Testing - open a testing workbook

[govert]

I think it would be nice to be able to run all the test from a class in the context of a pre-created workbook.
I'm trying to understand what the xUnit way to set this up would be.

For example, in the XFunctions add-in, I have some example workbooks:
https://github.com/Excel-DNA/XFunctions/tree/master/Examples
I want to make tests for the XFunctions add-in that execute in the context of one of those workbooks.

I suggest we add a WorkbookFixture class in the ExcelDna.Testing assembly that looks like this:

public class WorkbookFixture : IDisposable
{
    public Workbook Workbook { get; }

    public WorkbookFixture(string name)
    {
        // Look for the workbook in the test directory or somewhere close
        // not sure what the path search story should be - do we allow partial paths like testbook/myBook.xlsx ?
        // in practise one might want the test workbook in the test project directory, not the test output directory?
        // Anyway, once we've found it we open it.
    }
    public Dispose() {  // Close it? } 
}

For the test code, maybe something like this could then work.

Suppose there is a file called HelpExamples.xlsx in a good directory.
Then the test gets a class that subclasses the WorkbookFixture, passing in the name as constructor parameter.

public class HelpExamplesFixture : base("HelpExamples.xlsx") {}

public class HelpExampleTests : IClassFixture<HelpExamplesFixture>
{

    Workbook _wb;

    public HelpExampleTests(HelpExamplesFixture fixture) { _wb = fixture.Workbook; };

    [Fact]
    public void CheckSomething()
    {
        Assert.Equal(_wb.Range["A1"], 123);
    }     
}

@Sergey-Vlasov Do you have any thoughts on how this should work?

[Sergey-Vlasov]

We can now use Workbook attribute property on ExcelFact (method) or ExcelTestSettings (class) to automatically open and close a workbook file for a test. It can contain a relative path to a workbook file or an empty value to create a new workbook. ExcelDna.Testing.Util.Workbook provides access to the current workbook:

https://github.com/Excel-DNA/DeveloperTools/blob/master/ExcelDna.Testing/Examples/InProcessTests.cs
https://github.com/Excel-DNA/DeveloperTools/blob/master/ExcelDna.Testing/Examples/OutOfProcessTests.cs