Optimize Fog mock setup: skip per-test reset for most specs

- Remove Fog::Mock.reset and bucket setup from spec_helper's before(:each)
- Initialize Fog mock buckets once in before(:suite) instead
- Create fog_spec_helper for specs that need clean Fog state between tests

This saves ~5ms per test by avoiding unnecessary Fog mock reset and
bucket recreation. Only ~24 specs that directly manipulate blobstores
need the per-test reset provided by fog_spec_helper.

Converted to fog_spec_helper (24 files):
- Blobstore job specs (upload, delete, cleanup)
- Blobstore lib specs (fog_client, retryable_client, etc.)
- Controller specs that handle buildpack/staging uploads
- Model specs for buildpack operations

Author: johha

spec/fog_spec_helper.rb

@@ -0,0 +1,21 @@
+# Use this helper for specs that need Fog/blobstore functionality with
+# a clean state between tests (upload, download, delete operations).
+#
+# This helper resets Fog mocks and recreates buckets before each test.
+#
+# For specs that don't need blobstore isolation, use spec_helper instead.
+
+require 'spec_helper'
+
+RSpec.configure do |config|
+  config.before 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
+  end
+end

spec/spec_helper.rb

@@ -159,6 +159,15 @@
       # calling this more than once will load tasks again and 'invoke' or 'execute' calls
       # will call rake tasks multiple times
       Application.load_tasks
+
+      # Initialize Fog mock buckets once at suite start.
+      # Tests that need isolated/clean Fog state should use fog_spec_helper.
+      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
@@ -169,15 +178,6 @@
       TestConfig.context = example.metadata[:job_context] || :api
       TestConfig.reset
 
-      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)

spec/unit/controllers/runtime/buildpack_bits_controller_spec.rb

@@ -1,4 +1,4 @@
-require 'spec_helper'
+require 'fog_spec_helper'
 
 ## NOTICE: Prefer request specs over controller specs as per ADR #0003 ##
 

spec/unit/controllers/runtime/buildpacks_controller_spec.rb

@@ -1,4 +1,4 @@
-require 'spec_helper'
+require 'fog_spec_helper'
 
 ## NOTICE: Prefer request specs over controller specs as per ADR #0003 ##
 

spec/unit/controllers/runtime/stagings_controller_spec.rb

@@ -1,4 +1,4 @@
-require 'spec_helper'
+require 'fog_spec_helper'
 
 ## NOTICE: Prefer request specs over controller specs as per ADR #0003 ##
 

spec/unit/jobs/runtime/blobstore_delete_spec.rb

@@ -1,4 +1,4 @@
-require 'spec_helper'
+require 'fog_spec_helper'
 
 module VCAP::CloudController
   module Jobs::Runtime

spec/unit/jobs/runtime/blobstore_upload_spec.rb

@@ -1,4 +1,4 @@
-require 'spec_helper'
+require 'fog_spec_helper'
 
 module VCAP::CloudController
   module Jobs::Runtime

spec/unit/jobs/runtime/buildpack_cache_cleanup_spec.rb

@@ -1,4 +1,4 @@
-require 'spec_helper'
+require 'fog_spec_helper'
 
 module VCAP::CloudController
   module Jobs::Runtime

spec/unit/jobs/v3/buildpack_cache_cleanup_spec.rb

@@ -1,4 +1,4 @@
-require 'spec_helper'
+require 'fog_spec_helper'
 
 module VCAP::CloudController
   module Jobs::V3

spec/unit/jobs/v3/buildpack_cache_delete_spec.rb

@@ -1,4 +1,4 @@
-require 'spec_helper'
+require 'fog_spec_helper'
 require 'jobs/v3/buildpack_cache_delete'
 
 module VCAP::CloudController