRequest(
times=[0.0, 1.0, 2.0, 3.0, 4.0],
positions=[
[0.0, 0.0, 0.0],
[1.0, 0.0, 0.0],
[4.0, 0.0, 0.0],
[9.0, 0.0, 0.0],
[16.0, 0.0, 0.0],
],
)
result = calculate_acceleration_from_position(request)
# Acceleration should be constant ~2 m/s² (numerical derivative has some error)
for acc in result.accelerations[1:-1]: # Skip edges
assert abs(acc[0] - 2.0) < 0.6 # Relaxed tolerance for numerical derivative
def test_2d_motion(self):
"""Test 2D motion."""
request = AccelerationFromPositionRequest(
times=[0.0, 1.0, 2.0, 3.0],
positions=[
[0.0, 0.0, 0.0],
[3.0, 4.0, 0.0],
[6.0, 8.0, 0.0],
[9.0, 12.0, 0.0],
],
)
result = calculate_acceleration_from_position(request)
assert len(result.velocities) == 4
assert len(result.accelerations) == 4
# Should have constant velocity [3, 4, 0]
for vel in result.velocities:
assert abs(vel[0] - 3.0) < 0.5
assert abs(vel[1] - 4.0) < 0.5
class TestJerkCalculation:
def test_zero_jerk(self):
"""Test zero jerk (constant acceleration)."""
request = JerkCalculationRequest(
times=[0.0, 1.0, 2.0, 3.0],
accelerations=[
[5.0, 0.0, 0.0],
[5.0, 0.0, 0.0],
[5.0, 0.0, 0.0],
[5.0, 0.0, 0.0],
],
)
result = calculate_jerk(request)
# Jerk should be ~0
for jerk in result.jerks:
assert abs(jerk[0]) < 0.1
def test_constant_jerk(self):
"""Test constant jerk (linear acceleration change)."""
request = JerkCalculationRequest(
times=[0.0, 1.0, 2.0, 3.0],
accelerations=[
[0.0, 0.0, 0.0],
[2.0, 0.0, 0.0],
[4.0, 0.0, 0.0],
[6.0, 0.0, 0.0],
],
)
result = calculate_jerk(request)
# Jerk should be constant ~2 m/s³
for jerk in result.jerks[1:-1]: # Skip edges
assert abs(jerk[0] - 2.0) < 0.5
def test_3d_jerk(self):
"""Test jerk in 3D."""
request = JerkCalculationRequest(
times=[0.0, 1.0, 2.0, 3.0],
accelerations=[
[0.0, 0.0, 0.0],
[3.0, 4.0, 0.0],
[6.0, 8.0, 0.0],
[9.0, 12.0, 0.0],
],
)
result = calculate_jerk(request)
# Jerk magnitude should be sqrt(3² + 4²) = 5 m/s³
assert result.max_jerk_magnitude > 4.5
class TestTrajectoryFit:
def test_linear_fit(self):
"""Test linear trajectory fit."""
request = TrajectoryFitRequest(
times=[0.0, 1.0, 2.0, 3.0],
positions=[
[0.0, 1.0, 0.0],
[2.0, 3.0, 0.0],
[4.0, 5.0, 0.0],
[6.0, 7.0, 0.0],
],
fit_type="linear",
)
result = fit_trajectory(request)
# x(t) = 2t, so coefficients should be [0, 2]
assert abs(result.coefficients_x[0]) < 0.1 # Intercept ~0
assert abs(result.coefficients_x[1] - 2.0) < 0.1 # Slope ~2
# y(t) = 1 + 2t, so coefficients should be [1, 2]
assert abs(result.coefficients_y[0] - 1.0) < 0.1 # Intercept ~1
assert abs(result.coefficients_y[1] - 2.0) < 0.1 # Slope ~2
# R² should be perfect
assert result.r_squared > 0.99
def test_quadratic_fit(self):
"""Test quadratic trajectory fit (parabolic motion)."""
request = TrajectoryFitRequest(
times=[0.0, 1.0, 2.0, 3.0],
positions=[
[0.0, 0.0, 0.0],
[1.0, 0.0, 0.0],
[4.0, 0.0, 0.0],
[9.0, 0.0, 0.0],
],
fit_type="quadratic",
)
result = fit_trajectory(request)
# x(t) = t², so coefficients should be [0, 0, 1]
assert abs(result.coefficients_x[0]) < 0.1 # Constant ~0
assert abs(result.coefficients_x[1]) < 0.1 # Linear ~0
assert abs(result.coefficients_x[2] - 1.0) < 0.1 # Quadratic ~1
# R² should be perfect
assert result.r_squared > 0.99
def test_projectile_fit(self):
"""Test fitting projectile motion."""
# Projectile: x = 10t, y = 20t - 5t²
request = TrajectoryFitRequest(
times=[0.0, 1.0, 2.0, 3.0],
positions=[
[0.0, 0.0, 0.0],
[10.0, 15.0, 0.0],
[20.0, 20.0, 0.0],
[30.0, 15.0, 0.0],
],
fit_type="quadratic",
)
result = fit_trajectory(request)
# x(t) = 10t: [0, 10, 0]
assert abs(result.coefficients_x[1] - 10.0) < 0.5
# y(t) = 20t - 5t²: [0, 20, -5]
assert abs(result.coefficients_y[1] - 20.0) < 0.5
assert abs(result.coefficients_y[2] - (-5.0)) < 0.5
assert result.r_squared > 0.99
class TestMotionGraph:
def test_x_component(self):
"""Test motion graph for X component."""
request = MotionGraphRequest(
times=[0.0, 1.0, 2.0, 3.0, 4.0],
positions=[
[0.0, 0.0, 0.0],
[1.0, 0.0, 0.0],
[4.0, 0.0, 0.0],
[9.0, 0.0, 0.0],
[16.0, 0.0, 0.0],
],
component="x",
)
result = generate_motion_graph(request)
assert len(result.times) == 5
assert len(result.positions) == 5
assert len(result.velocities) == 5
assert len(result.accelerations) == 5
assert result.component == "x"
def test_magnitude_component(self):
"""Test motion graph for magnitude."""
request = MotionGraphRequest(
times=[0.0, 1.0, 2.0],
positions=[
[0.0, 0.0, 0.0],
[3.0, 4.0, 0.0],
[6.0, 8.0, 0.0],
],
component="magnitude",
)
result = generate_motion_graph(request)
assert len(result.positions) == 3
# Magnitude should be 5 m (3-4-5 triangle)
assert abs(result.positions[1] - 5.0) < 0.1
class TestAverageSpeed:
def test_straight_line(self):
"""Test average speed on straight line."""
request = AverageSpeedRequest(
positions=[
[0.0, 0.0, 0.0],
[10.0, 0.0, 0.0],
[20.0, 0.0, 0.0],
[30.0, 0.0, 0.0],
],
times=[0.0, 1.0, 2.0, 3.0],
)
result = calculate_average_speed(request)
# Distance = 30 m, time = 3 s, speed = 10 m/s
assert abs(result.average_speed - 10.0) < 0.1
assert abs(result.total_distance - 30.0) < 0.1
assert abs(result.total_time - 3.0) < 0.01
assert abs(result.displacement_magnitude - 30.0) < 0.1
def test_back_and_forth(self):
"""Test path that goes back and forth."""
request = AverageSpeedRequest(
positions=[
[0.0, 0.0, 0.0],
[10.0, 0.0, 0.0],
[0.0, 0.0, 0.0],
],
times=[0.0, 1.0, 2.0],
)
result = calculate_average_speed(request)
# Distance = 20 m (10 + 10), displacement = 0 m
assert abs(result.total_distance - 20.0) < 0.1
assert abs(result.displacement_magnitude) < 0.1
assert abs(result.average_speed - 10.0) < 0.1
def test_3d_path(self):
"""Test 3D path."""
request = AverageSpeedRequest(
positions=[
[0.0, 0.0, 0.0],
[3.0, 4.0, 0.0], # Distance = 5
[6.0, 8.0, 0.0], # Distance = 5
],
times=[0.0, 1.0, 2.0],
)
result = calculate_average_speed(request)
# Total distance = 10 m
assert abs(result.total_distance - 10.0) < 0.1
assert abs(result.average_speed - 5.0) < 0.1
class TestInstantaneousVelocity:
def test_exact_time_match(self):
"""Test velocity at exact time point."""
request = InstantaneousVelocityRequest(
positions=[
[0.0, 0.0, 0.0],
[5.0, 0.0, 0.0],
[10.0, 0.0, 0.0],
],
times=[0.0, 1.0, 2.0],
target_time=1.0,
)
result = calculate_instantaneous_velocity(request)
# Velocity at t=1 should be ~5 m/s
assert abs(result.velocity[0] - 5.0) < 0.5
assert abs(result.speed - 5.0) < 0.5
assert result.interpolated is False
def test_interpolated_velocity(self):
"""Test velocity interpolation."""
request = InstantaneousVelocityRequest(
positions=[
[0.0, 0.0, 0.0],
[10.0, 0.0, 0.0],
[20.0, 0.0, 0.0],
],
times=[0.0, 1.0, 2.0],
target_time=0.5,
)
result = calculate_instantaneous_velocity(request)
# Velocity should be interpolated
assert result.interpolated is True
assert result.speed > 0
def test_2d_velocity(self):
"""Test 2D velocity calculation."""
request = InstantaneousVelocityRequest(
positions=[
[0.0, 0.0, 0.0],
[3.0, 4.0, 0.0],
[6.0, 8.0, 0.0],
],
times=[0.0, 1.0, 2.0],
target_time=1.0,
)
result = calculate_instantaneous_velocity(request)
# Velocity should be [3, 4, 0], speed = 5
assert abs(result.velocity[0] - 3.0) < 0.5
assert abs(result.velocity[1] - 4.0) < 0.5
assert abs(result.speed - 5.0) < 0.5
