fix(test): wrap flaky homepage tests in travel_to blocks

Fix time-dependent flaky tests by wrapping scenarios in travel_to blocks.

The issue was that fabricator timestamps are evaluated at file load time,
while the upcoming scope compares against Time.zone.now at query time.
When time passes between fixture creation and page visit, events may be
filtered out incorrectly.

This follows the same pattern as commit 3f44835 which fixed similar
flaky tests in other files.

Author: mroderick

spec/features/visiting_homepage_spec.rb

@@ -2,7 +2,7 @@
   let!(:next_workshop) { Fabricate(:workshop) }
   let!(:events) { Fabricate.times(3, :event) }
 
-  before(:each) do
+  before do
     visit root_path
   end
 
@@ -11,11 +11,15 @@
   end
 
   scenario 'i can view the next workshop' do
-    expect(page).to have_content "Workshop at #{next_workshop.host.name}"
+    travel_to(Time.current) do
+      expect(page).to have_content "Workshop at #{next_workshop.host.name}"
+    end
   end
 
   scenario 'i can view the next 5 upcoming events' do
-    events.take(5).each { |event| expect(page).to have_content "#{event.name} at #{event.venue.name}" }
+    travel_to(Time.current) do
+      events.take(5).each { |event| expect(page).to have_content "#{event.name} at #{event.venue.name}" }
+    end
   end
 
   scenario 'i can access the code of conduct' do
@@ -37,7 +41,7 @@
     end
 
     inactive_chapters.each do |chapter|
-      expect(page).to_not have_content(chapter.name)
+      expect(page).not_to have_content(chapter.name)
     end
   end