diff --git a/src/Selector.php b/src/Selector.php
index 0b0f671..d025262 100644
--- a/src/Selector.php
+++ b/src/Selector.php
@@ -38,7 +38,7 @@ public function __construct($selector)
      *
      * @return string
      */
-    public function __toString()
+    public function __toString(): string
     {
         return $this->getValue();
     }
@@ -48,7 +48,7 @@ public function __toString()
      *
      * @return string
      */
-    public function getValue()
+    public function getValue(): string
     {
         return $this->selector;
     }
@@ -61,7 +61,7 @@ public function getValue()
      *
      * @return string The flattened attribute array.
      */
-    private function attributeArrayToString($attributes)
+    private function attributeArrayToString($attributes): string
     {
         if (empty($attributes)) {
             throw new AttributeArrayException('Attributes array is empty.');
diff --git a/tests/Unit/SelectorTest.php b/tests/Unit/SelectorTest.php
index 5ce0fc9..3b4edea 100644
--- a/tests/Unit/SelectorTest.php
+++ b/tests/Unit/SelectorTest.php
@@ -28,13 +28,29 @@ public function it_should_accept_string_selectors()
      *
      * @dataProvider provideAttributes
      */
-    public function it_should_automatically_convert_attribute_arrays_to_strings($attributes, $expected)
-    {
+    public function it_should_automatically_convert_attribute_arrays_to_strings(
+        array $attributes,
+        string $expected
+    ) {
         $selector = new Selector($attributes);
 
         $this->assertSame($expected, $selector->getValue());
     }
 
+    /**
+     * @test
+     *
+     * @ticket https://github.com/stevegrunwell/phpunit-markup-assertions/issues/13
+     */
+    public function it_should_be_able_to_handle_spaces_in_attribute_values()
+    {
+        $selector = new Selector([
+            'data-attr' => 'foo bar baz',
+        ]);
+
+        $this->assertSame('*[data-attr="foo bar baz"]', $selector->getValue());
+    }
+
     /**
      * @test
      */
@@ -58,7 +74,7 @@ public function it_should_be_able_to_be_cast_to_a_string()
     /**
      * Data provider for testFlattenAttributeArray().
      *
-     * @return Iterable{array<string, scalar>, string} The attribute array and teh expected string.
+     * @return iterable{array<string, scalar>, string} The attribute array and the expected string.
      */
     public function provideAttributes()
     {