Code Snippets

Commmon

• Thread Sleep v/s SpinWait

Thread.Sleep(500);
Thread.SpinWait(500);  // To keep the process in thread active rather than releasing it for another thread to execute

• Time Measurment

var start = System.Environment.TickCount;
// code 
var stop = System.Environment.TickCount;
var elapsedTimeInSeconds = (stop - start) / 1000.0;

Unit tests - NUnit

• For Exceptions

[TestMethod]
[ExpectedException(typeof(ArgumentException), "A userId of null was inappropriately allowed.")]
public void NullUserIdInConstructor()
{
   LogonInfo logonInfo = new LogonInfo(null, "P@ss0word");
}

• Multiple Data set

[Isolated]
[Test]
[TestCase(5)]
[TestCase(10)]
public void GetPeriodicityTest(int days)
{
  // test code
}

• Testing private Method

MyObject objUnderTest = new MyObject();
MethodInfo methodInfo = typeof(MyObject).GetMethod("SomePrivateMethod", BindingFlags.NonPublic | BindingFlags.Instance);
object[] parameters = {"parameters here"};
methodInfo.Invoke(objUnderTest, parameters);

• Testing Private Static Method

int days = 10;
string periodicity = "Invalid";
var privateTypeObject = new PrivateType(typeof(Employee));
object[] parameters = { days };
var actualPeriodicity = (string)privateTypeObject.InvokeStatic("GetPeriodicity", parameters);
actualPeriodicity.Should().Be(periodicity);

Manual Compilation of Csharp code using Rosyln

• Nuget package Microsoft.CodeAnalysis.CSharp

\\ A code.cs file has class "Greeter" and method "SayHello"

var code = File.readAllText("code.cs");
var tree = SyntaxFactory.ParseSyntaxTree(code);
var options = new CSharpCompilationOptions(OutputKind.DynamicallyLinkedLibrary);
var reference = new MetadataFileReference(typeof(object).Assembly.Location)

var compilation = CSharpCompilation.Create("test").WithOptions(options).AddSyntaxTrees(tree).AddReferences(reference);

var diagnostics = compilation.GetDiagnostics();
foreach (var diagnostic in diagnostics ) 
{
  System.Console.WriteLine(diagnostic.ToString());
}

using stream(var stream = new MemoryStream())
{
  compilation.Emit(stream);

  var assembly = Assembly.Load(stream.GetBuffer());
  var type = assembly.GetType("Greeter");
  var greeter = Activator.CreateInstance(type);
  var method = type.GetMethod("SayHello");
  method.Invoke(greeter, null);
}