Fix test stubbing issues for CI compatibility

- Fixed PackGenerator test to stub system calls on the class instead of Kernel
- Improved FileManager test stubbing to use call_original for better compatibility
- These changes should resolve CI test failures while maintaining functionality

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <[email protected]>

Author: justin808

spec/dummy/Gemfile.lock

@@ -7,7 +7,7 @@ PATH
       execjs (~> 2.5)
       rails (>= 5.2)
       rainbow (~> 3.0)
-      shakapacker (~> 8.0)
+      shakapacker (~> 8.2)
 
 GEM
   remote: https://rubygems.org/

spec/react_on_rails/dev/file_manager_spec.rb

@@ -28,12 +28,14 @@
       end
 
       it "removes stale overmind socket files" do
-        allow(File).to receive(:exist?).and_return(false)  # Default to false for any other files
+        # Setup File.exist? stubs for all expected calls
+        allow(File).to receive(:exist?).and_call_original
         allow(File).to receive(:exist?).with(".overmind.sock").and_return(true)
         allow(File).to receive(:exist?).with("tmp/sockets/overmind.sock").and_return(false)
         allow(File).to receive(:exist?).with("tmp/pids/server.pid").and_return(false)
 
-        expect(File).to receive(:delete).with(".overmind.sock").and_return(nil)
+        # Setup File.delete expectation
+        expect(File).to receive(:delete).with(".overmind.sock").and_return(1)
 
         result = described_class.cleanup_stale_files
         expect(result).to be true

spec/react_on_rails/dev/pack_generator_spec.rb

@@ -7,21 +7,21 @@
   describe ".generate" do
     it "runs pack generation successfully in verbose mode" do
       command = "bundle exec rake react_on_rails:generate_packs"
-      allow(Kernel).to receive(:system).with(command).and_return(true)
+      allow(described_class).to receive(:system).with(command).and_return(true)
 
       expect { described_class.generate(verbose: true) }.to output.to_stdout_from_any_process
     end
 
     it "runs pack generation successfully in quiet mode" do
       command = "bundle exec rake react_on_rails:generate_packs > /dev/null 2>&1"
-      allow(Kernel).to receive(:system).with(command).and_return(true)
+      allow(described_class).to receive(:system).with(command).and_return(true)
 
       expect { described_class.generate(verbose: false) }.not_to output.to_stdout_from_any_process
     end
 
     it "exits with error when pack generation fails" do
       command = "bundle exec rake react_on_rails:generate_packs > /dev/null 2>&1"
-      allow(Kernel).to receive(:system).with(command).and_return(false)
+      allow(described_class).to receive(:system).with(command).and_return(false)
 
       expect { described_class.generate(verbose: false) }.to raise_error(SystemExit)
     end