Fix incorrect absolute minimum calculation

Author: klerk1t

src/main/java/com/thealgorithms/maths/AbsoluteMin.java

@@ -1,7 +1,5 @@
 package com.thealgorithms.maths;
 
-import java.util.Arrays;
-
 public final class AbsoluteMin {
     private AbsoluteMin() {
     }
@@ -13,14 +11,16 @@ private AbsoluteMin() {
      * @return The absolute min value
      */
     public static int getMinValue(int... numbers) {
-        if (numbers.length == 0) {
-            throw new IllegalArgumentException("Numbers array cannot be empty");
+        if (numbers == null || numbers.length == 0) {
+            throw new IllegalArgumentException("Numbers array cannot be empty or null");
         }
 
-        var absMinWrapper = new Object() { int value = numbers[0]; };
-
-        Arrays.stream(numbers).skip(1).filter(number -> Math.abs(number) <= Math.abs(absMinWrapper.value)).forEach(number -> absMinWrapper.value = Math.min(absMinWrapper.value, number));
-
-        return absMinWrapper.value;
+        int absMin = numbers[0];
+        for (int i = 1; i < numbers.length; i++) {
+            if (Math.abs(numbers[i]) < Math.abs(absMin) || (Math.abs(numbers[i]) == Math.abs(absMin) && numbers[i] < absMin)) {
+                absMin = numbers[i];
+            }
+        }
+        return absMin;
     }
 }

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

@@ -11,12 +11,16 @@ public class AbsoluteMinTest {
     void testGetMinValue() {
         assertEquals(0, AbsoluteMin.getMinValue(4, 0, 16));
         assertEquals(-2, AbsoluteMin.getMinValue(3, -10, -2));
+        assertEquals(-2, AbsoluteMin.getMinValue(-3, -10, -2));
+        assertEquals(2, AbsoluteMin.getMinValue(-3, -10, 2));
+        assertEquals(2, AbsoluteMin.getMinValue(-5, 2));
+        assertEquals(2, AbsoluteMin.getMinValue(2, -5));
     }
 
     @Test
     void testGetMinValueWithNoArguments() {
-        Exception exception = assertThrows(IllegalArgumentException.class, AbsoluteMin::getMinValue);
-        assertEquals("Numbers array cannot be empty", exception.getMessage());
+        assertThrows(IllegalArgumentException.class, AbsoluteMin::getMinValue);
+        assertThrows(IllegalArgumentException.class, () -> AbsoluteMin.getMinValue((int[]) null));
     }
 
     @Test