Revert "Revert "Add option to check for value presence, while allowing empty values""

This reverts commit 1c62b45.

Author: ilijastuden

src/Validator.php

@@ -34,7 +34,10 @@ public function __construct(
      * Note: strings are trimmed prior to check, and values that empty() would return true for (like '0') are considered
      * to be present (because we check strlen(trim($value))).
      */
-    public function present(string $field_name): bool
+    public function present(
+        string $field_name,
+        bool $allow_empty = false,
+    ): bool
     {
         if (empty($field_name)) {
             throw new InvalidArgumentException(
@@ -46,6 +49,10 @@ public function present(string $field_name): bool
             return $this->failPresenceValidation($field_name);
         }
 
+        if ($allow_empty && empty($this->field_values[$field_name])) {
+            return true;
+        }
+
         if (is_string($this->field_values[$field_name])) {
             if (mb_strlen(trim($this->field_values[$field_name])) > 0) {
                 return true;

test/src/PresenceValidatorTest.php

@@ -42,6 +42,21 @@ public function testPass()
         $this->assertCount(0, $name_errors);
     }
 
+    public function testPassAllowEmpty()
+    {
+        $validator = new Validator($this->connection, 'writers', null, null, ['name' => '']);
+
+        $is_present = $validator->present('name', true);
+
+        $this->assertTrue($is_present);
+        $this->assertFalse($validator->hasErrors());
+
+        $name_errors = $validator->getFieldErrors('name');
+
+        $this->assertIsArray($name_errors);
+        $this->assertCount(0, $name_errors);
+    }
+
     /**
      * Test validation failure.
      */