obstacle-math: add unit tests for project_distance_on_horizontal_plane function.

src/lib/collision_prevention/CMakeLists.txt

@@ -40,3 +40,4 @@ target_include_directories(CollisionPrevention PUBLIC ${CMAKE_CURRENT_SOURCE_DIR
 target_link_libraries(CollisionPrevention PRIVATE mathlib)
 
 px4_add_functional_gtest(SRC CollisionPreventionTest.cpp LINKLIBS CollisionPrevention)
+px4_add_unit_gtest(SRC ObstacleMathTest.cpp LINKLIBS CollisionPrevention)

src/lib/collision_prevention/ObstacleMathTest.cpp

@@ -0,0 +1,93 @@
+/****************************************************************************
+ *
+ *   Copyright (C) 2025 PX4 Development Team. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name PX4 nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+#include <gtest/gtest.h>
+#include <matrix/math.hpp>
+#include "ObstacleMath.hpp"
+
+using namespace matrix;
+
+TEST(ObstacleMathTest, ProjectDistanceOnHorizontalPlane)
+{
+	// standard vehicle orientation inputs
+	Quatf vehicle_pitch_up_45(Eulerf(0.0f, M_PI_4_F, 0.0f));
+	Quatf vehicle_roll_right_45(Eulerf(M_PI_4_F, 0.0f, 0.0f));
+
+	// GIVEN: a distance, sensor orientation, and quaternion representing the vehicle's orientation
+	float distance = 1.0f;
+	float sensor_orientation = 0; // radians (forward facing)
+
+	// WHEN: we project the distance onto the horizontal plane
+	ObstacleMath::project_distance_on_horizontal_plane(distance, sensor_orientation, vehicle_pitch_up_45);
+
+	// THEN: the distance should be scaled correctly
+	float expected_scale    = sqrtf(2) / 2;
+	float expected_distance = 1.0f * expected_scale;
+
+	EXPECT_NEAR(distance, expected_distance, 1e-5);
+
+	// GIVEN: a distance, sensor orientation, and quaternion representing the vehicle's orientation
+	distance = 1.0f;
+
+	ObstacleMath::project_distance_on_horizontal_plane(distance, sensor_orientation, vehicle_roll_right_45);
+
+	// THEN: the distance should be scaled correctly
+	expected_scale     = 1.f;
+	expected_distance  = 1.0f * expected_scale;
+
+	EXPECT_NEAR(distance, expected_distance, 1e-5);
+
+	// GIVEN: a distance, sensor orientation, and quaternion representing the vehicle's orientation
+	distance = 1.0f;
+	sensor_orientation = M_PI_2_F; // radians (right facing)
+
+	ObstacleMath::project_distance_on_horizontal_plane(distance, sensor_orientation, vehicle_roll_right_45);
+
+	// THEN: the distance should be scaled correctly
+	expected_scale     = sqrtf(2) / 2;
+	expected_distance  = 1.0f * expected_scale;
+
+	EXPECT_NEAR(distance, expected_distance, 1e-5);
+
+	// GIVEN: a distance, sensor orientation, and quaternion representing the vehicle's orientation
+	distance = 1.0f;
+
+	ObstacleMath::project_distance_on_horizontal_plane(distance, sensor_orientation, vehicle_pitch_up_45);
+
+	// THEN: the distance should be scaled correctly
+	expected_scale     = 1.f;
+	expected_distance  = 1.0f * expected_scale;
+
+	EXPECT_NEAR(distance, expected_distance, 1e-5);
+
+}