Support filtering timezones by country code (#480)

Author: aprat84

Diff for: src/Faker/Core/DateTime.php

@@ -217,8 +217,14 @@ public function century(): string
         return Helper::randomElement($this->centuries);
     }
 
-    public function timezone(): string
+    public function timezone(string $countryCode = null): string
     {
-        return Helper::randomElement(\DateTimeZone::listIdentifiers());
+        if ($countryCode) {
+            $timezones = \DateTimeZone::listIdentifiers(\DateTimeZone::PER_COUNTRY, $countryCode);
+        } else {
+            $timezones = \DateTimeZone::listIdentifiers();
+        }
+
+        return Helper::randomElement($timezones);
     }
 }

Diff for: src/Faker/Extension/DateTimeExtension.php

@@ -234,7 +234,9 @@ public function century(): string;
     /**
      * Get a random timezone, uses `\DateTimeZone::listIdentifiers()` internally.
      *
+     * @param string|null $countryCode two-letter ISO 3166-1 compatible country code
+     *
      * @example 'Europe/Rome'
      */
-    public function timezone(): string;
+    public function timezone(string $countryCode = null): string;
 }

Diff for: src/Faker/Generator.php

@@ -255,7 +255,7 @@
  *
  * @property string $timezone
  *
- * @method string timezone()
+ * @method string timezone($countryCode = null)
  *
  * @property void $setDefaultTimezone
  *

Diff for: test/Faker/Core/DateTimeTest.php

@@ -221,8 +221,11 @@ public function testCentury()
     public function testTimezone()
     {
         $timezone = $this->extension->timezone();
+        $countryTimezone = $this->extension->timezone('US');
 
         self::assertIsString($timezone);
         self::assertContains($timezone, \DateTimeZone::listIdentifiers());
+        self::assertIsString($countryTimezone);
+        self::assertContains($countryTimezone, \DateTimeZone::listIdentifiers(\DateTimeZone::PER_COUNTRY, 'US'));
     }
 }