ARROW-5919: [R] Test R-in-conda as a nightly build

Author: Uwe L. Korn <[email protected]>
Author: Uwe L. Korn <[email protected]>

Closes apache#4855 from xhochy/conda-r-docker and squashes the following commits:

b3189b863 <Uwe L. Korn> Add LICENSE to conda_env_r
971181dec <Uwe L. Korn> Add to nightlies
743aa5955 <Uwe L. Korn> Update Dockerfile.conda
b79e0c08e <Uwe L. Korn> ARROW-XXXX:  Test R-in-conda as a nightly build

Author: xhochy

ci/conda_env_r.yml

@@ -0,0 +1,36 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+r-assertthat
+r-base
+r-bit64
+r-fs
+r-purrr
+r-r6
+r-rcpp >=0.12.18.2
+r-rlang
+r-tidyselect
+# Test dependencies
+pandoc
+r-covr
+r-hms
+r-lubridate
+r-pkgdown
+r-rmarkdown
+r-roxygen2
+r-testthat
+r-tibble

dev/tasks/tests.yml

@@ -20,6 +20,7 @@ groups:
   # makes it easier to submit related tasks
   docker:
     - docker-r
+    - docker-r-conda
     - docker-rust
     - docker-cpp
     - docker-cpp-alpine
@@ -88,6 +89,16 @@ tasks:
         - docker-compose build r
         - docker-compose run r
 
+  docker-r-conda:
+    ci: circle
+    platform: linux
+    template: docker-tests/circle.linux.yml
+    params:
+      commands:
+        - docker-compose build cpp
+        - docker-compose build r-conda
+        - docker-compose run r-conda
+
   docker-rust:
     ci: circle
     platform: linux

docker-compose.yml

@@ -400,6 +400,21 @@ services:
       dockerfile: r/Dockerfile
     volumes: *ubuntu-volumes
 
+  r-conda:
+    # Usage:
+    #   export R_VERSION=3.5.1
+    #   docker-compose build cpp
+    #   docker-compose build r-conda
+    #   docker-compose run r-conda
+    image: arrow:r-conda-${R_VERSION:-3.5.1}
+    shm_size: 2G
+    build:
+      context: .
+      dockerfile: r/Dockerfile.conda
+      args:
+        R_VERSION: ${R_VERSION:-3.5.1}
+    volumes: *ubuntu-volumes
+
   ######################### Tools and Linters #################################
 
   # TODO(kszucs): site