diff --git a/gnu/packages/cran.scm b/gnu/packages/cran.scm
index 2178a9175c5..1317e86c485 100644
--- a/gnu/packages/cran.scm
+++ b/gnu/packages/cran.scm
@@ -21134,7 +21134,8 @@ Bioconductor packages.")
      (list esbuild
            pkg-config
            r-knitr
-           r-rmarkdown))                ;for vignettes
+           r-rmarkdown                  ;for vignettes
+           r-testthat))
     (inputs
      (list freetype
            glu