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?