public void CreateExpressionTest1()
{
// Arrange
Expression parameterExpression = Expression.Parameter(typeof(Employee), "sample");
Expression expressionProperty = Expression.Property(parameterExpression, nameof(Employee.Subordinates));
Expression expressionConstant = Expression.Constant(2);
MethodInfo methodInfo = typeof(Enumerable).GetMethods()
.First(method => method.Name == "Count" && method.GetParameters().Length == 1)
.MakeGenericMethod(typeof(object));
var expressionCount = Expression.Call(methodInfo, expressionProperty);
Expression expectedExpression = Expression.Equal(expressionCount, expressionConstant);
var _operator = new CountOperator();
// Act
Expression resultExpression = _operator.CreateExpression(expressionProperty, expressionConstant);
// Assert
Assert.AreEqual(expectedExpression.ToString(), resultExpression.ToString(), "Expression not correct");
}
