Split UnitTestGenerator into generator and validator.

Issue #170 aims to tackle the refactor of UnitTestGenerator and
this is an attempt to split UnitTestGenerator into generator and
validator. This PR is a first of a series of refactoring we can
apply to UnitTestGenerator.

* Created a new class `UnitTestValidator` by copying running,
  validating and processing coverage from `UnitTestGenerator`

* Doesn't include any cleanup or optimization and kept the PR
  to be minimal structural changes.

* Use prompt from UnitTestGenerator when storing a failed test
  into the database.

cover_agent/CoverAgent.py

@@ -7,6 +7,7 @@
 from cover_agent.CustomLogger import CustomLogger
 from cover_agent.ReportGenerator import ReportGenerator
 from cover_agent.UnitTestGenerator import UnitTestGenerator
+from cover_agent.UnitTestValidator import UnitTestValidator
 from cover_agent.UnitTestDB import UnitTestDB
 
 class CoverAgent:
@@ -27,6 +28,21 @@ def __init__(self, args):
         self._duplicate_test_file()
 
         self.test_gen = UnitTestGenerator(
+            source_file_path=args.source_file_path,
+            test_file_path=args.test_file_output_path,
+            project_root=args.project_root,
+            code_coverage_report_path=args.code_coverage_report_path,
+            test_command=args.test_command,
+            test_command_dir=args.test_command_dir,
+            included_files=args.included_files,
+            coverage_type=args.coverage_type,
+            additional_instructions=args.additional_instructions,
+            llm_model=args.model,
+            api_base=args.api_base,
+            use_report_coverage_feature_flag=args.use_report_coverage_feature_flag,
+        )
+
+        self.test_validator = UnitTestValidator(
             source_file_path=args.source_file_path,
             test_file_path=args.test_file_output_path,
             project_root=args.project_root,
@@ -123,29 +139,31 @@ def run(self):
         test_results_list = []
 
         # Run initial test suite analysis
-        self.test_gen.get_coverage_and_build_prompt()
-        self.test_gen.initial_test_suite_analysis()
+        self.test_validator.initial_test_suite_analysis()
+        failed_test_runs = self.test_validator.get_coverage()
+        self.test_gen.build_prompt(failed_test_runs)
 
         # Loop until desired coverage is reached or maximum iterations are met
         while (
-            self.test_gen.current_coverage < (self.test_gen.desired_coverage / 100)
+            self.test_validator.current_coverage < (self.test_validator.desired_coverage / 100)
             and iteration_count < self.args.max_iterations
         ):
             # Log the current coverage
             self.logger.info(
-                f"Current Coverage: {round(self.test_gen.current_coverage * 100, 2)}%"
+                f"Current Coverage: {round(self.test_validator.current_coverage * 100, 2)}%"
             )
-            self.logger.info(f"Desired Coverage: {self.test_gen.desired_coverage}%")
+            self.logger.info(f"Desired Coverage: {self.test_validator.desired_coverage}%")
 
             # Generate new tests
-            generated_tests_dict = self.test_gen.generate_tests()
+            generated_tests_dict = self.test_gen.generate_tests(failed_test_runs)
 
             # Loop through each new test and validate it
             for generated_test in generated_tests_dict.get("new_tests", []):
                 # Validate the test and record the result
-                test_result = self.test_gen.validate_test(
+                test_result = self.test_validator.validate_test(
                     generated_test, self.args.run_tests_multiple_times
                 )
+                test_result["prompt"] = self.test_gen.prompt["user"] # get the prompt used to generate the test so that it is stored in the database
                 test_results_list.append(test_result)
 
                 # Insert the test result into the database
@@ -155,17 +173,17 @@ def run(self):
             iteration_count += 1
 
             # Check if the desired coverage has been reached
-            if self.test_gen.current_coverage < (self.test_gen.desired_coverage / 100):
+            if self.test_validator.current_coverage < (self.test_validator.desired_coverage / 100):
                 # Run the coverage tool again if the desired coverage hasn't been reached
-                self.test_gen.run_coverage()
+                self.test_validator.run_coverage()
 
         # Log the final coverage
-        if self.test_gen.current_coverage >= (self.test_gen.desired_coverage / 100):
+        if self.test_validator.current_coverage >= (self.test_validator.desired_coverage / 100):
             self.logger.info(
-                f"Reached above target coverage of {self.test_gen.desired_coverage}% (Current Coverage: {round(self.test_gen.current_coverage * 100, 2)}%) in {iteration_count} iterations."
+                f"Reached above target coverage of {self.test_validator.desired_coverage}% (Current Coverage: {round(self.test_validator.current_coverage * 100, 2)}%) in {iteration_count} iterations."
             )
         elif iteration_count == self.args.max_iterations:
-            failure_message = f"Reached maximum iteration limit without achieving desired coverage. Current Coverage: {round(self.test_gen.current_coverage * 100, 2)}%"
+            failure_message = f"Reached maximum iteration limit without achieving desired coverage. Current Coverage: {round(self.test_validator.current_coverage * 100, 2)}%"
             if self.args.strict_coverage:
                 # User requested strict coverage (similar to "--cov-fail-under in pytest-cov"). Fail with exist code 2.
                 self.logger.error(failure_message)
@@ -175,10 +193,10 @@ def run(self):
 
         # Provide metrics on total token usage
         self.logger.info(
-            f"Total number of input tokens used for LLM model {self.test_gen.ai_caller.model}: {self.test_gen.total_input_token_count}"
+            f"Total number of input tokens used for LLM model {self.test_gen.ai_caller.model}: {self.test_gen.total_input_token_count + self.test_validator.total_input_token_count}"
         )
         self.logger.info(
-            f"Total number of output tokens used for LLM model {self.test_gen.ai_caller.model}: {self.test_gen.total_output_token_count}"
+            f"Total number of output tokens used for LLM model {self.test_gen.ai_caller.model}: {self.test_gen.total_output_token_count + self.test_validator.total_output_token_count}"
         )
 
         # Generate a report