Add specs for committed cache store to prevent file creep

spec/committed_cache_spec.rb

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+# frozen_string_literal: true
+
+require "spec_helper"
+require "json"
+
+RSpec.describe "Committed Cache Directory" do
+  # Use a non-git-ignored directory for cache storage
+  let(:committed_cache_path) { File.join(__dir__, "fixtures", "committed_cache") }
+  # Configure store with raw mode to avoid compression
+  let(:store) { ActiveSupport::Cache::SourceControlCacheStore.new(cache_path: committed_cache_path, compress: false) }
+
+  # Predefined cache entries (keys and values as JSON strings for readability)
+  let(:cache_entries) do
+    {
+      "user:123:profile" => { name: "John Doe", email: "john@example.com" }.to_json,
+      "user:456:profile" => { name: "Jane Smith", email: "jane@example.com" }.to_json,
+      "config:app:settings" => { theme: "dark", language: "en" }.to_json
+    }
+  end
+
+  # File list helpers
+  let(:key_files) { Dir.glob(File.join(committed_cache_path, "*.key")) }
+  let(:value_files) { Dir.glob(File.join(committed_cache_path, "*.value")) }
+  let(:all_files) do
+    Dir.glob(File.join(committed_cache_path, "**", "*"), File::FNM_DOTMATCH)
+      .reject { |f| File.directory?(f) }
+      .sort
+  end
+  let(:key_contents) { key_files.map { |f| File.read(f) }.sort }
+
+  # Shared examples for validating cache state
+  shared_examples "validates committed cache files" do
+    it "has the expected number of key files" do
+      expect(key_files.length).to eq(3)
+    end
+
+    it "has the expected number of value files" do
+      expect(value_files.length).to eq(3)
+    end
+
+    it "preserves original keys in .key files" do
+      expect(key_contents).to contain_exactly(*cache_entries.keys.sort)
+    end
+
+    it "has valid value files that can be deserialized" do
+      # All value files should be readable
+      value_files.each do |value_file|
+        expect(File.read(value_file).length).to be > 0
+      end
+    end
+
+    it "maintains the exact file count" do
+      # Should have exactly 7 files (3 entries × 2 files each + 1 README.md)
+      expect(all_files.length).to eq(7)
+    end
+  end
+
+  describe "cache stability verification" do
+    # Capture initial state for comparison
+    let(:initial_file_list) { all_files }
+
+    before(:each) do
+      # Ensure cache entries exist before each test using raw mode
+      cache_entries.each do |key, value|
+        store.write(key, value, raw: true)
+      end
+    end
+
+    it "does not create new files when reading existing entries" do
+      # Capture state before reading
+      files_before = initial_file_list
+
+      # Read existing entries with raw mode
+      cache_entries.keys.each do |key|
+        store.read(key, raw: true)
+      end
+
+      # Verify no new files were created
+      expect(all_files).to eq(files_before)
+    end
+
+    it "does not create new files when writing to existing keys with same values" do
+      # Capture state before writing
+      files_before = initial_file_list
+
+      # Write same values to existing keys with raw mode
+      cache_entries.each do |key, value|
+        store.write(key, value, raw: true)
+      end
+
+      # Verify no new files were created (same files should exist)
+      expect(all_files).to eq(files_before)
+    end
+
+    it "has all expected cache files present" do
+      # Verify that all expected keys exist
+      cache_entries.each do |key, expected_value|
+        expect(store.read(key, raw: true)).to eq(expected_value)
+      end
+    end
+
+    it "does not create new files during multiple read operations" do
+      # Capture state before reading
+      files_before = initial_file_list
+
+      # Perform multiple read operations
+      10.times do
+        cache_entries.keys.each do |key|
+          store.read(key, raw: true)
+        end
+      end
+
+      # Verify no new files were created
+      expect(all_files).to eq(files_before)
+    end
+
+    include_examples "validates committed cache files"
+  end
+
+  describe "file content verification" do
+    include_examples "validates committed cache files"
+
+    it "includes README.md documentation" do
+      readme_path = File.join(committed_cache_path, "README.md")
+      expect(File.exist?(readme_path)).to be true
+      expect(File.read(readme_path)).to include("Committed Cache Directory")
+    end
+  end
+end

spec/fixtures/committed_cache/39cc398b810ada504bc9d10624575cf9.key

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+config:app:settings

spec/fixtures/committed_cache/39d971627e43c9bf240a49201b62f115.key

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+user:123:profile

spec/fixtures/committed_cache/README.md

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+# Committed Cache Directory
+
+This directory contains cache files that are intentionally committed to source control for testing purposes.
+
+## Purpose
+
+This directory is used by the `committed_cache_spec.rb` test suite to verify that:
+1. Cache files can be stored in a non-git-ignored directory
+2. Once populated, no new files are created on subsequent runs
+3. The cache remains stable across different environments and PRs
+
+## Files
+
+The cache files in this directory are generated by the test suite and should not be manually modified.
+They represent a stable set of cache entries used for validation testing.
+
+## Do Not Ignore
+
+**Important:** This directory and its contents should NOT be added to `.gitignore`. 
+The cache files are intentionally version-controlled to ensure test stability.

spec/fixtures/committed_cache/ca63624a99ad3e461af0d7c8a2d5a520.key

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+user:456:profile