Fix test file package and project structure

Author: Gopesh111

src/test/java/com/thealgorithms/maths/DistanceBetweenTwoPointsTest.java

@@ -0,0 +1,35 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+class DistanceBetweenTwoPointsTest {
+
+    @Test
+    void testDistanceSimple() {
+        assertEquals(
+                5.0,
+                DistanceBetweenTwoPoints.calculate(0, 0, 3, 4),
+                1e-9
+        );
+    }
+
+    @Test
+    void testDistanceNegativeCoordinates() {
+        assertEquals(
+                5.0,
+                DistanceBetweenTwoPoints.calculate(-1, -1, 2, 3),
+                1e-9
+        );
+    }
+
+    @Test
+    void testSamePoint() {
+        assertEquals(
+                0.0,
+                DistanceBetweenTwoPoints.calculate(2, 2, 2, 2),
+                1e-9
+        );
+    }
+}