add tests for the api cache code

Gemfile

@@ -4,4 +4,5 @@ gemspec
 
 gem 'rake'
 gem 'pry'
-gem 'test-unit'
+gem 'test-unit'
+gem 'webmock', require: false

Gemfile.lock

@@ -20,8 +20,14 @@ GEM
       i18n (>= 1.6, < 2)
       minitest (>= 5.1)
       tzinfo (~> 2.0)
+    addressable (2.8.6)
+      public_suffix (>= 2.0.2, < 6.0)
+    bigdecimal (3.1.7)
     coderay (1.1.3)
     concurrent-ruby (1.1.10)
+    crack (1.0.0)
+      bigdecimal
+      rexml
     excon (0.95.0)
     faraday (2.0.1)
       faraday-net_http (~> 2.0)
@@ -32,6 +38,7 @@ GEM
     faraday-multipart (1.0.4)
       multipart-post (~> 2)
     faraday-net_http (2.1.0)
+    hashdiff (1.1.0)
     i18n (1.12.0)
       concurrent-ruby (~> 1.0)
     lz4-ruby (0.3.3)
@@ -44,13 +51,19 @@ GEM
     pry (0.14.1)
       coderay (~> 1.1)
       method_source (~> 1.0)
+    public_suffix (5.0.5)
     rake (13.0.6)
+    rexml (3.2.6)
     ruby2_keywords (0.0.5)
     spawnling (2.1.5)
     test-unit (3.5.7)
       power_assert
     tzinfo (2.0.5)
       concurrent-ruby (~> 1.0)
+    webmock (3.23.0)
+      addressable (>= 2.8.0)
+      crack (>= 0.3.2)
+      hashdiff (>= 0.4.0, < 2.0.0)
 
 PLATFORMS
   x86_64-darwin-21
@@ -62,6 +75,7 @@ DEPENDENCIES
   pry
   rake
   test-unit
+  webmock
 
 BUNDLED WITH
    2.4.21

config/config.test.rb

@@ -3,7 +3,8 @@
 # be set via ENV variable UT_APIKEY
 abort('UT_APIKEY env variable is not set. Canceling tests') unless ENV.include?('UT_APIKEY')
 abort('UT_APIKEY env variable is set to an empty value. Canceling tests') unless ENV['UT_APIKEY'].size > 5
-
+$API_CLIENT_INVALIDATE_CACHE = false
+$DEBUG_API_CLIENT = false
 LinkedData::Client.config do |config|
   config.rest_url   = 'https://data.bioontology.org'
   config.apikey     = ENV['UT_APIKEY']

test/middleware/test_cache.rb

@@ -0,0 +1,141 @@
+require_relative  '../test_case'
+require 'faraday'
+require 'active_support'
+require 'active_support/cache'
+require_relative '../../lib/ontologies_api_client/middleware/faraday-object-cache'
+require 'pry'
+require 'benchmark'
+require 'webmock'
+
+class FaradayObjectCacheTest < LinkedData::Client::TestCase
+  def setup
+    WebMock.disable!
+    apikey = LinkedData::Client.settings.apikey
+    @url = "#{LinkedData::Client.settings.rest_url}/ontologies/SNOMEDCT?apikey=#{apikey}"
+
+    @cache_store = ActiveSupport::Cache::MemoryStore.new
+    @app = Faraday.new(url: @url) do |faraday|
+      faraday.use Faraday::ObjectCache, store: @cache_store
+      faraday.adapter :excon
+    end
+  end
+
+  def test_cache_hit_for_get_request
+    body1, body2 = nil
+    # First request should not hit the cache
+    time1 = Benchmark.realtime do
+      response1 = @app.get
+      assert_equal 200, response1.status
+      assert uncached?(response1)
+
+      body1 = JSON.parse(response1.body)
+    end
+
+    time2 = Benchmark.realtime do
+      # Second request should hit the cache
+      response2 = @app.get
+      assert_equal 304, response2.status
+      assert cached?(response2)
+      body2 = response2.parsed_body.to_hash.stringify_keys
+    end
+
+    assert time2 < time1
+
+    body2.each do |k,v|
+      k = "@id" if k.eql?('id')
+      k = "@type" if k.eql?('type')
+
+      next if k.eql?('context') || k.eql?('links')
+
+      assert_equal v, body1[k]
+    end
+  end
+
+
+  def test_cache_invalidation
+    # Make a request and cache the response
+    response1 = @app.get
+    assert_equal 200, response1.status
+
+    response1 = @app.get
+    assert_equal 304, response1.status
+    assert cached?(response1)
+
+    # Invalidate the cache
+    response2 = @app.get do |req|
+      req.headers['invalidate_cache'] = true
+    end
+    assert_equal 200, response2.status
+    assert uncached?(response2)
+  end
+
+  def test_cache_expiration
+    WebMock.enable!
+    WebMock.stub_request(:get, @url)
+           .to_return(headers: { 'Cache-Control': "max-age=1" , 'Last-Modified': Time.now.httpdate}, body: {result: 'hello'}.to_json)
+
+
+    # Make a request and cache the response with a short expiry time
+    response1 = @app.get
+    assert_equal 200, response1.status
+
+    # Wait for the cache to expire
+    sleep 2
+
+    response2 = @app.get
+
+    assert_equal 200, response2.status
+    assert uncached?(response2)
+
+    sleep 2
+
+    WebMock.stub_request(:get, @url)
+           .to_return(headers: { 'Cache-Control': "max-age=100" , 'Last-Modified': Time.now.httpdate}, body: {result: 'hello'}.to_json)
+    @app.get
+
+
+    # Wait for the cache to expire
+    sleep 2
+
+    response2 = @app.get
+
+    assert cached?(response2)
+
+    WebMock.disable!
+  end
+
+  def test_cache_last_modified
+    WebMock.enable!
+    # Make a request with Last-Modified header
+    WebMock.stub_request(:get, @url)
+           .to_return(headers: { 'Cache-Control': "max-age=1", 'Last-Modified': 3.days.ago.to_time.httpdate}, body: {result: 'hello'}.to_json, status: 304)
+
+    @app.get
+
+    response2 = @app.get
+    assert cached?(response2)
+
+    sleep 1
+
+    WebMock.stub_request(:get, @url)
+           .to_return(headers: { 'Cache-Control': "max-age=10", 'Last-Modified': 1.days.ago.to_time.httpdate}, body: {result: 'hello'}.to_json, status: 304)
+
+    response2 = @app.get
+    assert refreshed?(response2)
+    WebMock.disable!
+  end
+
+
+  private
+  def cached?(response)
+    response.env.response_headers['x-rack-cache'].eql?('hit')
+  end
+
+  def uncached?(response)
+    response.env.response_headers['x-rack-cache'].eql?('miss')
+  end
+
+  def refreshed?(response)
+    response.env.response_headers['x-rack-cache'].eql?('fresh')
+  end
+end