diff --git a/test/test_cli.py b/test/test_cli.py
deleted file mode 100644
index cae322a..0000000
--- a/test/test_cli.py
+++ /dev/null
@@ -1,7 +0,0 @@
-from topen import parse_cli
-
-
-class TestCli:
-    def test_cli_minimum_id(self, monkeypatch):
-        monkeypatch.setattr("sys.argv", ["topen", "42"])
-        assert parse_cli() == {"task_id": "42"}
diff --git a/test/test_configuration.py b/test/test_configuration.py
index b40223f..07ded09 100644
--- a/test/test_configuration.py
+++ b/test/test_configuration.py
@@ -30,3 +30,33 @@ class TestCli:
             "notes_editor": "vim",
             "notes_quiet": True,
         }
+
+
+@pytest.fixture
+def isolate_env(monkeypatch):
+    # delete all existing env vars that could interfere
+    for opt in OPTIONS.values():
+        if opt.env:
+            monkeypatch.delenv(opt.env, raising=False)
+
+
+class TestEnv:
+    def test_env_notes_ext(self, isolate_env, monkeypatch):
+        monkeypatch.setenv("TOPEN_NOTES_DIR", "/blablubb")
+        monkeypatch.setenv("TOPEN_NOTES_EXT", "rst")
+        monkeypatch.setenv("TOPEN_NOTES_ANNOT", "qmd")
+        monkeypatch.setenv("TOPEN_NOTES_EDITOR", "vim")
+        monkeypatch.setenv("TOPEN_NOTES_QUIET", "true")
+        env = parse_env()
+        assert env["notes_dir"] == Path("/blablubb")
+        assert env["notes_ext"] == "rst"
+        assert env["notes_annot"] == "qmd"
+        assert env["notes_editor"] == "vim"
+        assert env["notes_quiet"] is True
+
+    def test_env_task_rc(self, isolate_env, monkeypatch):
+        monkeypatch.setenv("TASKRC", "/a/dir/that/dont/exist/file")
+        monkeypatch.setenv("TASKDATA", "~/somewhere/tasks")
+        env = parse_env()
+        assert env["task_rc"] == Path("/a/dir/that/dont/exist/file")
+        assert env["task_data"] == Path("~/somewhere/tasks")