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Unit testing with XUnit, ADO.NET, SQL Server

This question is about using XUnit with ADO.NET for a To Do List app using Nancy. I'm hoping for some insight on why an Assert.Equal test is failing, even though the outputs appear to be identical.
I have a Task class with two properties: id and description.
The database for this app has a corresponding tasks table. User input is used for the description, and the id is an auto-incrementing identity column.
The Task class has a static List property All(). Each task is added to All(), and you can retrieve the list of all tasks by calling Task.All().
Here's the Task class:
namespace ToDoList
{
public class Task
{
private int id;
private string description;
public Task(string Description, int Id = 0)
{
id = Id;
description = Description;
}
public int GetId()
{
return id;
}
public string GetDescription()
{
return description;
}
public void SetDescription(string newDescription)
{
description = newDescription;
}
public static List<Task> All()
{
List<Task> AllTasks = new List<Task>{};
SqlConnection conn = DB.Connection();
SqlDataReader rdr = null;
conn.Open();
SqlCommand cmd = new SqlCommand("SELECT * FROM tasks", conn);
rdr = cmd.ExecuteReader();
while(rdr.Read())
{
int taskId = rdr.GetInt32(0);
string taskDescription = rdr.GetString(1);
Task newTask = new Task(taskDescription, taskId);
AllTasks.Add(newTask);
}
conn.Close();
return AllTasks;
}
public void Save()
{
SqlConnection conn = DB.Connection();
SqlDataReader rdr;
conn.Open();
SqlCommand cmd = new SqlCommand("INSERT INTO tasks (description) OUTPUT INSERTED.id VALUES (#TaskDescription)", conn);
SqlParameter testParameter = new SqlParameter();
testParameter.ParameterName = "#TaskDescription";
testParameter.Value = this.GetDescription();
cmd.Parameters.Add(testParameter);
rdr = cmd.ExecuteReader();
while(rdr.Read())
{
this.id = rdr.GetInt32(0);
}
conn.Close();
}
public static void DeleteAll()
{
SqlConnection conn = DB.Connection();
conn.Open();
SqlCommand cmd = new SqlCommand("DELETE FROM tasks;", conn);
cmd.ExecuteNonQuery();
}
}
I define DB.Connection as the connection string in Startup.cs:
...
public class DB
{
public static SqlConnection Connection()
{
SqlConnection conn = new SqlConnection("Data Source=(localdb)\\mssqllocaldb;Initial Catalog=todo_test;Integrated Security=SSPI;");
return conn;
}
}
...
Now here's the test I use to see if it works:
namespace ToDoList
{
public class ToDoTest : IDisposable
{
[Fact]
public void Test_All()
{
//Arrange
var description = "Wash the dog";
var description2 = "Water the plants";
Task testTask = new Task(description);
testTask.Save();
Task testTask2 = new Task(description2);
testTask2.Save();
//Act
List<Task> result = Task.All();
List<Task> testList = new List<Task>{testTask, testTask2};
//Assert
Assert.Equal(result, testList);
}
public void Dispose()
{
Task.DeleteAll();
}
}
}
The output in the console only says that the test failed:
ToDoList.ToDoTest.Test_All [FAIL]
Assert.Equal() Failure
Expected: List<Task> [Task { }, Task { }]
Actual: List<Task> [Task { }, Task { }]
I did some console logs, and the ids and descriptions for the tasks in each list are identical.
In addition, when I test with:
List<Task> result = new List<Task>{testTask, testTask2};
List<Task> testList = new List<Task>{testTask, testTask2};
The test passes.
I'm not really sure how to approach this to see why the test is failing. Any ideas would be great!

You need to overwrite the Task.Equals() method for that Assert.Equal() to succeed, otherwise the default reference equals semantics will be applied.

How to load data from MySql database into list(Console-Based app)?

I have created a database with 1 table "emp" and have some data in it. Now every time i start the app, i want a list to fetch the data from db and save it in list because i want to perform some calculations like tax and Gross-Salary on data at runtime for display only(don't want to save it in db ). I have tried many times but i am unable to understand how this can be done. This is my code:
Main Class:
static void Main(string[] args)
{
empDB empDB1 = new empDB();
List<emplyee> empLST1 = new List<emplyee>();
if (empLST1 == null)
{
empDB1.loadLST(out empLST1);
}
}
empDB Class:
class empDB
{
private string ConnectionString = #"server=localhost;DATABASE=hris;uid=root;Password=123456;";
internal void loadLST(out List<emplyee> loadedLST)
{
string query = "select name, grade from emp";
try
{
MySqlConnection con = new MySqlConnection(ConnectionString);
con.Open();
MySqlDataReader rdr = null;
MySqlCommand cmd = new MySqlCommand(query, con);
rdr = cmd.ExecuteReader();
while(rdr.Read())
{
List<employee> returnedLst = new List<employee>();
returnedLst.Add(rdr["name"].ToString(), rdr["grade"].ToString());
}
loadedLst = returnedLst;
}
catch(Exception ex)
{
Console.WriteLine(ex.Message);
}
}
}
I have no idea even if my approach is right or not. I have googled it a few times but i just started working in .net a few days ago so i don't understand how to do it.
Okay i tried this and it also dosn't work:
internal void GetDatabaseList()
{
List<employee> databases = new List<employee>();
MySqlConnection con = new MySqlConnection(ConnectionString);
{
con.Open();
DataTable tbl = con.GetSchema("Databases");
con.Close();
foreach (DataRow row in tbl.Rows)
{
databases.Add(row["hris"].ToString());
}
}
}

static void Main(string[] args)
{
empDB empDB1 = new empDB();
List<emplyee> empLST1 = new List<emplyee>();
**if (empLST1 == null)
{
empDB1.loadLST(out empLST1);
}**
}
this will always be false because you defined empLST1 as a new List, meaning its not null
try this
public class Employee
{
public string Name { get; set; }
public string Grade { get; set; }
}
static void Main(string[] args)
{
empDB empDB1 = new empDB();
List<Employee> empLST1 = new List<Employee>();
empDB1.loadLST(ref empLST1);
}
public class empDB
{
public void loadLst(ref List<Employee> loadedLST)
{
string query = "select name, grade from emp";
try
{
MySqlConnection con = new MySqlConnection(ConnectionString);
con.Open();
MySqlDataReader rdr = null;
MySqlCommand cmd = new MySqlCommand(query, con);
rdr = cmd.ExecuteReader();
while (rdr.Read())
{
Employee emp = new Employee();
emp.Name = rdr["name"].ToString();
emp.Grade = rdr["grade"].ToString();
loadedLST.Add(emp);
}
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
}
}
}

Assuming, that that employee class looks like this:
class employee
{
public string Name { get; set; }
public string Grade { get; set; }
}
I'd rewrite loadLST like this:
internal List<employee> loadLST()
{
string query = "select name, grade from emp";
// we should dispose IDisposable implementations:
// connection, command and data reader
using (var con = new MySqlConnection(ConnectionString))
{
con.Open();
using (var cmd = new MySqlCommand(query, con))
using (var rdr = cmd.ExecuteReader())
{
// it is hard to maintain manual mapping
// between query results and objects;
// let's use helper like Automapper to make this easier
Mapper.CreateMap<IDataReader, employee>();
Mapper.AssertConfigurationIsValid();
return Mapper.Map<List<employee>>(rdr);
}
}
}
Improvements:
IDisposable implementations must be disposed explicitly (see this and this)
to avoid manual mapping code, which maps the result from data reader and object (employee instance in your case), the code uses Automapper package
exception handling and out parameter are thrown away. There's no need for exception handling and out parameter here, unless you're writing method like TryToDoSomething (and even in that case your method must return bool to indicate the state of operation, and catch only specific exceptions instead of Exception).
Also note, that your code doesn't match naming guidelines (e.g., employee should be Employee).

Use of Generic Delegates

We know that "Action, Func and Predicate are pre-defined Generic delegates. So as delegate they can point to functions with specified signature."
I have following data-access scenario in which Func<T,R> helps in avoiding a foreach loop in the calling method. The approach 2 doesn’t have looping. Here Func<T,R> helped to avoid loop.
What are the other scenarios for generic delegates in which it can save lots of lines of code?
REFERENCES
Dynamically Composing Expression Predicates
Advanced C#
C#/.NET Little Wonders: The Predicate, Comparison, and Converter Generic Delegates
Func vs. Action vs. Predicate
What is Func, how and when is it used
How can I pass in a func with a generic type parameter?
CODE
Approach 1
public class MyCommonDAL
{
public static IEnumerable<IDataRecord> ExecuteQueryWithTextCommandType(string commandText, List<SqlParameter> commandParameters)
{
using (SqlConnection connection = new SqlConnection(connectionString))
{
using (SqlCommand command = new SqlCommand())
{
command.Connection = connection;
command.CommandType = CommandType.Text;
command.CommandText = commandText;
command.CommandTimeout = 0;
command.Parameters.AddRange(commandParameters.ToArray());
connection.Open();
using (var rdr = command.ExecuteReader())
{
while (rdr.Read())
{
yield return rdr;
}
rdr.Close();
}
}
}
}
}
public class MyLogDAL
{
public List<LogSeverityType> GetLogSeveritiesFirstApproach(LogSeverityType logSeverityType)
{
List<SqlParameter> commandParameters = new List<SqlParameter>()
{
new SqlParameter {ParameterName = "#CreatedDateTime",
Value = logSeverityType.CreatedDateTime,
SqlDbType = SqlDbType.DateTime}
};
string commandText = #"SELECT * FROM dbo.LogSeverityType WHERE CreatedDateTime > #CreatedDateTime";
var results = MyCommonDAL.ExecuteQueryWithTextCommandType(commandText, commandParameters);
List<LogSeverityType> logSeverities = new List<LogSeverityType>();
//LOOP
foreach (IDataRecord rec in results)
{
LogSeverityType objLogSeverityType = LogSeverityType.LogSeverityTypeFactory(rec);
logSeverities.Add(objLogSeverityType);
}
return logSeverities;
}
}
Approach 2
public class MyCommonDAL
{
public static IEnumerable<T> ExecuteQueryGenericApproach<T>(string commandText, List<SqlParameter> commandParameters, Func<IDataRecord, T> factoryMethod)
{
//Action, Func and Predicate are pre-defined Generic delegates.
//So as delegate they can point to functions with specified signature.
using (SqlConnection connection = new SqlConnection(connectionString))
{
using (SqlCommand command = new SqlCommand())
{
command.Connection = connection;
command.CommandType = CommandType.Text;
command.CommandText = commandText;
command.CommandTimeout = 0;
command.Parameters.AddRange(commandParameters.ToArray());
connection.Open();
using (var rdr = command.ExecuteReader())
{
while (rdr.Read())
{
yield return factoryMethod(rdr);
}
rdr.Close();
}
}
}
}
}
public class MyLogDAL
{
public List<LogSeverityType> GetLogSeveritiesSecondApproach(LogSeverityType logSeverityType)
{
List<SqlParameter> commandParameters = new List<SqlParameter>()
{
new SqlParameter {ParameterName = "#CreatedDateTime",
Value = logSeverityType.CreatedDateTime,
SqlDbType = SqlDbType.DateTime}
};
string commandText = #"SELECT * FROM dbo.LogSeverityType WHERE CreatedDateTime > #CreatedDateTime";
//var results = MyCommonDAL.ExecuteQueryWithTextCommandType(commandText, commandParameters);
IEnumerable<LogSeverityType> logSeverities = MyCommonDAL.ExecuteQueryGenericApproach<LogSeverityType>(commandText, commandParameters, LogSeverityType.LogSeverityTypeFactory);
//foreach (IDataRecord rec in results)
//{
// LogSeverityType objLogSeverityType = LogSeverityType.LogSeverityTypeFactory(rec);
// logSeverities.Add(objLogSeverityType);
//}
return logSeverities.ToList();
}
}
Other Code Required
public class LogSeverityType
{
public int LogSeverityTypeID { get; set; }
public string Name { get; set; }
public string Description { get; set; }
public DateTime CreatedDateTime { get; set; }
public static LogSeverityType LogSeverityTypeFactory(IDataRecord record)
{
return new LogSeverityType
{
LogSeverityTypeID = (int)record[0],
Name = (string) record[1],
Description = (string)record[2],
CreatedDateTime = (DateTime) record[3]
};
}
}
static void Main(string[] args)
{
MyLogDAL logDAL = new MyLogDAL();
LogSeverityType logSeverityType = new LogSeverityType();
logSeverityType.CreatedDateTime = Convert.ToDateTime("1/1/2000");
List<LogSeverityType> logSeverities = logDAL.GetLogSeveritiesSecondApproach(logSeverityType);
}

I use generic delegates when parsing / finding nodes in XML / HTML documents, and assigning the values to properties. I wrote a blog post about it, which shows refactoring the code to pass in a generic delegate, and how much code was removed.

Types that own disposable fields should be disposable. how to solve this warning?

I tried using Run Code Analysis option in VisualStudio 2012, as a result of it I got a warning as
CA1001 Types that own disposable fields should be disposable
Implement IDisposable on 'DBConnectivity'
because it creates members of the following IDisposable types: 'SqlConnection', 'SqlCommand'.
I referred some question in SO, but I couldn't catch the point regarding IDisposable
and following is the class, responsible for this warning.
class DBConnectivity
{
public SqlConnection connection = null;
public SqlCommand command = null;
public SqlDataReader dataReader = null;
public string connectionString = null;
public List<MasterTableAttributes> masterTableList;
public DBConnectivity()
{
connectionString = ConfigurationManager.ConnectionStrings["Master"].ConnectionString;
connection = new SqlConnection(connectionString.ToString());
//-----Master table results
connection.Open();
string masterSelectQuery = "SELECT * FROM MASTER_TABLE";
command = new SqlCommand(masterSelectQuery, connection);
dataReader = command.ExecuteReader();
masterTableList = new List<MasterTableAttributes>();
while (dataReader.Read())
{
MasterTableAttributes masterTableAttribute = new MasterTableAttributes()
{
fileId = Convert.ToInt32(dataReader["Id"]),
fileName = Convert.ToString(dataReader["FileName"]),
frequency = Convert.ToString(dataReader["Frequency"]),
scheduledTime = Convert.ToString(dataReader["Scheduled_Time"])
};
masterTableList.Add(masterTableAttribute);
}
dataReader.Close();
connection.Close();
}
}
I am really confused in implementing the IDisposable. Any help appreciated?

I fully agree with the compiler - you need to dispose your fields here, or (as already noted) - not make them fields in the first place:
class DBConnectivity : IDisposable // caveat! read below first
{
public void Dispose() {
if(connection != null) { connection.Dispose(); connection = null; }
if(command != null) { command.Dispose(); command = null; }
if(dataReader != null) { dataReader.Dispose(); dataReader = null; }
}
Note that you would then use this type via using(...)
However! It looks like a static method would be more appropriate:
static class DBConnectivity
{
public static List<MasterTableAttributes> GetMasterTableList()
{
var connectionString = ConfigurationManager.ConnectionStrings["Master"].ConnectionString;
using(var connection = new SqlConnection(connectionString))
{
connection.Open();
const string masterSelectQuery = "SELECT * FROM MASTER_TABLE";
using(var command = new SqlCommand(masterSelectQuery, connection))
using(var dataReader = command.ExecuteReader())
{
var masterTableList = new List<MasterTableAttributes>();
while (dataReader.Read())
{
MasterTableAttributes masterTableAttribute = new MasterTableAttributes()
{
fileId = Convert.ToInt32(dataReader["Id"]),
fileName = Convert.ToString(dataReader["FileName"]),
frequency = Convert.ToString(dataReader["Frequency"]),
scheduledTime = Convert.ToString(dataReader["Scheduled_Time"])
};
masterTableList.Add(masterTableAttribute);
}
return masterTableList;
}
}
}
}
or perhaps simpler with a tool like "dapper":
static class DBConnectivity
{
public static List<MasterTableAttributes> GetMasterTableList()
{
var connectionString = ConfigurationManager.ConnectionStrings["Master"].ConnectionString;
using(var connection = new SqlConnection(connectionString))
{
connection.Open();
const string sql = "SELECT Id as [FileId], FileName, Frequency, Scheduled_Time as [ScheduledTime] FROM MASTER_TABLE";
return connection.Query<MasterTableAttributes>(sql).ToList();
}
}
}

If that is you complete class you should move all the SQL variables inside the constructor. Or perhaps change the constructor to a static function that return the masterTableList

Why do I get Error StreamReader in my .NET webservice with JSON?

I want to create a .NET webservice using C# with JSON. but I've error in my return statement on my webservice, cannot implicitly convert type 'string' to 'Model.User'
how to resolve that error line?
Here is my WebService.asmx :
[OperationContract]
public Model.User GetUser(string ccduser)
{
Model.User user = new Model.User();
string connectionString = ConfigurationManager.ConnectionStrings["ConnStr"].ConnectionString;
using (SqlConnection connection = new SqlConnection(connectionString)) {
string sql = "Select * from ms_webuser where ccduser = '" + ccduser + "'";
connection.Open();
SqlCommand command = new SqlCommand(sql, connection);
SqlDataReader reader = command.ExecuteReader();
while (reader.Read())
{
user.cnmuser = reader["cnmuser"].ToString();
}
}
MemoryStream stream = new MemoryStream();
DataContractJsonSerializer serializer = new DataContractJsonSerializer(typeof(Model.User));
serializer.WriteObject(stream, user);
stream.Position = 0;
StreamReader streamReader = new StreamReader(stream);
return streamReader.ReadToEnd(); //here is the error red line
}
Here is my Model.User Class:
namespace Model
{
public class User
{
private string _ccduser;
private string _cnmuser;
public string ccduser
{
get { return _ccduser; }
set { _ccduser = value; }
}
public string cnmuser
{
get { return _cnmuser; }
set { _cnmuser = value; }
}
}
}

You get that error because the ReadToEnd method returns a string and you have declared your method to return a Model.User
To resolve it you should return the user you want to return instead or you should change the method to return a string.