Am I able to mock an output parameter

[tpeiffer]

Hello,

Given a function that executes a proc and returns the value of an output parameter, is it possible to Mock those parameters so that I can test that the method returns the correct value?

Given this method snippet in C#

var sproc = "dbo.usp_SomeProc";

var parameters = new DynamicParameters();
parameters.Add("@inParam", 100);
parameters.Add("@outParam", dbType: DbType.Int32, direction: ParameterDirection.Output);

await this.DbConnection
    .QueryAsync<int?>(sproc, parameters, commandType: CommandType.StoredProcedure);

return parameters.Get<int?>("outParam");

And this is where my test is at

// Arrange
var repository = this.CreateRepository();
var parameters = new DynamicParameters();
parameters.Add("@inParam", 100);
parameters.Add("@outParam", 999, DbType.Int32, ParameterDirection.Output);

var mockDbConnection = new MockDbConnection(new Settings() { ResetDapperCachePerCommand = true });
mockDbConnection
    .Setup(c => c.ExecuteAsync("dbo.usp_SomeProc", parameters, null, null, CommandType.StoredProcedure));

// Act
var result = await repository.Get(...);

// Assert
Assert.AreEqual(999, result);

Unfortunately, the test returns
Message: Assert.AreEqual failed. Expected:<999>. Actual:<(null)>.

I'm assuming that I need to mock more deeply into the command chain somehow.

Thanks for any guidance!

Thanks for your question, I'd need to investigate further. Without digging deeper I'm not sure if it would be possible.

Given what I know about how the library works I suspect it might be a challenge, if at all possible to achieve.

Simply put the act of the output parameter is normally a product of the SQL execution, not something which is predefined. I'll take a look as soon as I can