A::random(): exception if $count exceeds array

Fixes #5934

src/Toolkit/A.php

@@ -738,12 +738,18 @@ public static function nestByKeys($value, array $keys)
 	/**
 	 * Returns a number of random elements from an array,
 	 * either in original or shuffled order
+	 *
+	 * @throws \Exception When $count is larger than array length
 	 */
 	public static function random(
 		array $array,
 		int $count = 1,
 		bool $shuffle = false
 	): array {
+		if ($count > count($array)) {
+			throw new Exception('$count is larger than available array items');
+		}
+
 		if ($shuffle === true) {
 			return array_slice(self::shuffle($array), 0, $count);
 		}

tests/Toolkit/ATest.php

@@ -697,6 +697,16 @@ public function testRandom()
 		}
 	}
 
+	/**
+	 * @covers ::random
+	 */
+	public function testRandomInvalidCount()
+	{
+		$this->expectException(Exception::class);
+		$this->expectExceptionMessage('$count is larger than available array items');
+		A::random([1,2,3], 4);
+	}
+
 	/**
 	 * @covers ::fill
 	 */