Fix for issue #2 (#3)

* Adding failing test for #2 TDD

* Fix for #2

src/Confusable.php

@@ -143,7 +143,9 @@ public function isConfusable(string $string, bool $greedy = false, array $prefer
                 continue;
             }
 
-            $found = $this->confusablesData[$char];
+            // The original source uses the Python dictionary get() method which returns a default
+            // if the key doesn't exist in the dictionary. This solves issue #2.
+            $found = isset($this->confusablesData[$char]) ? $this->confusablesData[$char] : [];
             // Character λ is considered confusable if λ can be confused with a character from
             // $preferredAliases, e.g. if 'LATIN', 'ρ' is confusable with 'p' from LATIN.
             // if 'LATIN', 'Γ' is not confusable because in all the characters confusable with Γ,

tests/ConfusableTest.php

@@ -67,6 +67,16 @@ public function testIsConfusable()
         // For 'Greek' readers, p is confusable!  ↓
         $confusable = $confusables->isConfusable('paρa', false, ['greek'])[0]['character'];
         $this->assertEquals('p', $confusable);
+
+        // Microsoft contains a zero width character - added for #2
+        $this->assertTrue(is_array($confusables->isConfusable('www.microsоft.com')));
+        $this->assertTrue(is_array($confusables->isConfusable('www.Αpple.com')));
+        $this->assertTrue(is_array($confusables->isConfusable('www.faϲebook.com')));
+
+        // The three below are all not confusable - added for #2
+        $this->assertFalse(is_array($confusables->isConfusable('www.microsoft.com', false, ['latin'])));
+        $this->assertFalse(is_array($confusables->isConfusable('www.apple.com', false, ['latin'])));
+        $this->assertFalse(is_array($confusables->isConfusable('www.facebook.com', false, ['latin'])));
     }
 
     public function testIsDangerous()