add description test to this repo

docs/source/config_files.rst

@@ -117,7 +117,7 @@ To install your repository like an R package, you may include a
  from the ``DESCRIPTION`` by running ``devtools:install_git(".")``.
 
  You also need to have a ``runtime.txt`` file that is formatted as
- ``r-<YYYY>-<MM>-<DD>``, where YYYY-MM-DD is a snapshot at MRAN that will be
+ ``r-<YYYY>-<MM>-<DD>``, where YYYY-MM-DD is a snapshot of MRAN that will be
  used for your R installation.
 
 .. _postBuild:

tests/external/reproductions.repos.yaml

@@ -30,7 +30,3 @@
   url: https://github.com/QuantStack/xeus-cling
   ref: 0.4.5
   verify: jupyter kernelspec list
-- name: Test compiling R package
-  url: https://github.com/gedankenstuecke/binder-r-description
-  ref: master
-  verify: R --quiet -e 'binderdescription::print_something()'

tests/r/description-file/DESCRIPTION

@@ -0,0 +1,7 @@
+Package: binderdescription
+Version: 0.1
+Date: 2018-09-18
+Title: Binder R DESCRIPTION support
+Description: Test that automatically building R packages works
+Author: Bastian Greshake Tzovaras <bgreshake@googlemail.com>
+Maintainer: Bastian Greshake Tzovaras <bgreshake@googlemail.com>

tests/r/description-file/NAMESPACE

@@ -0,0 +1,2 @@
+# Export all names
+exportPattern(".")

tests/r/description-file/R/print_something.R

@@ -0,0 +1,4 @@
+print_something <- function()
+  {
+    print('blah');
+  }

tests/r/description-file/README.md

@@ -0,0 +1,4 @@
+# Test that `repo2docker` will build an R package
+
+If a `DESCRIPTION` file is present along with an `R`-requiring `runtime.txt`
+, repo2docker should build the R package that is in the repository.

tests/r/description-file/runtime.txt

@@ -0,0 +1 @@
+r-2018-02-05

tests/r/description-file/verify

@@ -0,0 +1,2 @@
+#!/usr/bin/env Rscript
+library('binderdescription')