Convert tag label to lowercase in RuleBasedTagger

Fixes #4266

Signed-off-by: Kevin Decherf <kevin@kdecherf.com>

src/Wallabag/CoreBundle/Helper/RuleBasedTagger.php

@@ -94,6 +94,7 @@ class RuleBasedTagger
      */
     private function getTag($label)
     {
+        $label = mb_convert_case($label, \MB_CASE_LOWER);
         $tag = $this->tagRepository->findOneByLabel($label);
 
         if (!$tag) {

tests/Wallabag/CoreBundle/Helper/RuleBasedTaggerTest.php

@@ -139,6 +139,37 @@ class RuleBasedTaggerTest extends TestCase
         $this->assertCount(1, $records);
     }
 
+    public function testWithMixedCaseTag()
+    {
+        $taggingRule = $this->getTaggingRule('rule as string', ['Foo']);
+        $user = $this->getUser([$taggingRule]);
+        $entry = new Entry($user);
+        $tag = new Tag();
+
+        $this->rulerz
+            ->expects($this->once())
+            ->method('satisfies')
+            ->with($entry, 'rule as string')
+            ->willReturn(true);
+
+        $this->tagRepository
+            ->expects($this->once())
+            // the method `findOneByLabel` doesn't exist, EntityRepository will then call `_call` method
+            // to magically call the `findOneBy` with ['label' => 'foo']
+            ->method('__call')
+            ->with('findOneByLabel', ['foo'])
+            ->willReturn($tag);
+
+        $this->tagger->tag($entry);
+
+        $this->assertFalse($entry->getTags()->isEmpty());
+
+        $tags = $entry->getTags();
+        $this->assertSame($tag, $tags[0]);
+        $records = $this->handler->getRecords();
+        $this->assertCount(1, $records);
+    }
+
     public function testSameTagWithDifferentfMatchingRules()
     {
         $taggingRule = $this->getTaggingRule('bla bla', ['hey']);