spec: fix selinimum capture autoload issue, fixes SD-2103

fix a newly exposed autoloading edge case, that depends on spec run order.
given:

ConversationParticipant which autoloads:
  SimpleTags and
  Conversation (which would normally autoload SimpleTags),

when we reset autoloads and then resolve Conversation, ensure it restore
SimpleTags

also remove a weird self-require_dependency ... it's not a problem for AS,
but it is for selinimum

[ci selinimum capture]

test plan:
n/a, specs

Change-Id: I6b0193c9162a70554c997f4ed0c76690c86bf0e0
Reviewed-on: https://gerrit.instructure.com/102628
Tested-by: Jenkins
Reviewed-by: Landon Wilkins <lwilkins@instructure.com>
Product-Review: Landon Wilkins <lwilkins@instructure.com>
QA-Review: Landon Wilkins <lwilkins@instructure.com>

app/models/quizzes/quiz_question/user_answer.rb

@@ -77,4 +77,4 @@ class Quizzes::QuizQuestion::UserAnswer < Struct.new(:question_id, :points_possi
   end
 end
 
-Dir[Rails.root + "app/models/quizzes/quiz_question/*_answer.rb"].each { |f| require_dependency f }
+(Dir[Rails.root + "app/models/quizzes/quiz_question/*_answer.rb"] - [__FILE__]).each { |f| require_dependency f }

gems/selinimum/lib/selinimum/capture/autoload_extensions.rb

@@ -90,31 +90,23 @@ module Selinimum
         # whenever we first autoload something, keep track of what it
         # autoloads. returns an array of file paths
         def track_dependencies(const_names)
-          nested = !dependencies_stack.empty?
-
           dependencies_stack << []
-
-          if nested
-            # top-most track_dependencies call has us covered wrt resetting
-            yield
-          else
-            # this is a top-level autoload (e.g. the top-most `Foo` in the
-            # stack). to really know what this thing depends on, we need to
-            # reset autoloaded stuff yet again, so we don't get freeloaders
-            # from a previous autoload.
-            #
-            # note that we exempt nesting names, since we want to make sure
-            # we don't create dummy duplicate modules/classes (either due to
-            # redundant definitions, or rails' automatic module-from-
-            # directories), e.g.:
-            #
-            #   # foo/bar/baz.rb
-            #   class Foo::Bar # <- we want Baz to be the previously
-            #     class Baz    #    autoloaded class, not a new one
-            #       ...
-            nesting_names = const_names.map { |c| nesting_names_for(c) }.flatten
-            temporarily_reset_autoloads(nesting_names) { yield }
-          end
+          # when we auto-load something, to really know what it depends on,
+          # we need to reset autoloaded stuff, so we don't get freeloaders
+          # from a previous autoload. this is true both for top-level
+          # autoloads as well as for ones triggered by them.
+          #
+          # note that we exempt nesting names, since we want to make sure
+          # we don't create dummy duplicate modules/classes (either due to
+          # redundant definitions, or rails' automatic module-from-
+          # directories), e.g.:
+          #
+          #   # foo/bar/baz.rb
+          #   class Foo::Bar # <- we want Baz to be the previously
+          #     class Baz    #    autoloaded class, not a new one
+          #       ...
+          nesting_names = const_names.map { |c| nesting_names_for(c) }.flatten
+          temporarily_reset_autoloads(nesting_names) { yield }
           current_dependencies
         ensure
           dependencies_stack.pop

gems/selinimum/spec/selinimum/capture/autoload_extensions_spec.rb

@@ -27,7 +27,7 @@ describe Selinimum::Capture::AutoloadExtensions do
       end
 
       context "dependency tracking" do
-        it "temporarily resets other top-level autoloads" do
+        it "temporarily resets top-level sibling autoloads" do
           cache_constants("SelinimumFoo") do
             SelinimumFoo = Class.new
           end
@@ -41,17 +41,40 @@ describe Selinimum::Capture::AutoloadExtensions do
           expect(Object.const_defined?("SelinimumBar")).to be true
         end
 
-        it "doesn't reset nested autoloads" do
-          cache_constants("SelinimumFoo") do
-            SelinimumFoo = Class.new
+        it "temporarily resets nested sibling autoloads" do
+          cache_constants("SelinimumTopLevel") do
+            SelinimumTopLevel = Class.new
+
+            cache_constants("SelinimumFoo") do
+              SelinimumFoo = Class.new
+            end
 
             cache_constants("SelinimumBar") do
-              expect(Object.const_defined?("SelinimumFoo")).to be true
+              expect(Object.const_defined?("SelinimumFoo")).to be false
               SelinimumBar = Class.new
             end
+            expect(Object.const_defined?("SelinimumFoo")).to be true
+            expect(Object.const_defined?("SelinimumBar")).to be true
           end
         end
 
+        # this will require some refactoring...
+        it "temporarily resets outer autoloads" do
+          pending "not implemented"
+
+          cache_constants("SelinimumFoo") do
+            SelinimumTopLevel = Class.new
+
+            cache_constants("SelinimumBar") do
+              expect(Object.const_defined?("SelinimumFoo")).to be false
+              SelinimumFoo = Class.new
+            end
+          end
+
+          expect(Object.const_defined?("SelinimumFoo")).to be true
+          expect(Object.const_defined?("SelinimumBar")).to be true
+        end
+
         it "doesn't reset autoloads from surrounding modules" do
           cache_constants("SelinimumFoo") do
             SelinimumFoo = Class.new
@@ -71,7 +94,6 @@ describe Selinimum::Capture::AutoloadExtensions do
             SelinimumFoo = Class.new
 
             cache_constants("SelinimumBar") do
-              expect(Object.const_defined?("SelinimumFoo")).to be true
               SelinimumBar = Class.new
             end
           end