anchor.diff:  import 'package:injector/injector.dart';
   import 'package:ml_algo/src/classifier/linear/logistic_regressor/logistic_regressor.dart';
  +import 'package:ml_algo/src/cost_function/cost_function.dart';
   import 'package:ml_algo/src/cost_function/cost_function_factory.dart';
  +import 'package:ml_algo/src/cost_function/cost_function_type.dart';
   import 'package:ml_algo/src/di/injector.dart';
  +import 'package:ml_algo/src/linear_optimizer/linear_optimizer.dart';
  +import 'package:ml_algo/src/link_function/link_function.dart';
   import 'package:ml_algo/src/link_function/link_function_factory.dart';
   import 'package:ml_algo/src/linear_optimizer/gradient/learning_rate_generator/learning_rate_type.dart';
   import 'package:ml_algo/src/linear_optimizer/initial_weights_generator/initial_weights_type.dart';
   import 'package:ml_algo/src/linear_optimizer/linear_optimizer_factory.dart';
   import 'package:ml_algo/src/linear_optimizer/linear_optimizer_type.dart';
  +import 'package:ml_algo/src/link_function/link_function_type.dart';
   import 'package:ml_dataframe/ml_dataframe.dart';
   import 'package:ml_linalg/dtype.dart';
   import 'package:ml_linalg/matrix.dart';
  +import 'package:ml_tech/unit_testing/matchers/iterable_2d_almost_equal_to.dart';
   import 'package:mockito/mockito.dart';
   import 'package:test/test.dart';
   
  
positive.code:         initialWeights: initialWeights,
          randomSeed: 123,
        );
  
        verify(optimizerMock.findExtrema(
            initialWeights: argThat(
                equals(initialWeights),
                named: 'initialWeights'
            ),
            isMinimizingObjective: false
        )).called(1);
      });
    });
  
negative.code: 
  void main() {
    group('LogisticRegressor', () {
      final observations = DataFrame([
        <num>[10.1, 10.2, 12.0, 13.4, 1],
        <num>[ 3.1,  5.2,  6.0, 77.4, 0],
      ], headerExists: false);
  
      final initialWeights = Matrix.fromList([
        [10],
        [20],
        [30],
        [40],
      ]);
  
      LinkFunction linkFunctionMock;
      LinkFunctionFactory linkFunctionFactoryMock;
  
      CostFunction costFunctionMock;
      CostFunctionFactory costFunctionFactoryMock;
  
      LinearOptimizer optimizerMock;
      LinearOptimizerFactory optimizerFactoryMock;
  
      setUp(() {
        linkFunctionMock = LinkFunctionMock();
        linkFunctionFactoryMock = createLinkFunctionFactoryMock(linkFunctionMock);
  
        costFunctionMock = CostFunctionMock();
        costFunctionFactoryMock = createCostFunctionFactoryMock(costFunctionMock);
  
        optimizerMock = LinearOptimizerMock();
        optimizerFactoryMock = createOptimizerFactoryMock(optimizerMock);
  
        injector = Injector()
          ..registerSingleton<LinkFunctionFactory>(
                  (_) => linkFunctionFactoryMock)
          ..registerDependency<CostFunctionFactory>(
                  (_) => costFunctionFactoryMock)
          ..registerSingleton<LinearOptimizerFactory>(
                  (_) => optimizerFactoryMock);
  
        LogisticRegressor(
          observations,
  