Optimize spec_helper: skip Fog reset for most tests

Move Fog mock bucket setup to before(:suite) and only reset Fog mocks
for tests that explicitly need it (tagged with :fog_reset).

This optimization saves ~5.3ms per test by avoiding unnecessary bucket
recreation. Only ~6% of tests actually use blobstores, so this benefits
the majority of tests.

Tests that need a clean Fog state can add `:fog_reset` metadata to opt-in
to the previous behavior.

Author: johha

spec/spec_helper.rb

@@ -159,6 +159,14 @@
       # calling this more than once will load tasks again and 'invoke' or 'execute' calls
       # will call rake tasks multiple times
       Application.load_tasks
+
+      # Set up Fog mock buckets once at suite start instead of every test
+      if Fog.mock?
+        CloudController::DependencyLocator.instance.droplet_blobstore.ensure_bucket_exists
+        CloudController::DependencyLocator.instance.package_blobstore.ensure_bucket_exists
+        CloudController::DependencyLocator.instance.global_app_bits_cache.ensure_bucket_exists
+        CloudController::DependencyLocator.instance.buildpack_blobstore.ensure_bucket_exists
+      end
     end
 
     rspec_config.before do
@@ -169,21 +177,24 @@
       TestConfig.context = example.metadata[:job_context] || :api
       TestConfig.reset
 
-      Fog::Mock.reset
+      VCAP::CloudController::SecurityContext.clear
+      VCAP::Request.current_id = nil
+      allow_any_instance_of(VCAP::CloudController::UaaTokenDecoder).to receive(:uaa_issuer).and_return(UAAIssuer::ISSUER)
 
+      mock_redis = MockRedis.new
+      allow(Redis).to receive(:new).and_return(mock_redis)
+    end
+
+    # Only reset Fog mocks for tests that use blobstores (tagged with :fog_reset)
+    # This avoids the overhead of clearing and recreating buckets for every test
+    rspec_config.before(:each, :fog_reset) do
+      Fog::Mock.reset
       if Fog.mock?
         CloudController::DependencyLocator.instance.droplet_blobstore.ensure_bucket_exists
         CloudController::DependencyLocator.instance.package_blobstore.ensure_bucket_exists
         CloudController::DependencyLocator.instance.global_app_bits_cache.ensure_bucket_exists
         CloudController::DependencyLocator.instance.buildpack_blobstore.ensure_bucket_exists
       end
-
-      VCAP::CloudController::SecurityContext.clear
-      VCAP::Request.current_id = nil
-      allow_any_instance_of(VCAP::CloudController::UaaTokenDecoder).to receive(:uaa_issuer).and_return(UAAIssuer::ISSUER)
-
-      mock_redis = MockRedis.new
-      allow(Redis).to receive(:new).and_return(mock_redis)
     end
 
     rspec_config.around do |example|