Simple Data Access in C#

using System;
using System.Data;

using Microsoft.VisualStudio.TestTools.UnitTesting;

using Yap.Data.Client;


namespace Yap.Data.UnitTest
{
	[TestClass]
	public class CommandTestFixture
	{
		[TestMethod]
		public void Constructor_Default_PropertiesShouldBeInitializedWithDefaultValues()
		{
			Command command = new DummyCommand();
			Assert.AreEqual(String.Empty, command.Text, "Command.Text should be String.Empty by default.");
			Assert.AreEqual(String.Empty, command.Description, "Command.Description should be String.Empty by default.");
			Assert.IsNotNull(command.Parameters, "Command.Parameters collection should be initialized by default.");
		}

		[TestMethod]
		[ExpectedException(typeof(InvalidOperationException))]
		public void Execute_TextIsEmpty_ThrowInvalidOperationException()
		{
			Command command = new DummyCommand {Text = String.Empty};
			command.Execute();
		}

		[TestMethod]
		public void Equals_OtherIsNull_ReturnFalse()
		{
			Command command = new DummyCommand();
			Assert.IsFalse(command.Equals(null), "Equals() with null should return false.");
		}

		[TestMethod]
		public void Equals_FullTest()
		{
			Command one = new DummyCommand();
			Command another = new DummyCommand();
			Assert.AreEqual(one, another, "Equals() with equal command should return true.");
			one.Text = "differs";
			Assert.AreNotEqual(one, another, "Equals() with not equal command should return false.");
			one.Text = another.Text = null;
			Assert.AreEqual(one, another, "Equals() with equal command should return true.");
			one.Text = another.Text = "SELECT * FROM dual";
			Assert.AreEqual(one, another, "Equals() with equal command should return true.");
			one.Description = "differs";
			Assert.AreNotEqual(one, another, "Equals() with not equal command should return false.");
			one.Description = another.Description = null;
			Assert.AreEqual(one, another, "Equals() with equal command should return true.");
			one.Description = another.Description = "description";
			Assert.AreEqual(one, another, "Equals() with equal command should return true.");
			one.Parameters.Add("differs", null);
			Assert.AreNotEqual(one, another, "Equals() with not equal command should return false.");
			one.Parameters.Clear();
			Assert.AreEqual(one, another, "Equals() with equal command should return true.");
			one.Parameters.Add("differs", null);
			another.Parameters.Add("differs", "not null");
			Assert.AreNotEqual(one, another, "Equals() with not equal command should return false.");
			one.Parameters.Clear();
			another.Parameters.Clear();
			Assert.AreEqual(one, another, "Equals() with equal command should return true.");
			one.Parameters.Add("first", "first value");
			one.Parameters.Add("second", "second value");
			another.Parameters.Add("second", "second value");
			another.Parameters.Add("first", "first value");
			Assert.AreEqual(one, another, "Equals() with equal command should return true.");
		}

		[TestMethod]
		public void ToString__ShouldBeEqualToText()
		{
			Command command = new DummyCommand();
			Assert.AreEqual(command.Text, command.ToString(), "ToString() should be equal to Command.Text.");
			command.Text = "SELECT * FROM dual";
			Assert.AreEqual(command.Text, command.ToString(), "ToString() should be equal to Command.Text.");
			command.Text = null;
			Assert.AreEqual(command.Text, command.ToString(), "ToString() should be equal to Command.Text.");
		}

		[TestMethod]
		public void GetHashCode_TextIsEmpty_ShouldBeEqualTo0()
		{
			Command command = new DummyCommand();
			Assert.AreEqual(0, command.GetHashCode(), "GetHashCode() should be 0 if Command.Text is empty.");
		}

		[TestMethod]
		public void GetHashCode_TextIsNotEmpty_ShouldBeEqualToTextGetHashCode()
		{
			Command command = new DummyCommand {Text = "SELECT * FROM dual"};
			Assert.AreEqual(command.Text.GetHashCode(), command.GetHashCode(), "GetHashCode() should be equal to Command.Text.GetHashCode() if Command.Text is not empty.");
		}
	}

	public class DummyCommand : Command
	{
		protected override void Execute(IDbCommand command, IDatabaseProvider provider)
		{
			throw new NotImplementedException();
		}
	}

}