Bug#1102331: r-cran-sparsevctrs: missing test-depends on r-cran-matrix

[Rebecca N. Palmer]

Package: r-cran-sparsevctrs
Version: 0.2.0-1
Severity: serious
Tags: patch
The autopkgtest is failing with

Error in `coerce_to_sparse_matrix(mtcars)`: The package "Matrix" is 
required.

(I'm not sure why this is only now actually failing, when it's always 
had that error message: possibly a recently fixed bug in r-cran-testthat.)

The obvious fix is to add that package (r-cran-matrix?) to 
debian/tests/control.