diff --git a/src/key.php b/src/key.php
index fc3ebe6..b6c9193 100644
--- a/src/key.php
+++ b/src/key.php
@@ -15,5 +15,7 @@
  */
 function key($value, $coll, $default = null)
 {
-    return array_search($value, $coll) ? : $default;
+    $key = array_search($value, $coll);
+
+    return false !== $key ? $key : $default;
 }
diff --git a/tests/KeyTest.php b/tests/KeyTest.php
index 881d669..591455c 100644
--- a/tests/KeyTest.php
+++ b/tests/KeyTest.php
@@ -2,7 +2,6 @@
 
 namespace Lambdish\Phunctional\Tests;
 
-use ArrayIterator;
 use PHPUnit_Framework_TestCase;
 use function Lambdish\Phunctional\key;
 
@@ -31,4 +30,28 @@ public function it_should_return_the_default_value_provided_if_the_key_does_not_
 
         $this->assertSame('three', key(3, $actual, 'three'));
     }
+
+    /** @test */
+    public function it_should_return_empty_string_if_the_key_does_is_empty()
+    {
+        $actual = ['one' => 1, 'two' => 2, '' => 3];
+
+        $this->assertSame('', key(3, $actual, 'default'));
+    }
+
+    /** @test */
+    public function it_should_return_the_value_of_the_item_of_an_existent_boolean_key()
+    {
+        $actual = ['one' => 1, 'two' => false];
+
+        $this->assertSame('two', key(false, $actual, 'default'));
+    }
+
+    /** @test */
+    public function it_should_return_first_occurrence_of_the_item_of_an_existent_key()
+    {
+        $actual = [false => 1];
+
+        $this->assertSame(0, key(1, $actual, 'default'));
+    }
 }