Add More Tests (#4148)

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

@@ -0,0 +1,36 @@
+package com.thealgorithms.maths;
+
+import org.junit.jupiter.api.Test;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class MedianTest {
+    @Test
+    void medianSingleValue() {
+        int[] arr = {0};
+        assertEquals(0, Median.median(arr));
+    }
+
+    @Test
+    void medianTwoValues() {
+        int[] arr = {1, 2};
+        assertEquals(1.5, Median.median(arr));
+    }
+
+    @Test
+    void medianThreeValues() {
+        int[] arr = {1, 2, 3};
+        assertEquals(2, Median.median(arr));
+    }
+
+    @Test
+    void medianDecimalValueReturn() {
+        int[] arr = {1, 2, 3, 4, 5, 6, 8, 9};
+        assertEquals(4.5, Median.median(arr));
+    }
+
+    @Test
+    void medianNegativeValues() {
+        int[] arr = {-27, -16, -7, -4, -2, -1};
+        assertEquals(-5.5, Median.median(arr));
+    }
+}