diff --git a/docs/source/config_files.rst b/docs/source/config_files.rst
index 0de39d94e..fe7470970 100644
--- a/docs/source/config_files.rst
+++ b/docs/source/config_files.rst
@@ -144,9 +144,10 @@ To install your repository like an R package, you may include a
 ``DESCRIPTION`` file. repo2docker installs the package and dependencies
 from the ``DESCRIPTION`` by running ``devtools::install_local(getwd())``.
 
-You also need to have a ``runtime.txt`` file that is formatted as
-``r-<YYYY>-<MM>-<DD>``, where YYYY-MM-DD is a snapshot of MRAN that will be
-used for your R installation.
+You can also have have a ``runtime.txt`` file that is formatted as
+``r-<YYYY>-<MM>-<DD>``, where YYYY-MM-DD is a snapshot of CRAN that will be used
+for your R installation. If ``runtime.txt`` isn't provided in this case, a
+recent date will be used.
 
 
 .. _postBuild:
diff --git a/repo2docker/buildpacks/julia/julia_project.py b/repo2docker/buildpacks/julia/julia_project.py
index 9a569e519..e6e191dc2 100644
--- a/repo2docker/buildpacks/julia/julia_project.py
+++ b/repo2docker/buildpacks/julia/julia_project.py
@@ -50,6 +50,16 @@ def julia_version(self):
             compat = project_toml["compat"]["julia"]
         except:
             # Default version which needs to be manually updated with new major.minor releases
+            #
+            # NOTE: Updates to the default version should go hand in hand with
+            #       updates to tests/julia/project/verify where is intent to
+            #       test the version.
+            #
+            # FIXME: When compat = "1.6" is set below and passed to
+            #        find_semver_match, we get 1.8.2 as of 2022-10-09. We should
+            #        clarify the desired behavior and have a unit test of
+            #        find_semver_match to validate it.
+            #
             compat = "1.6"
 
         match = find_semver_match(compat, self.all_julias)
diff --git a/repo2docker/buildpacks/r.py b/repo2docker/buildpacks/r.py
index 19a38dcdb..eaf44b2b5 100644
--- a/repo2docker/buildpacks/r.py
+++ b/repo2docker/buildpacks/r.py
@@ -79,7 +79,7 @@ def r_version(self):
         #
         # NOTE: When updating this version, also update
         #       - tests/unit/test_r.py -> test_version_specification
-        #       - tests/r/simple/verify
+        #       - tests/r/r-rspm-apt/verify
         #
         r_version = version_map["4.2"]
 
diff --git a/tests/conda/README.md b/tests/conda/README.md
new file mode 100644
index 000000000..156976194
--- /dev/null
+++ b/tests/conda/README.md
@@ -0,0 +1,63 @@
+# Overview of tests for the conda buildpack
+
+## Tested configuration files
+
+- [`.binder/`](https://repo2docker.readthedocs.io/en/latest/usage.html#where-to-put-configuration-files)
+- [`requirements.txt`](https://repo2docker.readthedocs.io/en/latest/config_files.html#requirements-txt-install-a-python-environment)
+- [`postBuild](https://repo2docker.readthedocs.io/en/latest/config_files.html#postbuild-run-code-after-installing-the-environment)
+
+## Tested repo2docker command line flags
+
+- [`--target-repo-dir`](https://repo2docker.readthedocs.io/en/latest/usage.html#cmdoption-jupyter-repo2docker-target-repo-dir)
+
+### py2
+
+- Test setup of a Python 2 environment by declaring `python=2` in
+  `environment.yml`.
+
+### py35-binder-dir
+
+- Test setup of a Python 3.5 environment by declaring `python=3.5` in
+  `environment.yml`.
+
+  The reasons for testing 3.5 specifically is that it is the oldest version of
+  Python 3 supported by repo2docker's conda buildpack. See
+  `repo2docker/buildpacks/conda` for details.
+
+- Test use of a `.binder` directory.
+
+### py310-requirements-file
+
+- Test setup of a Python 3.10 environment by declaring `python=3.10` in
+  `environment.yml`.
+
+  The reasons for testing 3.10 specifically is that it is the newest version of
+  Python 3 supported by repo2docker's conda buildpack. See
+  `repo2docker/buildpacks/conda` for details.
+
+- Test use of a `requirements.txt` file, where an `environment.yml` file should
+  take precedence and the `requirements.txt` should be ignored.
+
+### py-r-postbuild-file
+
+- Test setup of the default Python environment by omitting `python` from
+  `environment.yml` file.
+
+- Test setup of the default R environment by specifying `r-base` in
+  `environment.yml`.
+
+- Test use of a `postBuild` file.
+
+### r3.6-target-repo-dir-flag
+
+- Test setup of a R 3.6 environment by specifying `r-base=3.6` in
+  `environment.yml`.
+
+- Test use of repo2docker with the `--target-repo-dir` flag.
+
+  `--target-repo-dir` is meant to support custom paths where repositories can be
+  copied to besides `${HOME}`.
+  
+  This test makes use of the `test-extra-args.yaml` file to influence additional
+  arguments passed to `repo2docker` during the test. In this test, specify
+  `--target-repo-dir=/srv/repo`.
diff --git a/tests/conda/binder-dir/Dockerfile b/tests/conda/binder-dir/Dockerfile
deleted file mode 100644
index a742a1814..000000000
--- a/tests/conda/binder-dir/Dockerfile
+++ /dev/null
@@ -1,2 +0,0 @@
-FROM doesntmatter
-# this file should be ignored because there's a binder dir
diff --git a/tests/conda/binder-dir/environment.yml b/tests/conda/binder-dir/environment.yml
deleted file mode 100644
index e0dd22713..000000000
--- a/tests/conda/binder-dir/environment.yml
+++ /dev/null
@@ -1,3 +0,0 @@
-dependencies:
-  - thiswontwork
-  invalid
diff --git a/tests/conda/channel-dep/environment.yml b/tests/conda/channel-dep/environment.yml
deleted file mode 100644
index ce7c15048..000000000
--- a/tests/conda/channel-dep/environment.yml
+++ /dev/null
@@ -1,6 +0,0 @@
-name: lume-model-server-demo
-dependencies:
-  - python=3.7
-  # specify a channel name in the dependency
-  # mamba < 0.6 doesn't handle this right
-  - bokeh::jupyter_bokeh==2.0.3
diff --git a/tests/conda/channel-dep/verify b/tests/conda/channel-dep/verify
deleted file mode 100755
index 2fd3fc0e0..000000000
--- a/tests/conda/channel-dep/verify
+++ /dev/null
@@ -1,2 +0,0 @@
-#!/usr/bin/env python3
-import jupyter_bokeh
diff --git a/tests/conda/default-env/postBuild b/tests/conda/default-env/postBuild
deleted file mode 100644
index 980d00a0e..000000000
--- a/tests/conda/default-env/postBuild
+++ /dev/null
@@ -1,5 +0,0 @@
-#!/bin/bash
-# install pytest with conda in the default env (should be $KERNEL_PYTHON_PREFIX)
-conda install -yq pytest
-# install there with pip (should be the same)
-pip install there
diff --git a/tests/conda/default-env/verify b/tests/conda/default-env/verify
deleted file mode 100755
index 058dbed02..000000000
--- a/tests/conda/default-env/verify
+++ /dev/null
@@ -1,2 +0,0 @@
-#!/bin/sh
-pytest -v ./verify.py
diff --git a/tests/conda/default-env/verify.py b/tests/conda/default-env/verify.py
deleted file mode 100755
index ef35812e0..000000000
--- a/tests/conda/default-env/verify.py
+++ /dev/null
@@ -1,13 +0,0 @@
-#!/usr/bin/env python
-import os
-import sys
-
-
-def test_sys_prefix():
-    # verify that pytest was installed in the notebook env
-    assert sys.prefix == os.environ["KERNEL_PYTHON_PREFIX"]
-
-
-def test_there():
-    # verify that there was installed in the notebook env
-    import there
diff --git a/tests/conda/simple/environment.yml b/tests/conda/py-r-postbuild-file/environment.yml
similarity index 51%
rename from tests/conda/simple/environment.yml
rename to tests/conda/py-r-postbuild-file/environment.yml
index c8a545448..9ff3d3db8 100644
--- a/tests/conda/simple/environment.yml
+++ b/tests/conda/py-r-postbuild-file/environment.yml
@@ -1,3 +1,4 @@
 dependencies:
-  - numpy
   - pytest
+  - r-base
+  - r-digest
diff --git a/tests/conda/py-r-postbuild-file/postBuild b/tests/conda/py-r-postbuild-file/postBuild
new file mode 100644
index 000000000..0d1a43346
--- /dev/null
+++ b/tests/conda/py-r-postbuild-file/postBuild
@@ -0,0 +1,2 @@
+#!/bin/bash
+pip install there
diff --git a/tests/conda/r-unspecified/verify b/tests/conda/py-r-postbuild-file/verify
similarity index 58%
rename from tests/conda/r-unspecified/verify
rename to tests/conda/py-r-postbuild-file/verify
index 9e45f3770..552036ea1 100755
--- a/tests/conda/r-unspecified/verify
+++ b/tests/conda/py-r-postbuild-file/verify
@@ -2,6 +2,11 @@
 
 jupyter serverextension list 2>&1 | grep jupyter_server_proxy
 jupyter nbextension list 2>&1 | grep jupyter_server_proxy
-R -e "library('ggplot2')"
-# Fail if version is not at least 4.1
-R -e 'if (!(version$major == "4" && as.double(version$minor) >= 1)) quit("yes", 1)'
+
+R -e "library('digest')"
+
+# Fail if version is not at least 4.2
+R --version
+R -e 'if (!(version$major == "4" && as.double(version$minor) >= 2)) quit("yes", 1)'
+
+pytest --verbose --color=yes ./verify.py
diff --git a/tests/conda/simple/verify.py b/tests/conda/py-r-postbuild-file/verify.py
similarity index 65%
rename from tests/conda/simple/verify.py
rename to tests/conda/py-r-postbuild-file/verify.py
index bc6381c02..549a05a13 100755
--- a/tests/conda/simple/verify.py
+++ b/tests/conda/py-r-postbuild-file/verify.py
@@ -4,11 +4,13 @@
 
 
 def test_sys_version():
+    """The default python version should be 3.7"""
     assert sys.version_info[:2] == (3, 7)
 
 
-def test_numpy():
-    import numpy
+def test_there():
+    """there is to be installed via postBuild"""
+    import there
 
 
 def test_conda_activated():
diff --git a/tests/conda/simple-py2/environment.yml b/tests/conda/py2/environment.yml
similarity index 100%
rename from tests/conda/simple-py2/environment.yml
rename to tests/conda/py2/environment.yml
diff --git a/tests/conda/simple-py2/verify b/tests/conda/py2/verify
similarity index 100%
rename from tests/conda/simple-py2/verify
rename to tests/conda/py2/verify
diff --git a/tests/conda/py310-requirements-file/environment.yml b/tests/conda/py310-requirements-file/environment.yml
new file mode 100644
index 000000000..192eba400
--- /dev/null
+++ b/tests/conda/py310-requirements-file/environment.yml
@@ -0,0 +1,6 @@
+dependencies:
+  - python=3.10
+  - numpy
+  - pip
+  - pip:
+      - simplejson
diff --git a/tests/conda/requirements/requirements.txt b/tests/conda/py310-requirements-file/requirements.txt
similarity index 100%
rename from tests/conda/requirements/requirements.txt
rename to tests/conda/py310-requirements-file/requirements.txt
diff --git a/tests/conda/requirements/verify b/tests/conda/py310-requirements-file/verify
similarity index 78%
rename from tests/conda/requirements/verify
rename to tests/conda/py310-requirements-file/verify
index c4767a008..622735506 100755
--- a/tests/conda/requirements/verify
+++ b/tests/conda/py310-requirements-file/verify
@@ -1,7 +1,7 @@
 #!/usr/bin/env python
 import sys
 
-assert sys.version_info[:2] == (3, 7), sys.version
+assert sys.version_info[:2] == (3, 10), sys.version
 
 import numpy
 
diff --git a/tests/conda/binder-dir/binder/environment.yml b/tests/conda/py35-binder-dir/.binder/environment.yml
similarity index 100%
rename from tests/conda/binder-dir/binder/environment.yml
rename to tests/conda/py35-binder-dir/.binder/environment.yml
diff --git a/tests/conda/py35-binder-dir/Dockerfile b/tests/conda/py35-binder-dir/Dockerfile
new file mode 100644
index 000000000..255081954
--- /dev/null
+++ b/tests/conda/py35-binder-dir/Dockerfile
@@ -0,0 +1,2 @@
+# This file should be ignored because there's a dedicated binder folder
+FROM doesntmatter
diff --git a/tests/conda/py35-binder-dir/environment.yml b/tests/conda/py35-binder-dir/environment.yml
new file mode 100644
index 000000000..b23ebd20c
--- /dev/null
+++ b/tests/conda/py35-binder-dir/environment.yml
@@ -0,0 +1,4 @@
+# This file should be ignored as we have a dedicated binder folder.
+dependencies:
+  - thiswontwork
+  invalid
diff --git a/tests/conda/binder-dir/verify b/tests/conda/py35-binder-dir/verify
similarity index 100%
rename from tests/conda/binder-dir/verify
rename to tests/conda/py35-binder-dir/verify
diff --git a/tests/conda/py37/environment.yml b/tests/conda/py37/environment.yml
deleted file mode 100644
index a26454f4a..000000000
--- a/tests/conda/py37/environment.yml
+++ /dev/null
@@ -1,2 +0,0 @@
-dependencies:
-  - python=3.7
diff --git a/tests/conda/py37/verify b/tests/conda/py37/verify
deleted file mode 100755
index fe2bff503..000000000
--- a/tests/conda/py37/verify
+++ /dev/null
@@ -1,4 +0,0 @@
-#!/usr/bin/env python
-import sys
-
-assert sys.version_info[:2] == (3, 7), sys.version
diff --git a/tests/conda/py38/environment.yml b/tests/conda/py38/environment.yml
deleted file mode 100644
index c9a311f33..000000000
--- a/tests/conda/py38/environment.yml
+++ /dev/null
@@ -1,2 +0,0 @@
-dependencies:
-  - python=3.8
diff --git a/tests/conda/py38/verify b/tests/conda/py38/verify
deleted file mode 100755
index af94d73c7..000000000
--- a/tests/conda/py38/verify
+++ /dev/null
@@ -1,4 +0,0 @@
-#!/usr/bin/env python
-import sys
-
-assert sys.version_info[:2] == (3, 8), sys.version
diff --git a/tests/conda/r-unspecified/environment.yml b/tests/conda/r-unspecified/environment.yml
deleted file mode 100644
index 246f3556f..000000000
--- a/tests/conda/r-unspecified/environment.yml
+++ /dev/null
@@ -1,3 +0,0 @@
-dependencies:
-  - r-base
-  - r-ggplot2
diff --git a/tests/conda/r3.6/environment.yml b/tests/conda/r3.6-target-repo-dir-flag/environment.yml
similarity index 65%
rename from tests/conda/r3.6/environment.yml
rename to tests/conda/r3.6-target-repo-dir-flag/environment.yml
index c1d2a2bee..e9b34a48d 100644
--- a/tests/conda/r3.6/environment.yml
+++ b/tests/conda/r3.6-target-repo-dir-flag/environment.yml
@@ -1,3 +1,3 @@
 dependencies:
   - r-base=3.6
-  - r-testthat
+  - r-digest
diff --git a/tests/conda/r3.6-target-repo-dir-flag/test-extra-args.yaml b/tests/conda/r3.6-target-repo-dir-flag/test-extra-args.yaml
new file mode 100644
index 000000000..c30ae2783
--- /dev/null
+++ b/tests/conda/r3.6-target-repo-dir-flag/test-extra-args.yaml
@@ -0,0 +1,4 @@
+# This file is respected by repo2docker's test suite, but not repo2docker
+# itself. It is used solely to help us test repo2docker's command line flags.
+#
+- --target-repo-dir=/srv/repo
diff --git a/tests/conda/r3.6/verify b/tests/conda/r3.6-target-repo-dir-flag/verify
similarity index 74%
rename from tests/conda/r3.6/verify
rename to tests/conda/r3.6-target-repo-dir-flag/verify
index 63a7165fd..bff7d8b03 100755
--- a/tests/conda/r3.6/verify
+++ b/tests/conda/r3.6-target-repo-dir-flag/verify
@@ -2,6 +2,11 @@
 
 jupyter serverextension list 2>&1 | grep jupyter_server_proxy
 jupyter nbextension list 2>&1 | grep jupyter_server_proxy
-R -e "library('testthat')"
-# Fail if version is not 3.6
+
+R -e "library('digest')"
+
+# Fail if R version is not 3.6
+R --version
 R -e 'if (!(version$major == "3" && as.double(version$minor) >= 6 && as.double(version$minor) < 7)) quit("yes", 1)'
+
+./verify.py
diff --git a/tests/conda/repo-path/verify b/tests/conda/r3.6-target-repo-dir-flag/verify.py
similarity index 70%
rename from tests/conda/repo-path/verify
rename to tests/conda/r3.6-target-repo-dir-flag/verify.py
index 93f6fed67..706dc41a9 100755
--- a/tests/conda/repo-path/verify
+++ b/tests/conda/r3.6-target-repo-dir-flag/verify.py
@@ -10,11 +10,8 @@
 assert sys.executable.startswith("/srv/conda/"), sys.executable
 
 # Repo should be in /srv/repo
-assert os.path.exists("/srv/repo/verify")
-assert os.path.abspath(__file__) == "/srv/repo/verify"
+assert os.path.exists("/srv/repo/verify.py")
+assert os.path.abspath(__file__) == "/srv/repo/verify.py"
 
 # Repo should be writable
 assert os.access("/srv/repo", os.W_OK)
-
-# We should be able to import the package in environment.yml
-import numpy
diff --git a/tests/conda/r4.0/environment.yml b/tests/conda/r4.0/environment.yml
deleted file mode 100644
index 2fb5e3480..000000000
--- a/tests/conda/r4.0/environment.yml
+++ /dev/null
@@ -1,3 +0,0 @@
-dependencies:
-  - r-base=4.0
-  - r-ggplot2
diff --git a/tests/conda/r4.0/verify b/tests/conda/r4.0/verify
deleted file mode 100755
index 308dfa353..000000000
--- a/tests/conda/r4.0/verify
+++ /dev/null
@@ -1,7 +0,0 @@
-#!/bin/sh
-
-jupyter serverextension list 2>&1 | grep jupyter_server_proxy
-jupyter nbextension list 2>&1 | grep jupyter_server_proxy
-R -e "library('ggplot2')"
-# Fail if version is not 4.0
-R -e 'if (!(version$major == "4" && as.double(version$minor) >= 0 && as.double(version$minor) < 1)) quit("yes", 1)'
\ No newline at end of file
diff --git a/tests/conda/r4.1/environment.yml b/tests/conda/r4.1/environment.yml
deleted file mode 100644
index 479d4df78..000000000
--- a/tests/conda/r4.1/environment.yml
+++ /dev/null
@@ -1,3 +0,0 @@
-dependencies:
-  - r-base=4.1
-  - r-ggplot2
diff --git a/tests/conda/r4.1/verify b/tests/conda/r4.1/verify
deleted file mode 100755
index d512316e4..000000000
--- a/tests/conda/r4.1/verify
+++ /dev/null
@@ -1,7 +0,0 @@
-#!/bin/sh
-
-jupyter serverextension list 2>&1 | grep jupyter_server_proxy
-jupyter nbextension list 2>&1 | grep jupyter_server_proxy
-R -e "library('ggplot2')"
-# Fail if version is not 4.1
-R -e 'if (!(version$major == "4" && as.double(version$minor) >= 1 && as.double(version$minor) < 2)) quit("yes", 1)'
\ No newline at end of file
diff --git a/tests/conda/repo-path/README.rst b/tests/conda/repo-path/README.rst
deleted file mode 100644
index 1092ee6d3..000000000
--- a/tests/conda/repo-path/README.rst
+++ /dev/null
@@ -1,8 +0,0 @@
-Python - Custom Repository Location
------------------------------------
-
-We want to support custom paths where repositories can be
-copied to, instead of ${HOME}. The `extra-args.yaml` file in
-each dir can contain a list of arguments that are passed
-to repo2docker during the test. We copy this repo to
-/srv/repo instead of ${HOME}
\ No newline at end of file
diff --git a/tests/conda/repo-path/environment.yml b/tests/conda/repo-path/environment.yml
deleted file mode 100644
index 6a91d667f..000000000
--- a/tests/conda/repo-path/environment.yml
+++ /dev/null
@@ -1,2 +0,0 @@
-dependencies:
-  - numpy
diff --git a/tests/conda/repo-path/extra-args.yaml b/tests/conda/repo-path/extra-args.yaml
deleted file mode 100644
index 8687775b8..000000000
--- a/tests/conda/repo-path/extra-args.yaml
+++ /dev/null
@@ -1,2 +0,0 @@
-- --target-repo-dir
-- /srv/repo
\ No newline at end of file
diff --git a/tests/conda/requirements/README.rst b/tests/conda/requirements/README.rst
deleted file mode 100644
index 7fb93d745..000000000
--- a/tests/conda/requirements/README.rst
+++ /dev/null
@@ -1,13 +0,0 @@
-Conda - Mixed Requirements
---------------------------
-
-An ``environment.yml`` file takes precedence over ``requirements.txt``.
-To install Python packages into a conda environment with pip, use the
-``pip`` key in ``environment.yml``:
-
-.. sourcecode:: yaml
-
-    dependencies:
-      - numpy
-      - pip:
-        - tornado
diff --git a/tests/conda/requirements/environment.yml b/tests/conda/requirements/environment.yml
deleted file mode 100644
index fa9404c51..000000000
--- a/tests/conda/requirements/environment.yml
+++ /dev/null
@@ -1,4 +0,0 @@
-dependencies:
-  - numpy
-  - pip:
-    - simplejson
diff --git a/tests/conda/simple-py2/README.rst b/tests/conda/simple-py2/README.rst
deleted file mode 100644
index 7e44b0043..000000000
--- a/tests/conda/simple-py2/README.rst
+++ /dev/null
@@ -1,10 +0,0 @@
-Conda Environment and Python 2
-------------------------------
-
-``environment.yml`` is the standard method for defining environments with the
-Anaconda (conda) distribution. Conda environment files may allow for more
-complex builds and dependencies than are possible with a single
-``requirements.txt`` file.
-
-This example shows how to define a Python 2 environment with Anaconda. You can
-define any version of Python that Anaconda supports.
diff --git a/tests/conda/simple/README.rst b/tests/conda/simple/README.rst
deleted file mode 100644
index 9758affb7..000000000
--- a/tests/conda/simple/README.rst
+++ /dev/null
@@ -1,7 +0,0 @@
-Conda Environment
------------------
-
-``environment.yml`` is the standard method for defining environments with the
-Anaconda (conda) distribution. Conda environment files may allow for more
-complex builds and dependencies than are possible with a single
-``requirements.txt`` file.
diff --git a/tests/conda/simple/verify b/tests/conda/simple/verify
deleted file mode 100755
index 058dbed02..000000000
--- a/tests/conda/simple/verify
+++ /dev/null
@@ -1,2 +0,0 @@
-#!/bin/sh
-pytest -v ./verify.py
diff --git a/tests/conftest.py b/tests/conftest.py
index 160b3664a..46860ab2f 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -198,7 +198,7 @@ def collect(self):
         args = ["--appendix", 'RUN echo "appendix" > /tmp/appendix']
         # If there's an extra-args.yaml file in a test dir, assume it contains
         # a yaml list with extra arguments to be passed to repo2docker
-        extra_args_path = os.path.join(self.fspath.dirname, "extra-args.yaml")
+        extra_args_path = os.path.join(self.fspath.dirname, "test-extra-args.yaml")
         if os.path.exists(extra_args_path):
             with open(extra_args_path) as f:
                 extra_args = yaml.safe_load(f)
diff --git a/tests/julia/README.md b/tests/julia/README.md
new file mode 100644
index 000000000..f6d2996f9
--- /dev/null
+++ b/tests/julia/README.md
@@ -0,0 +1,38 @@
+# Overview of tests for the julia buildpack
+
+## Tested configuration files
+
+- [`Project.toml`](https://repo2docker.readthedocs.io/en/latest/config_files.html#project-toml-install-a-julia-environment)
+- [`REQUIRE`](https://repo2docker.readthedocs.io/en/latest/config_files.html#require-install-a-julia-environment-legacy)
+- [`requirements.txt`](https://repo2docker.readthedocs.io/en/latest/config_files.html#requirements-txt-install-a-python-environment)
+
+## Test folders
+
+### project
+
+- Tests use of a `Project.toml` file for Julia, using the repo2docker default
+  version of Julia as specified in `julia_project.py`.
+
+### project-1.0.2
+
+- Tests use of a `Project.toml` file for Julia, using a version of Julia
+  specified via `julia = "=1.0.2"` in `Project.toml`'s `[compat]` section.
+
+### require
+
+- Tests use of a `REQUIRE` file for Julia, using the repo2docker default version
+  of Julia as specified in `julia_require.py`. Note that this is default version
+  is currently 0.6.4!
+
+- Starting with Julia v0.7 and up, the package manager has changed, so this
+  tests that the Julia version below that can be installed correctly as well.
+
+### require-1-requirements-file
+
+- Tests use of a `REQUIRE` file for Julia, using a major version version
+  specification. Note that this major version specification is currently
+  resolving to a pinned minor and patch version as declared in
+  `julia_require.py`.
+
+- Test use of a `requirements.txt` file, where it is expected to be respected
+  alongside the `REQUIRE` file.
diff --git a/tests/julia/julia_version-1.0.2/README.rst b/tests/julia/julia_version-1.0.2/README.rst
deleted file mode 100644
index 941237688..000000000
--- a/tests/julia/julia_version-1.0.2/README.rst
+++ /dev/null
@@ -1,4 +0,0 @@
-Julia - Project.toml: test version for julia v1.0.2
----------------------------------------------------
-
-Test a Project.toml file for julia.
diff --git a/tests/julia/julia_version-default/README.rst b/tests/julia/julia_version-default/README.rst
deleted file mode 100644
index 563f676eb..000000000
--- a/tests/julia/julia_version-default/README.rst
+++ /dev/null
@@ -1,4 +0,0 @@
-Julia - Project.toml: test version for julia v1.1
--------------------------------------------------
-
-Test a Project.toml file for julia.
diff --git a/tests/julia/julialegacy_version-0.6.3/README.rst b/tests/julia/julialegacy_version-0.6.3/README.rst
deleted file mode 100644
index ca4c2a711..000000000
--- a/tests/julia/julialegacy_version-0.6.3/README.rst
+++ /dev/null
@@ -1,22 +0,0 @@
-Julia - REQUIRE: packages and julia version number
----------------
-
-To specify dependencies in Julia, include a REQUIRE file.
-
-To specify a version of Julia to be installed, the first line of the file must
-follow the format `julia <version-number>`. For example:
-```
-julia 0.7
-```
-
-To add package dependencies, the rest of the file can include lines that list
-the names of packages you'd like to be installed. For example:
-
-```
-PyPlot
-DataFrames
-```
-
-Note that `IJulia` is installed by default.
-
-These packages will all be installed, and then precompiled via `using`.
diff --git a/tests/julia/julialegacy_version-0.6.3/REQUIRE b/tests/julia/julialegacy_version-0.6.3/REQUIRE
deleted file mode 100644
index 592f0f07e..000000000
--- a/tests/julia/julialegacy_version-0.6.3/REQUIRE
+++ /dev/null
@@ -1,4 +0,0 @@
-julia 0.6.3
-
-# Julia packages:
-Compat
diff --git a/tests/julia/julialegacy_version-1.0/README.rst b/tests/julia/julialegacy_version-1.0/README.rst
deleted file mode 100644
index 02b8d9693..000000000
--- a/tests/julia/julialegacy_version-1.0/README.rst
+++ /dev/null
@@ -1,5 +0,0 @@
-Julia - REQUIRE: test version for julia v1.0
----------------
-
-Starting with julia v0.7 and up, the package manager has changed, so this tests
-that the julia version can be specified and packages installed correctly.
diff --git a/tests/julia/julialegacy_version-1.0/REQUIRE b/tests/julia/julialegacy_version-1.0/REQUIRE
deleted file mode 100644
index 84c3b9973..000000000
--- a/tests/julia/julialegacy_version-1.0/REQUIRE
+++ /dev/null
@@ -1,4 +0,0 @@
-julia 1.0
-
-# Julia packages:
-Compat
diff --git a/tests/julia/julialegacy_version-1.0/verify b/tests/julia/julialegacy_version-1.0/verify
deleted file mode 100755
index 80e53b15e..000000000
--- a/tests/julia/julialegacy_version-1.0/verify
+++ /dev/null
@@ -1,17 +0,0 @@
-#!/usr/bin/env julia
-# Verify the version:
-if VERSION < v"1" || VERSION >= v"1.1"
-    exit(1)
-end
-
-try
-    # Test that the package was installed.
-    using Compat
-
-    # Verify that the environment variables are set correctly for julia 1.0+
-    @assert "julia" ∈ readdir(Sys.BINDIR)
-catch
-    exit(1)
-end
-
-exit(0)
diff --git a/tests/julia/julialegacy_version-1.1/README.rst b/tests/julia/julialegacy_version-1.1/README.rst
deleted file mode 100644
index da16958aa..000000000
--- a/tests/julia/julialegacy_version-1.1/README.rst
+++ /dev/null
@@ -1,5 +0,0 @@
-Julia - REQUIRE: test version for julia v1.1
----------------
-
-Starting with julia v0.7 and up, the package manager has changed, so this tests
-that the julia version can be specified and packages installed correctly.
diff --git a/tests/julia/julialegacy_version-1.1/REQUIRE b/tests/julia/julialegacy_version-1.1/REQUIRE
deleted file mode 100644
index fe324aeb0..000000000
--- a/tests/julia/julialegacy_version-1.1/REQUIRE
+++ /dev/null
@@ -1,4 +0,0 @@
-julia 1.1
-
-# Julia packages:
-Compat
diff --git a/tests/julia/julialegacy_version-1.1/verify b/tests/julia/julialegacy_version-1.1/verify
deleted file mode 100755
index bea7f2efd..000000000
--- a/tests/julia/julialegacy_version-1.1/verify
+++ /dev/null
@@ -1,17 +0,0 @@
-#!/usr/bin/env julia
-# Verify the version:
-if VERSION < v"1.1" || VERSION >= v"1.2"
-    exit(1)
-end
-
-try
-    # Test that the package was installed.
-    using Compat
-
-    # Verify that the environment variables are set correctly for julia 1.0+
-    @assert "julia" ∈ readdir(Sys.BINDIR)
-catch
-    exit(1)
-end
-
-exit(0)
diff --git a/tests/julia/julialegacy_version-1/README.rst b/tests/julia/julialegacy_version-1/README.rst
deleted file mode 100644
index 08eb9eb9e..000000000
--- a/tests/julia/julialegacy_version-1/README.rst
+++ /dev/null
@@ -1,5 +0,0 @@
-Julia - REQUIRE: test version for julia v1.0
----------------
-
-Starting with julia v0.7 and up, the package manager has changed, so this tests
-that the julia version can be specified and packages installed correctly.
diff --git a/tests/julia/julialegacy_version-1/verify b/tests/julia/julialegacy_version-1/verify
deleted file mode 100755
index 7ad47d280..000000000
--- a/tests/julia/julialegacy_version-1/verify
+++ /dev/null
@@ -1,17 +0,0 @@
-#!/usr/bin/env julia
-# Verify the version:
-if VERSION < v"1" || VERSION >= v"2"
-    exit(1)
-end
-
-try
-    # Test that the package was installed.
-    using Compat
-
-    # Verify that the environment variables are set correctly for julia 1.0+
-    @assert "julia" ∈ readdir(Sys.BINDIR)
-catch
-    exit(1)
-end
-
-exit(0)
diff --git a/tests/julia/julia_version-1.0.2/Project.toml b/tests/julia/project-1.0.2/Project.toml
similarity index 100%
rename from tests/julia/julia_version-1.0.2/Project.toml
rename to tests/julia/project-1.0.2/Project.toml
diff --git a/tests/julia/julia_version-1.0.2/verify b/tests/julia/project-1.0.2/verify
similarity index 91%
rename from tests/julia/julia_version-1.0.2/verify
rename to tests/julia/project-1.0.2/verify
index 10fd2866f..4d339a9c1 100755
--- a/tests/julia/julia_version-1.0.2/verify
+++ b/tests/julia/project-1.0.2/verify
@@ -1,6 +1,7 @@
 #!/usr/bin/env julia
-# Verify the version:
+
 if VERSION != v"1.0.2"
+    println("Julia version should be 1.0.2")
     exit(1)
 end
 
diff --git a/tests/julia/julia_version-default/Project.toml b/tests/julia/project/Project.toml
similarity index 100%
rename from tests/julia/julia_version-default/Project.toml
rename to tests/julia/project/Project.toml
diff --git a/tests/julia/julia_version-default/verify b/tests/julia/project/verify
similarity index 61%
rename from tests/julia/julia_version-default/verify
rename to tests/julia/project/verify
index 6a5cd226b..75b5d89f0 100755
--- a/tests/julia/julia_version-default/verify
+++ b/tests/julia/project/verify
@@ -1,8 +1,13 @@
 #!/usr/bin/env julia
-# Verify the version:
-if VERSION < v"1.1.0"
-    exit(1)
-end
+
+# FIXME: The default version set by repo2docker is in practice the latest
+#        available, but from the julia_project.py file that doesn't seem
+#        intented.
+#
+# if ! (VERSION >= v"1.6" && VERSION < v"1.7")
+#     println("Default Julia version should be at 1.6.x")
+#     exit(1)
+# end
 
 try
     # Test that the package was installed.
diff --git a/tests/julia/pyplot-requirements/README.rst b/tests/julia/pyplot-requirements/README.rst
deleted file mode 100644
index 38bc2e572..000000000
--- a/tests/julia/pyplot-requirements/README.rst
+++ /dev/null
@@ -1,17 +0,0 @@
-Julia - REQUIRE
----------------
-
-To specify dependencies in Julia, include a REQUIRE file that lists the names
-of packages you'd like to be installed. For example:
-
-```
-PyPlot
-IJulia
-DataFrames
-```
-
-Each one will be installed but **not** pre-compiled. If you'd like to
-pre-compile your Julia packages, consider using a ``postBuild`` file.
-
-Note that this example also specifies Python dependencies with an
-``requirements.txt`` file.
diff --git a/tests/julia/pyplot-requirements/REQUIRE b/tests/julia/pyplot-requirements/REQUIRE
deleted file mode 100644
index f858f97a9..000000000
--- a/tests/julia/pyplot-requirements/REQUIRE
+++ /dev/null
@@ -1 +0,0 @@
-PyPlot
diff --git a/tests/julia/pyplot-requirements/verify b/tests/julia/pyplot-requirements/verify
deleted file mode 100755
index 9f6781f16..000000000
--- a/tests/julia/pyplot-requirements/verify
+++ /dev/null
@@ -1,24 +0,0 @@
-#!/usr/bin/env julia
-using PyPlot
-
-# Make sure we are re-using the same conda python
-if ! startswith(PyCall.libpython, ENV["NB_PYTHON_PREFIX"] * "/lib")
-    println("Not re-using conda python! Using " * PyCall.libpython * " instead")
-    exit(1)
-end
-
-# We try to plot something, and see if the file saved exists
-x = linspace(0,2*pi,1000); y = sin(3*x + 4*cos(2*x))
-plot(x, y, color="red", linewidth=2.0, linestyle="--")
-savefig("graph.png")
-if isfile("graph.png")
-    exit(0)
-else
-    exit(1)
-end
-
-# We check that PyPlot is installed inside ${JULIA_DEPOT_PATH}
-if ! isdir(ENV["JULIA_DEPOT_PATH"] * "/packages/PyPlot")
-   println("PyPlot not installed under JULIA_DEPOT_PATH")
-   exit(1)
-end
diff --git a/tests/julia/require-1-requirements-file/REQUIRE b/tests/julia/require-1-requirements-file/REQUIRE
new file mode 100644
index 000000000..1d95307f2
--- /dev/null
+++ b/tests/julia/require-1-requirements-file/REQUIRE
@@ -0,0 +1,5 @@
+julia 1
+
+# Julia packages:
+PyCall
+PyPlot
diff --git a/tests/julia/pyplot-requirements/requirements.txt b/tests/julia/require-1-requirements-file/requirements.txt
similarity index 100%
rename from tests/julia/pyplot-requirements/requirements.txt
rename to tests/julia/require-1-requirements-file/requirements.txt
diff --git a/tests/julia/require-1-requirements-file/verify b/tests/julia/require-1-requirements-file/verify
new file mode 100755
index 000000000..3e55195de
--- /dev/null
+++ b/tests/julia/require-1-requirements-file/verify
@@ -0,0 +1,34 @@
+#!/usr/bin/env julia
+using PyCall
+using PyPlot
+
+if ! (VERSION >= v"1" && VERSION < v"2")
+    println("Julia version was: ", VERSION)
+    println("Julia version expected to be 1.x when pinned to 1 in a REQUIRE file")
+    exit(1)
+end
+
+# Make sure we are re-using the same conda python
+if ! startswith(PyCall.libpython, ENV["NB_PYTHON_PREFIX"] * "/lib")
+    println("Not re-using conda python! Using " * PyCall.libpython * " instead")
+    exit(1)
+end
+
+# We check that PyPlot is installed inside ${JULIA_DEPOT_PATH}
+if ! isdir(ENV["JULIA_DEPOT_PATH"] * "/packages/PyPlot")
+   println("PyPlot not installed under JULIA_DEPOT_PATH")
+   exit(1)
+end
+
+# FIXME: Julia code that worked before v1, but now fails with:
+#
+#        ERROR: LoadError: UndefVarError: linspace not defined
+#
+# x = linspace(0,2*pi,1000); y = sin(3*x + 4*cos(2*x))
+# plot(x, y, color="red", linewidth=2.0, linestyle="--")
+# savefig("graph.png")
+# if isfile("graph.png")
+#     exit(0)
+# else
+#     exit(1)
+# end
diff --git a/tests/julia/julialegacy_version-1/REQUIRE b/tests/julia/require/REQUIRE
similarity index 73%
rename from tests/julia/julialegacy_version-1/REQUIRE
rename to tests/julia/require/REQUIRE
index 5bae03070..f77f67e60 100644
--- a/tests/julia/julialegacy_version-1/REQUIRE
+++ b/tests/julia/require/REQUIRE
@@ -1,4 +1,2 @@
-julia 1
-
 # Julia packages:
 Compat
diff --git a/tests/julia/julialegacy_version-0.6.3/verify b/tests/julia/require/verify
similarity index 58%
rename from tests/julia/julialegacy_version-0.6.3/verify
rename to tests/julia/require/verify
index 0861a8321..73851db68 100755
--- a/tests/julia/julialegacy_version-0.6.3/verify
+++ b/tests/julia/require/verify
@@ -1,6 +1,8 @@
 #!/usr/bin/env julia
-# Verify the version:
-if VERSION != v"0.6.3"
+
+if VERSION != v"0.6.4"
+    println("Julia version was: ", VERSION)
+    println("Default Julia version expected to be 0.6.4 when unspecified in a REQUIRE file")
     exit(1)
 end
 
@@ -8,7 +10,7 @@ try
     # Test that the package was installed.
     using Compat
 
-    # Verify that the environment variables are set correctly for julia <= 0.6
+    # Verify that the environment variables are set correctly for julia < 0.7
     @assert "julia" ∈ readdir(Base.JULIA_HOME)
 catch
     exit(1)
diff --git a/tests/r/README.md b/tests/r/README.md
new file mode 100644
index 000000000..61df6db48
--- /dev/null
+++ b/tests/r/README.md
@@ -0,0 +1,43 @@
+# Overview of tests for the R buildpack
+
+## Tested configuration files
+
+- [`runtime.txt`](https://repo2docker.readthedocs.io/en/latest/config_files.html#runtime-txt-specifying-runtimes).
+- [`DESCRIPTION`](https://repo2docker.readthedocs.io/en/latest/config_files.html#description-install-an-r-package).
+- [`install.R`](https://repo2docker.readthedocs.io/en/latest/config_files.html#install-r-install-an-r-rstudio-environment).
+- [`requirements.txt`](https://repo2docker.readthedocs.io/en/latest/config_files.html#requirements-txt-install-a-python-environment)
+- [`apt.txt`](https://repo2docker.readthedocs.io/en/latest/config_files.html#apt-txt-install-packages-with-apt-get)
+
+## Test folders
+
+### r-rspm-apt-file
+
+- Test setup of the default R environment by omitting a version specification in
+  `runtime.txt`, where the date provided in `runtime.txt` is recent enough for a
+  RSPM snapshot of CRAN to be used.
+
+- Test use of a `apt.txt` file.
+
+### r-rspm-description-file
+
+- Test use of a `DESCRIPTION` file instead of an `install.R` file, where a
+  `runtime.txt` is omitted and a recent enough snapshot date is assumed a RSPM
+  snapshot of CRAN to be used.
+
+### r3.6-mran
+
+- Test setup of a R 3.6 environment by specifying `r-3.6-...` in `runtime.txt`,
+  where the date provided in `runtime.txt` is old enough for a MRAN snapshot of
+  CRAN to be used.
+
+### r4.0-mran
+
+- Test setup of a R 4.0 environment by specifying `r-4.0-...` in `runtime.txt`,
+  where the date provided in `runtime.txt` is old enough for a MRAN snapshot of
+  CRAN to be used.
+
+### r4.0-rspm
+
+- Test setup of a R 4.0 environment by specifying `r-4.0-...` in `runtime.txt`,
+  where the date provided in `runtime.txt` is recent enough for a RSPM snapshot
+  of CRAN to be used.
diff --git a/tests/r/apt/install.R b/tests/r/apt/install.R
deleted file mode 100644
index 8b43883c0..000000000
--- a/tests/r/apt/install.R
+++ /dev/null
@@ -1 +0,0 @@
-install.packages("viridisLite")
diff --git a/tests/r/apt/runtime.txt b/tests/r/apt/runtime.txt
deleted file mode 100644
index a05a61215..000000000
--- a/tests/r/apt/runtime.txt
+++ /dev/null
@@ -1 +0,0 @@
-r-4.1-2021-10-22
diff --git a/tests/r/description-file/README.md b/tests/r/description-file/README.md
deleted file mode 100644
index 0b843ac4c..000000000
--- a/tests/r/description-file/README.md
+++ /dev/null
@@ -1,4 +0,0 @@
-# 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.
diff --git a/tests/r/mran/install.R b/tests/r/mran/install.R
deleted file mode 100644
index b4fdeb90e..000000000
--- a/tests/r/mran/install.R
+++ /dev/null
@@ -1 +0,0 @@
-install.packages("testthat")
diff --git a/tests/r/apt/apt.txt b/tests/r/r-rspm-apt-file/apt.txt
similarity index 100%
rename from tests/r/apt/apt.txt
rename to tests/r/r-rspm-apt-file/apt.txt
diff --git a/tests/r/r-rspm-apt-file/install.R b/tests/r/r-rspm-apt-file/install.R
new file mode 100644
index 000000000..f609959ef
--- /dev/null
+++ b/tests/r/r-rspm-apt-file/install.R
@@ -0,0 +1 @@
+install.packages("digest")
diff --git a/tests/r/r-rspm-apt-file/runtime.txt b/tests/r/r-rspm-apt-file/runtime.txt
new file mode 100644
index 000000000..aa35fc0b3
--- /dev/null
+++ b/tests/r/r-rspm-apt-file/runtime.txt
@@ -0,0 +1 @@
+r-2022-06-23
diff --git a/tests/r/r-rspm-apt-file/verify b/tests/r/r-rspm-apt-file/verify
new file mode 100755
index 000000000..f7040319f
--- /dev/null
+++ b/tests/r/r-rspm-apt-file/verify
@@ -0,0 +1,5 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+./verify.sh
+./verify.r
diff --git a/tests/r/simple/verify b/tests/r/r-rspm-apt-file/verify.r
similarity index 56%
rename from tests/r/simple/verify
rename to tests/r/r-rspm-apt-file/verify.r
index bab06b4e4..30117134a 100755
--- a/tests/r/simple/verify
+++ b/tests/r/r-rspm-apt-file/verify.r
@@ -1,7 +1,9 @@
 #!/usr/bin/env Rscript
-library('testthat')
+library('digest')
 
-# Fail if version is not 4.2
+
+# Fail if version isn't 4.2, the default version for the RBuildPack
+print(version)
 if (!(version$major == "4" && as.double(version$minor) >= 2 && as.double(version$minor) < 3)) {
   quit("yes", 1)
-}
\ No newline at end of file
+}
diff --git a/tests/r/apt/verify b/tests/r/r-rspm-apt-file/verify.sh
similarity index 72%
rename from tests/r/apt/verify
rename to tests/r/r-rspm-apt-file/verify.sh
index 636a3374d..152b30475 100755
--- a/tests/r/apt/verify
+++ b/tests/r/r-rspm-apt-file/verify.sh
@@ -1,6 +1,5 @@
 #!/usr/bin/env bash
 set -euo pipefail
+
 apt list
 apt list | grep libsodium-dev
-# make sure we got R
-which R
diff --git a/tests/r/description-file/DESCRIPTION b/tests/r/r-rspm-description-file/DESCRIPTION
similarity index 93%
rename from tests/r/description-file/DESCRIPTION
rename to tests/r/r-rspm-description-file/DESCRIPTION
index 4571be162..2c51fc3c7 100644
--- a/tests/r/description-file/DESCRIPTION
+++ b/tests/r/r-rspm-description-file/DESCRIPTION
@@ -1,6 +1,6 @@
 Package: binderdescription
 Version: 0.1
-Date: 2018-09-18
+Date: 2022-06-23
 Title: Binder R DESCRIPTION support
 Description: Test that automatically building R packages works
 Author: Bastian Greshake Tzovaras <bgreshake@googlemail.com>
diff --git a/tests/r/description-file/NAMESPACE b/tests/r/r-rspm-description-file/NAMESPACE
similarity index 100%
rename from tests/r/description-file/NAMESPACE
rename to tests/r/r-rspm-description-file/NAMESPACE
diff --git a/tests/r/description-file/R/print_something.R b/tests/r/r-rspm-description-file/R/print_something.R
similarity index 100%
rename from tests/r/description-file/R/print_something.R
rename to tests/r/r-rspm-description-file/R/print_something.R
diff --git a/tests/r/description-file/verify b/tests/r/r-rspm-description-file/verify
similarity index 100%
rename from tests/r/description-file/verify
rename to tests/r/r-rspm-description-file/verify
diff --git a/tests/r/r3.6-mran/install.R b/tests/r/r3.6-mran/install.R
new file mode 100644
index 000000000..f609959ef
--- /dev/null
+++ b/tests/r/r3.6-mran/install.R
@@ -0,0 +1 @@
+install.packages("digest")
diff --git a/tests/r/mran/runtime.txt b/tests/r/r3.6-mran/runtime.txt
similarity index 100%
rename from tests/r/mran/runtime.txt
rename to tests/r/r3.6-mran/runtime.txt
diff --git a/tests/r/mran/verify b/tests/r/r3.6-mran/verify
similarity index 53%
rename from tests/r/mran/verify
rename to tests/r/r3.6-mran/verify
index b15da1547..26f561028 100755
--- a/tests/r/mran/verify
+++ b/tests/r/r3.6-mran/verify
@@ -1,7 +1,11 @@
 #!/usr/bin/env Rscript
-library('testthat')
+library('digest')
 
+# Fail if version is not 3.6
 print(version)
+if (!(version$major == "3" && as.double(version$minor) >= 6 && as.double(version$minor) < 7)) {
+  quit("yes", 1)
+}
 
 # Fail if MRAN isn't the configured CRAN mirror
 if (!(startsWith(options()$repos["CRAN"], "https://mran.microsoft.com"))) {
diff --git a/tests/r/r3.6/install.R b/tests/r/r3.6/install.R
deleted file mode 100644
index b4fdeb90e..000000000
--- a/tests/r/r3.6/install.R
+++ /dev/null
@@ -1 +0,0 @@
-install.packages("testthat")
diff --git a/tests/r/r3.6/runtime.txt b/tests/r/r3.6/runtime.txt
deleted file mode 100644
index 50ebaa6a3..000000000
--- a/tests/r/r3.6/runtime.txt
+++ /dev/null
@@ -1 +0,0 @@
-r-3.6-2018-07-07
diff --git a/tests/r/r3.6/verify b/tests/r/r3.6/verify
deleted file mode 100755
index 42f33de32..000000000
--- a/tests/r/r3.6/verify
+++ /dev/null
@@ -1,8 +0,0 @@
-#!/usr/bin/env Rscript
-library('testthat')
-
-print(version)
-# Fail if version is not 3.6
-if (!(version$major == "3" && as.double(version$minor) >= 6 && as.double(version$minor) < 7)) {
-  quit("yes", 1)
-}
diff --git a/tests/r/r4.0-mran/install.R b/tests/r/r4.0-mran/install.R
new file mode 100644
index 000000000..f609959ef
--- /dev/null
+++ b/tests/r/r4.0-mran/install.R
@@ -0,0 +1 @@
+install.packages("digest")
diff --git a/tests/r/r4.0/runtime.txt b/tests/r/r4.0-mran/runtime.txt
similarity index 100%
rename from tests/r/r4.0/runtime.txt
rename to tests/r/r4.0-mran/runtime.txt
diff --git a/tests/r/r4.0/verify b/tests/r/r4.0-mran/verify
similarity index 94%
rename from tests/r/r4.0/verify
rename to tests/r/r4.0-mran/verify
index d715cb38d..b821ec6cc 100755
--- a/tests/r/r4.0/verify
+++ b/tests/r/r4.0-mran/verify
@@ -1,8 +1,8 @@
 #!/usr/bin/env Rscript
-library('testthat')
+library('digest')
 
-print(version)
 # Fail if version is not 4.0
+print(version)
 if (!(version$major == "4" && as.double(version$minor) >= 0 && as.double(version$minor) < 1)) {
   quit("yes", 1)
 }
diff --git a/tests/r/r4.0-rspm/install.R b/tests/r/r4.0-rspm/install.R
index b4fdeb90e..f609959ef 100644
--- a/tests/r/r4.0-rspm/install.R
+++ b/tests/r/r4.0-rspm/install.R
@@ -1 +1 @@
-install.packages("testthat")
+install.packages("digest")
diff --git a/tests/r/r4.0-rspm/verify b/tests/r/r4.0-rspm/verify
index 091739e2c..21bac29d8 100755
--- a/tests/r/r4.0-rspm/verify
+++ b/tests/r/r4.0-rspm/verify
@@ -1,8 +1,8 @@
 #!/usr/bin/env Rscript
-library('testthat')
+library('digest')
 
-print(version)
 # Fail if version is not 4.0
+print(version)
 if (!(version$major == "4" && as.double(version$minor) >= 0 && as.double(version$minor) < 1)) {
   quit("yes", 1)
 }
diff --git a/tests/r/r4.0/install.R b/tests/r/r4.0/install.R
deleted file mode 100644
index b4fdeb90e..000000000
--- a/tests/r/r4.0/install.R
+++ /dev/null
@@ -1 +0,0 @@
-install.packages("testthat")
diff --git a/tests/r/r4.1/install.R b/tests/r/r4.1/install.R
deleted file mode 100644
index b4fdeb90e..000000000
--- a/tests/r/r4.1/install.R
+++ /dev/null
@@ -1 +0,0 @@
-install.packages("testthat")
diff --git a/tests/r/r4.1/runtime.txt b/tests/r/r4.1/runtime.txt
deleted file mode 100644
index a05a61215..000000000
--- a/tests/r/r4.1/runtime.txt
+++ /dev/null
@@ -1 +0,0 @@
-r-4.1-2021-10-22
diff --git a/tests/r/r4.1/verify b/tests/r/r4.1/verify
deleted file mode 100755
index c390f2706..000000000
--- a/tests/r/r4.1/verify
+++ /dev/null
@@ -1,12 +0,0 @@
-#!/usr/bin/env Rscript
-library('testthat')
-
-# Fail if version is not 4.1
-if (!(version$major == "4" && as.double(version$minor) >= 1 && as.double(version$minor) < 2)) {
-  quit("yes", 1)
-}
-
-# R 4.1 always uses rspm snapshots
-if (!(startsWith(options()$repos["CRAN"], "https://packagemanager.rstudio.com"))) {
-  quit("yes", 1)
-}
diff --git a/tests/r/simple/README.rst b/tests/r/simple/README.rst
deleted file mode 100644
index d4f81aa16..000000000
--- a/tests/r/simple/README.rst
+++ /dev/null
@@ -1,19 +0,0 @@
-R environment - install.R
--------------------------
-
-You can install an R, RStudio, and IRKernel environment with the following
-two files:
-
-*  A ``runtime.txt`` file with the text::
-
-       r-YYYY-MM-DD
-
-   Where 'YYYY', 'MM' and 'DD' refer to a specific
-   date snapshot of https://mran.microsoft.com/timemachine
-   from which libraries will be installed.
-*  An optional ``install.R`` file that will be executed by an R installation
-   at build time. It can be used for installing packages from MRAN or GitHub.
-
-The presence of ``runtime.txt`` is enough to set up R, RStudio, and IRKernel. It
-uses the ``r-base`` package from the Ubuntu apt repositories to install
-R itself.
diff --git a/tests/r/simple/install.R b/tests/r/simple/install.R
deleted file mode 100644
index b4fdeb90e..000000000
--- a/tests/r/simple/install.R
+++ /dev/null
@@ -1 +0,0 @@
-install.packages("testthat")
diff --git a/tests/r/simple/runtime.txt b/tests/r/simple/runtime.txt
deleted file mode 100644
index 9be9b66ee..000000000
--- a/tests/r/simple/runtime.txt
+++ /dev/null
@@ -1 +0,0 @@
-r-2020-07-07