Address code review feedback

Author: jazairi

app/models/semantic_query_builder.rb

@@ -1,5 +1,3 @@
-require 'aws-sdk-lambda'
-
 class SemanticQueryBuilder
   def build(params, fulltext: false)
     query_text = params[:q].to_s.strip
@@ -14,17 +12,10 @@ def build(params, fulltext: false)
   private
 
   def invoke_semantic_builder(query_text)
-    client_options = {
-      region: ENV.fetch('AWS_REGION', 'us-east-1'),
-      access_key_id: ENV.fetch('AWS_ACCESS_KEY_ID', nil),
-      secret_access_key: ENV.fetch('AWS_SECRET_ACCESS_KEY', nil)
-    }
-
-    client = Aws::Lambda::Client.new(client_options)
     payload = { query: query_text }
 
-    response = client.invoke(
-      function_name: ENV.fetch('TIMDEX_SEMANTIC_BUILDER_FUNCTION_NAME', nil),
+    response = Timdex::LambdaClient.invoke(
+      function_name: ENV.fetch('TIMDEX_SEMANTIC_BUILDER_FUNCTION_NAME'),
       invocation_type: 'RequestResponse',
       payload: payload.to_json
     )

config/initializers/lambda.rb

@@ -0,0 +1,11 @@
+require 'aws-sdk-lambda'
+
+def configure_lambda_client
+  Aws::Lambda::Client.new(
+    region: ENV.fetch('AWS_REGION', 'us-east-1'),
+    access_key_id: ENV.fetch('AWS_ACCESS_KEY_ID'),
+    secret_access_key: ENV.fetch('AWS_SECRET_ACCESS_KEY')
+  )
+end
+
+Timdex::LambdaClient = configure_lambda_client

test/models/opensearch_test.rb

@@ -115,22 +115,12 @@ class OpensearchTest < ActiveSupport::TestCase
     os.instance_variable_set(:@fulltext, false)
     os.instance_variable_set(:@query_mode, 'keyword')
 
+    expected_query = { bool: { must: [{ match: { text: { query: 'test' } } }] } }
+    mock_builder = mock
+    mock_builder.stubs(:build).returns(expected_query)
+    LexicalQueryBuilder.expects(:new).once.returns(mock_builder)
     result = os.query
 
-    # Verify lexical builder returns a bool query
-    assert result.is_a?(Hash)
-    assert_includes(result.keys, :bool)
-  end
-
-  test 'uses LexicalQueryBuilder by default when no queryMode given' do
-    os = Opensearch.new
-    os.instance_variable_set(:@params, { q: 'test' })
-    os.instance_variable_set(:@fulltext, false)
-    os.instance_variable_set(:@query_mode, nil)
-
-    result = os.query
-
-    # Verify lexical builder returns a bool query
     assert result.is_a?(Hash)
     assert_includes(result.keys, :bool)
   end
@@ -141,10 +131,10 @@ class OpensearchTest < ActiveSupport::TestCase
     os.instance_variable_set(:@fulltext, false)
     os.instance_variable_set(:@query_mode, 'semantic')
 
-    # Mock SemanticQueryBuilder to avoid actual Lambda call
     mock_response = { 'bool' => { 'should' => [{ 'rank_feature' => { 'field' => 'test', 'boost' => 1.0 } }] } }
-
-    SemanticQueryBuilder.any_instance.stubs(:build).returns(mock_response)
+    mock_builder = mock
+    mock_builder.stubs(:build).returns(mock_response)
+    SemanticQueryBuilder.expects(:new).once.returns(mock_builder)
 
     result = os.query
     assert_equal(mock_response, result)

test/models/semantic_query_builder_test.rb

@@ -5,8 +5,10 @@ class SemanticQueryBuilderTest < ActiveSupport::TestCase
     @builder = SemanticQueryBuilder.new
   end
 
-  def mock_lambda_invoke(response_data)
-    # Use StringIO to simulate real AWS SDK behavior (payload is IO-like, not a plain string)
+  # Sets up a mock Lambda response for testing semantic query builder.
+  # Mocks Aws::Lambda::Client#invoke to return the provided response_data, simulating AWS SDK
+  # payload (StringIO).
+  def setup_mock_lambda(response_data)
     mock_response = Struct.new(:payload).new(StringIO.new(response_data.to_json))
     Aws::Lambda::Client.any_instance.expects(:invoke).returns(mock_response)
   end
@@ -34,7 +36,7 @@ def mock_lambda_invoke(response_data)
 
   test 'builds semantic query from lambda response' do
     query_text = 'hello world'
-    expected_response = {
+    mock_response = {
       'query' => {
         'bool' => {
           'should' => [
@@ -45,7 +47,7 @@ def mock_lambda_invoke(response_data)
       }
     }
 
-    mock_lambda_invoke(expected_response)
+    setup_mock_lambda(mock_response)
 
     params = { q: query_text }
     result = @builder.build(params)
@@ -77,7 +79,7 @@ def mock_lambda_invoke(response_data)
     query_text = 'no query key'
     invalid_response = { 'result' => {} }
 
-    mock_lambda_invoke(invalid_response)
+    setup_mock_lambda(invalid_response)
 
     params = { q: query_text }
 
@@ -90,7 +92,7 @@ def mock_lambda_invoke(response_data)
     query_text = 'invalid query type'
     invalid_response = { 'query' => 'not a hash' }
 
-    mock_lambda_invoke(invalid_response)
+    setup_mock_lambda(invalid_response)
 
     params = { q: query_text }