Add midpoint circle algorithm (#5868)

src/test/java/com/thealgorithms/geometry/MidpointCircleTest.java

@@ -0,0 +1,55 @@
+package com.thealgorithms.geometry;
+
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.List;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+
+/**
+ * Test class for the {@code MidpointCircle} class
+ */
+class MidpointCircleTest {
+
+    /**
+     * Parameterized test to check the generated points for different circles.
+     * The points are checked based on the expected center and radius.
+     *
+     * @param centerX The x-coordinate of the circle's center.
+     * @param centerY The y-coordinate of the circle's center.
+     * @param radius  The radius of the circle.
+     */
+    @ParameterizedTest
+    @CsvSource({
+        "0, 0, 3", // Circle centered at (0, 0) with radius 3
+        "10, 10, 2" // Circle centered at (10, 10) with radius 2
+    })
+    void
+    testGenerateCirclePoints(int centerX, int centerY, int radius) {
+        List<int[]> points = MidpointCircle.generateCirclePoints(centerX, centerY, radius);
+
+        // Ensure that all points satisfy the circle equation (x - centerX)^2 + (y - centerY)^2 = radius^2
+        for (int[] point : points) {
+            int x = point[0];
+            int y = point[1];
+
+            int dx = x - centerX;
+            int dy = y - centerY;
+            int distanceSquared = dx * dx + dy * dy;
+
+            assertTrue(Math.abs(distanceSquared - radius * radius) <= 1, "Point (" + x + ", " + y + ") does not satisfy the circle equation.");
+        }
+    }
+
+    /**
+     * Test to ensure the algorithm generates points for a zero-radius circle.
+     */
+    @Test
+    void testZeroRadiusCircle() {
+        List<int[]> points = MidpointCircle.generateCirclePoints(0, 0, 0);
+
+        // A zero-radius circle should only have one point: (0, 0)
+        assertTrue(points.size() == 1 && points.get(0)[0] == 0 && points.get(0)[1] == 0, "Zero-radius circle did not generate the correct point.");
+    }
+}