fix: CompoundSelector#child_nodes should not include nil type

Author: flavorjones

lib/syntax_tree/css/selectors.rb

@@ -125,7 +125,7 @@ def accept(visitor)
         end
 
         def child_nodes
-          [type, subclasses, pseudo_elements].flatten
+          [type, subclasses, pseudo_elements].compact.flatten
         end
 
         alias deconstruct child_nodes

test/selectors_test.rb

@@ -27,6 +27,15 @@ class SelectorsTest < Minitest::Spec
               ]
             ]
           end
+
+          assert_pattern do
+            actual => [
+              Selectors::CompoundSelector[
+                Selectors::ClassSelector[value: { value: "flex" }],
+                Selectors::ClassSelector[value: { value: "text-xl" }]
+              ]
+            ]
+          end
         end
 
         it "parses a compound selector" do
@@ -41,6 +50,15 @@ class SelectorsTest < Minitest::Spec
               ]
             ]
           end
+
+          assert_pattern do
+            actual => [
+              Selectors::CompoundSelector[
+                Selectors::TypeSelector[value: { name: { value: "div" } } ],
+                Selectors::ClassSelector[value: { value: "flex" }],
+              ]
+            ]
+          end
         end
 
         it "parses a compound selector with a pseudo-element" do