add tests for body implementation; slightly edit body.cpp implementation

src/body.cpp

@@ -12,4 +12,4 @@ float DENSITY = 4E3;
 
 // Constructor definition
 Body::Body(const std::array<double, 3>* initial_position, const std::array<double, 3>* initial_velocity, double mass, float radius)
-    : Particle(initial_position, initial_velocity, mass), radius(radius == 0 ? pow(3 * mass / (4 * M_PI * DENSITY), 1/3) : radius) {};
+    : Particle(initial_position, initial_velocity, mass), radius((radius == 0) ? pow(3 * mass / (4 * M_PI * DENSITY), 1./3.) : radius) {};

test/test_body.cpp

@@ -0,0 +1,67 @@
+#define _USE_MATH_DEFINES
+
+#include <array>
+#include <cmath>
+
+#include "../include/doctest.h" 
+#include "../include/body.h"
+
+TEST_CASE("Body Initialization - WITH Radius") {
+
+    // Initialize particle specs
+    double mass = 1;
+    std::array<double, 3> initial_position1 = {0, 0, 0};
+    std::array<double, 3> initial_velocity1 = {0, 0, 0};
+    float radius = 1E5;
+
+    // Define the particle
+    Body body1(&initial_position1, &initial_velocity1, mass, radius);
+
+    CHECK(body1.position[0] == 0);
+    CHECK(body1.position[1] == 0);
+    CHECK(body1.position[2] == 0);
+    CHECK(body1.mass == 1);
+    CHECK(body1.radius == 1E5);
+}
+
+TEST_CASE("Body Initialization - WITHOUT Radius") {
+
+    // Initialize particle specs
+    double mass = 1;
+    std::array<double, 3> initial_position1 = {0, 0, 0};
+    std::array<double, 3> initial_velocity1 = {0, 0, 0};
+
+    // Define the particle
+    Body body1(&initial_position1, &initial_velocity1, mass);
+
+    CHECK(body1.position[0] == 0);
+    CHECK(body1.position[1] == 0);
+    CHECK(body1.position[2] == 0);
+    CHECK(body1.mass == 1);
+    CHECK((body1.radius - pow(3 * mass / (4 * M_PI * 4E3), 1./3.)) < 0.000001);
+}
+
+
+TEST_CASE("Body Update") {
+
+    // Parameters for a timestep
+    double timestep = 1;
+
+    // Initialize particle specs
+    double mass = 1;
+    float radius = 1E5;
+    std::array<double, 3> initial_position1 = {0, 0, 0};
+    std::array<double, 3> initial_velocity1 = {0, 0, 0};
+
+    // Define the force
+    std::array<double, 3> force = {3, 0, 0};
+
+    // Define the particle
+    Body body1(&initial_position1, &initial_velocity1, mass, radius);
+
+    // Update particle
+    body1.update(&force, timestep);
+
+    // Check the update works
+    CHECK(body1.position[0] == 1.5);
+}