Update handling of null aggregate values (#43)

Updated methods to handle null values for aggregate calculations by
changing the return type of the getActualAggregate function to '?float',
so that it can now allow null values. This change provides more
flexibility by not forcing a 0 value return when the aggregate
calculation is not possible and aids in better error management and
debugging.

src/Rules/Aggregate/AbstarctAggregateRuleCombo.php

@@ -27,15 +27,17 @@ abstract class AbstarctAggregateRuleCombo extends AbstarctRuleCombo
         self::MAX => ['10.123', ''],
     ];
 
-    abstract protected function getActualAggregate(array $colValues): float;
+    abstract protected function getActualAggregate(array $colValues): ?float;
 
     protected function getActual(array|string $value): float
     {
         if (\is_string($value)) {
             throw new \InvalidArgumentException('The value should be an array of numbers/strings');
         }
 
-        return $this->getActualAggregate($value);
+        $result = $this->getActualAggregate($value);
+
+        return $result ?? 0;
     }
 
     protected function getExpected(): float
@@ -49,7 +51,16 @@ protected function validateComboAggregate(array $colValues, string $mode): ?stri
         $verb   = static::VERBS[$mode];
         $name   = static::NAME;
 
-        $actual   = $this->getActual($colValues);
+        try {
+            $actual = $this->getActualAggregate($colValues); // Important to use the original method here!
+        } catch (\Throwable) {
+            $actual = null;
+        }
+
+        if ($actual === null) {
+            return null; // Looks like it's impossible to calculate the aggregate value in this case. Skip.
+        }
+
         $expected = $this->getExpected();
 
         if (!self::compare($expected, $actual, $mode)) {

src/Rules/Aggregate/ComboAverage.php

@@ -24,12 +24,8 @@ final class ComboAverage extends AbstarctAggregateRuleCombo
 
     protected const HELP_TOP = ['Regular the arithmetic mean. The sum of the numbers divided by the count.'];
 
-    protected function getActualAggregate(array $colValues): float
+    protected function getActualAggregate(array $colValues): ?float
     {
-        try {
-            return Average::mean(self::stringsToFloat($colValues));
-        } catch (\Exception) {
-            return 0;
-        }
+        return Average::mean(self::stringsToFloat($colValues));
     }
 }

src/Rules/Aggregate/ComboCount.php

@@ -32,7 +32,7 @@ final class ComboCount extends AbstarctAggregateRuleCombo
         self::MAX => ['10', ''],
     ];
 
-    protected function getActualAggregate(array $colValues): float
+    protected function getActualAggregate(array $colValues): ?float
     {
         return \count($colValues);
     }

src/Rules/Aggregate/ComboCountEmpty.php

@@ -29,7 +29,7 @@ final class ComboCountEmpty extends AbstarctAggregateRuleCombo
         self::MAX => ['10', ''],
     ];
 
-    protected function getActualAggregate(array $colValues): float
+    protected function getActualAggregate(array $colValues): ?float
     {
         return \count(\array_filter($colValues, static fn ($colValue) => $colValue === ''));
     }

src/Rules/Aggregate/ComboCountNotEmpty.php

@@ -29,7 +29,7 @@ final class ComboCountNotEmpty extends AbstarctAggregateRuleCombo
         self::MAX => ['10', ''],
     ];
 
-    protected function getActualAggregate(array $colValues): float
+    protected function getActualAggregate(array $colValues): ?float
     {
         return \count(\array_filter($colValues, static fn ($colValue) => $colValue !== ''));
     }

src/Rules/Aggregate/ComboMedian.php

@@ -24,12 +24,8 @@ final class ComboMedian extends AbstarctAggregateRuleCombo
 
     protected const HELP_TOP = ['Calculate the median average of a list of numbers.'];
 
-    protected function getActualAggregate(array $colValues): float
+    protected function getActualAggregate(array $colValues): ?float
     {
-        try {
-            return Average::median(self::stringsToFloat($colValues));
-        } catch (\Exception) {
-            return 0;
-        }
+        return Average::median(self::stringsToFloat($colValues));
     }
 }

src/Rules/Aggregate/ComboSum.php

@@ -22,7 +22,7 @@ final class ComboSum extends AbstarctAggregateRuleCombo
 
     protected const HELP_TOP = ['Sum of the numbers in the column. Example: [1, 2, 3] => 6.'];
 
-    protected function getActualAggregate(array $colValues): float
+    protected function getActualAggregate(array $colValues): ?float
     {
         return \array_sum(self::stringsToFloat($colValues));
     }