Fix bug #1626 where values of 0 were "rounded" up/down as if they were not 0 (#1627)

* Fix bug where values of 0 were "rounded" up/down as if they were not 0

CHANGELOG.md

@@ -82,6 +82,7 @@ and this project adheres to [Semantic Versioning](https://semver.org).
 ### Fixed
 
 - PrintArea causes exception [#1544](https://github.com/phpoffice/phpspreadsheet/pull/1544)
+- ROUNDUP and ROUNDDOWN return incorrect results for values of 0 [#1627](https://github.com/phpoffice/phpspreadsheet/pull/1627)
 - Calculation/DateTime Failure With PHP8 [#1661](https://github.com/phpoffice/phpspreadsheet/pull/1661)
 - Reader/Gnumeric Failure with PHP8 [#1662](https://github.com/phpoffice/phpspreadsheet/pull/1662)
 - ReverseSort bug, exposed but not caused by PHP8 [#1660](https://github.com/phpoffice/phpspreadsheet/pull/1660)

src/PhpSpreadsheet/Calculation/MathTrig.php

@@ -1108,6 +1108,10 @@ class MathTrig
         $digits = Functions::flattenSingleValue($digits);
 
         if ((is_numeric($number)) && (is_numeric($digits))) {
+            if ($number == 0.0) {
+                return 0.0;
+            }
+
             if ($number < 0.0) {
                 return round($number - 0.5 * 0.1 ** $digits, $digits, PHP_ROUND_HALF_DOWN);
             }
@@ -1134,6 +1138,10 @@ class MathTrig
         $digits = Functions::flattenSingleValue($digits);
 
         if ((is_numeric($number)) && (is_numeric($digits))) {
+            if ($number == 0.0) {
+                return 0.0;
+            }
+
             if ($number < 0.0) {
                 return round($number + 0.5 * 0.1 ** $digits, $digits, PHP_ROUND_HALF_UP);
             }

tests/data/Calculation/MathTrig/ROUNDDOWN.php

@@ -1,6 +1,11 @@
 <?php
 
 return [
+    [
+        0,
+        0,
+        2,
+    ],
     [
         662,
         662.78999999999996,

tests/data/Calculation/MathTrig/ROUNDUP.php

@@ -1,6 +1,11 @@
 <?php
 
 return [
+    [
+        0,
+        0,
+        2,
+    ],
     [
         663,
         662.78999999999996,