From eae42740b69e3d055199d5268b86a52fa1181b6c Mon Sep 17 00:00:00 2001
From: Tim Head <betatim@gmail.com>
Date: Sat, 7 Sep 2019 23:05:14 +0200
Subject: [PATCH] Add tests for R version handling

---
 repo2docker/buildpacks/r.py |  3 +-
 tests/unit/test_r.py        | 95 +++++++++++++++++++++++++++++++++++++
 2 files changed, 97 insertions(+), 1 deletion(-)
 create mode 100644 tests/unit/test_r.py

diff --git a/repo2docker/buildpacks/r.py b/repo2docker/buildpacks/r.py
index 31072e2c..825901fe 100644
--- a/repo2docker/buildpacks/r.py
+++ b/repo2docker/buildpacks/r.py
@@ -214,7 +214,8 @@ class RBuildPack(PythonBuildPack):
         )
 
         scripts = []
-        # For R 3.4 we want to use the default Ubuntu package
+        # For R 3.4 we want to use the default Ubuntu package but otherwise
+        # we use the packages from a PPA
         if not self.r_version.startswith("3.4"):
             scripts += [
                 (
diff --git a/tests/unit/test_r.py b/tests/unit/test_r.py
new file mode 100644
index 00000000..a8bece97
--- /dev/null
+++ b/tests/unit/test_r.py
@@ -0,0 +1,95 @@
+from datetime import date
+
+import pytest
+
+from repo2docker import buildpacks
+
+
+@pytest.mark.parametrize(
+    "runtime_version, expected", [("", "3.6"), ("3.6", "3.6"), ("3.5.1", "3.5")]
+)
+def test_version_specification(tmpdir, runtime_version, expected):
+    tmpdir.chdir()
+
+    with open("runtime.txt", "w") as f:
+        if runtime_version:
+            runtime_version += "-"
+        f.write(f"r-{runtime_version}2019-01-01")
+
+    r = buildpacks.RBuildPack()
+    assert r.r_version.startswith(expected)
+
+
+def test_version_completion(tmpdir):
+    tmpdir.chdir()
+
+    with open("runtime.txt", "w") as f:
+        f.write(f"r-3.6-2019-01-01")
+
+    r = buildpacks.RBuildPack()
+    assert r.r_version == "3.6.1-3bionic"
+
+
+@pytest.mark.parametrize(
+    "runtime, expected",
+    [
+        ("r-2019-01-01", (2019, 1, 1)),
+        ("r-3.6.1-2019-01-01", (2019, 1, 1)),
+        ("r-3.5-2019-01-01", (2019, 1, 1)),
+    ],
+)
+def test_mran_date(tmpdir, runtime, expected):
+    tmpdir.chdir()
+
+    with open("runtime.txt", "w") as f:
+        f.write(runtime)
+
+    r = buildpacks.RBuildPack()
+    assert r.checkpoint_date == date(*expected)
+
+
+def test_install_from_base(tmpdir):
+    # check that for R==3.4 we install from ubuntu
+    tmpdir.chdir()
+
+    with open("runtime.txt", "w") as f:
+        f.write("r-3.4-2019-01-02")
+
+    r = buildpacks.RBuildPack()
+    assert "r-base" in r.get_packages()
+
+
+def test_install_from_ppa(tmpdir):
+    # check that for R>3.4 we don't install r-base from Ubuntu
+    tmpdir.chdir()
+
+    with open("runtime.txt", "w") as f:
+        f.write("r-3.5-2019-01-02")
+
+    r = buildpacks.RBuildPack()
+    assert "r-base" not in r.get_packages()
+
+
+def test_custom_ppa(tmpdir):
+    tmpdir.chdir()
+
+    with open("runtime.txt", "w") as f:
+        f.write("r-3.5-2019-01-02")
+
+    r = buildpacks.RBuildPack()
+
+    scripts = r.get_build_scripts()
+
+    # check that at least one of the build scripts adds this new PPA
+    for user, script in scripts:
+        if "https://cloud.r-project.org/bin/linux/ubuntu bionic-cran35/" in script:
+            break
+    else:
+        assert False, "Should have added a new PPA"
+
+    # check that we install the right package
+    for user, script in scripts:
+        if "r-base=3.5" in script:
+            break
+    else:
+        assert False, "Should have installed base R"