minor #31677 [Intl] Improve the error message when country code is wrong (javiereguiluz)

This PR was merged into the 4.3 branch.

Discussion
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[Intl] Improve the error message when country code is wrong

| Q             | A
| ------------- | ---
| Branch?       | 4.4
| Bug fix?      | no
| New feature?  | no <!-- please update src/**/CHANGELOG.md files -->
| BC breaks?    | no     <!-- see https://symfony.com/bc -->
| Deprecations? | no <!-- please update UPGRADE-*.md and src/**/CHANGELOG.md files -->
| Tests pass?   | yes    <!-- please add some, will be required by reviewers -->
| Fixed tickets | #31656
| License       | MIT
| Doc PR        | (not needed)

Commits
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f4ff47e47e [Intl] Improve the error message when country code is wrong

src/Symfony/Component/Intl/Tests/TimezonesTest.php

@@ -603,6 +603,15 @@ class TimezonesTest extends ResourceBundleTestCase
         Timezones::forCountryCode('foobar');
     }
 
+    /**
+     * @expectedException \Symfony\Component\Intl\Exception\MissingResourceException
+     * @expectedExceptionMessage Country codes must be in uppercase, but "nl" was passed. Try with "NL" country code instead.
+     */
+    public function testForCountryCodeWithWrongCountryCode()
+    {
+        Timezones::forCountryCode('nl');
+    }
+
     /**
      * @expectedException \Symfony\Component\Intl\Exception\MissingResourceException
      */

src/Symfony/Component/Intl/Timezones.php

@@ -109,6 +109,10 @@ final class Timezones extends ResourceBundle
                 return [];
             }
 
+            if (Countries::exists(strtoupper($country))) {
+                throw new MissingResourceException(sprintf('Country codes must be in uppercase, but "%s" was passed. Try with "%s" country code instead.', $country, strtoupper($country)));
+            }
+
             throw $e;
         }
     }