Add R: prefix implementation and unit tests (#9)

Co-authored-by: Bernát Gábor <gaborjbernat@gmail.com>

README.md

@@ -8,7 +8,7 @@ versions](https://img.shields.io/pypi/pyversions/pytest-env.svg)](https://pypi.o
 black](https://img.shields.io/badge/code%20style-black-000000.svg)](https://github.com/psf/black)
 [![Downloads](https://pepy.tech/badge/pytest-env/month)](https://pepy.tech/project/pytest-env/month)
 
-This is a py.test plugin that enables you to set environment variables in the pytest.ini file.
+This is a `pytest` plugin that enables you to set environment variables in the pytest.ini file.
 
 ## Installation
 
@@ -20,7 +20,8 @@ pip install pytest-env
 
 ## Usage
 
-In your pytest.ini file add a key value pair with `env` as the key and the environment variables as a line separated list of `KEY=VALUE` entries.  The defined variables will be added to the environment before any tests are run:
+In your pytest.ini file add a key value pair with `env` as the key and the environment variables as a line separated
+list of `KEY=VALUE` entries. The defined variables will be added to the environment before any tests are run:
 
 ```ini
 [pytest]
@@ -29,6 +30,18 @@ env =
     RUN_ENV=test
 ```
 
+Or with `pyproject.toml`:
+
+```toml
+[tool.pytest.ini_options]
+env = [
+    "HOME=~/tmp",
+    "RUN_ENV=test",
+]
+```
+
+### Only set if not already set
+
 You can use `D:` (default) as prefix if you don't want to override existing environment variables:
 
 ```ini
@@ -38,10 +51,23 @@ env =
     D:RUN_ENV=test
 ```
 
-Lastly, you can use existing environment variables using a python-like format:
+### Transformation
+
+You can use existing environment variables using a python-like format, these environment variables will be expended
+before setting the environment variable:
 
 ```ini
 [pytest]
 env =
     RUN_PATH=/run/path/{USER}
 ```
+
+You can apply the `R:` prefix to keep the raw value and skip this transformation step (can combine with the `D:` flag,
+order is not important):
+
+```ini
+[pytest]
+env =
+    R:RUN_PATH=/run/path/{USER}
+    R:D:RUN_PATH_IF_NOT_SET=/run/path/{USER}
+```

src/pytest_env/plugin.py

@@ -8,8 +8,7 @@
 
 def pytest_addoption(parser: pytest.Parser) -> None:
     """Add section to configuration files."""
-    help_msg = "a line separated list of environment variables " "of the form NAME=VALUE."
-
+    help_msg = "a line separated list of environment variables of the form (FLAG:)NAME=VALUE"
     parser.addini("env", type="linelist", help=help_msg, default=[])
 
 
@@ -19,20 +18,19 @@ def pytest_load_initial_conftests(
 ) -> None:
     """Load environment variables from configuration files."""
     for line in early_config.getini("env"):
-        part = line.partition("=")
-        key = part[0].strip()
-        value = part[2].strip()
-
-        # Replace environment variables in value. for instance  TEST_DIR={USER}/repo_test_dir.
-        value = value.format(**os.environ)
-
-        # use D: as a way to designate a default value that will only override env variables if they do not exist
-        default_key = key.split("D:")
-        default_val = False
-
-        if len(default_key) == 2:
-            key = default_key[1]
-            default_val = True
 
-        if not default_val or key not in os.environ:
-            os.environ[key] = value
+        # INI lines e.g. D:R:NAME=VAL has two flags (R and D), NAME key, and VAL value
+        parts = line.partition("=")
+        ini_key_parts = parts[0].split(":")
+        flags = {k.strip().upper() for k in ini_key_parts[:-1]}
+        # R: is a way to designate whether to use raw value -> perform no transformation of the value
+        transform = "R" not in flags
+        # D: is a way to mark the value to be set only if it does not exist yet
+        skip_if_set = "D" in flags
+        key = ini_key_parts[-1].strip()
+        value = parts[2].strip()
+
+        if skip_if_set and key in os.environ:
+            continue
+        # transformation -> replace environment variables, e.g. TEST_DIR={USER}/repo_test_dir.
+        os.environ[key] = value.format(**os.environ) if transform else value

tests/template.py

@@ -0,0 +1,9 @@
+from __future__ import annotations
+
+import ast
+import os
+
+
+def test_env() -> None:
+    for key, value in ast.literal_eval(os.environ["_TEST_ENV"]).items():
+        assert os.environ[key] == value, key

tests/test_env.py

@@ -1,20 +1,106 @@
 from __future__ import annotations
 
+import os
+import re
 from pathlib import Path
+from unittest import mock
 
 import pytest
 
 
-@pytest.fixture()
-def example(testdir: pytest.Testdir) -> pytest.Testdir:
-    src = Path(__file__).parent / "example.py"
-    dest = Path(str(testdir.tmpdir / "test_example.py"))
-    dest.symlink_to(src)
-    return testdir
+@pytest.mark.parametrize(
+    ("env", "ini", "expected_env"),
+    [
+        pytest.param(
+            {},
+            "[pytest]\nenv = MAGIC=alpha",
+            {"MAGIC": "alpha"},
+            id="new key - add to env",
+        ),
+        pytest.param(
+            {},
+            "[pytest]\nenv = MAGIC=alpha\n SORCERY=beta",
+            {"MAGIC": "alpha", "SORCERY": "beta"},
+            id="two new keys - add to env",
+        ),
+        pytest.param(
+            # This test also tests for non-interference of env variables between this test and tests above
+            {},
+            "[pytest]\nenv = d:MAGIC=beta",
+            {"MAGIC": "beta"},
+            id="D flag - add to env",
+        ),
+        pytest.param(
+            {"MAGIC": "alpha"},
+            "[pytest]\nenv = MAGIC=beta",
+            {"MAGIC": "beta"},
+            id="key exists in env - overwrite",
+        ),
+        pytest.param(
+            {"MAGIC": "alpha"},
+            "[pytest]\nenv = D:MAGIC=beta",
+            {"MAGIC": "alpha"},
+            id="D exists - original val kept",
+        ),
+        pytest.param(
+            {"PLANET": "world"},
+            "[pytest]\nenv = MAGIC=hello_{PLANET}",
+            {"MAGIC": "hello_world"},
+            id="curly exist - interpolate var",
+        ),
+        pytest.param(
+            {"PLANET": "world"},
+            "[pytest]\nenv = R:MAGIC=hello_{PLANET}",
+            {"MAGIC": "hello_{PLANET}"},
+            id="R exists - not interpolate var",
+        ),
+        pytest.param(
+            {"MAGIC": "a"},
+            "[pytest]\nenv = R:MAGIC={MAGIC}b\n D:MAGIC={MAGIC}c\n MAGIC={MAGIC}d",
+            {"MAGIC": "{MAGIC}bd"},
+            id="incremental interpolation",
+        ),
+        pytest.param(
+            {"PLANET": "world"},
+            "[pytest]\nenv = D:R:RESULT=hello_{PLANET}",
+            {"RESULT": "hello_{PLANET}"},
+            id="two flags",
+        ),
+        pytest.param(
+            {"PLANET": "world"},
+            "[pytest]\nenv = R:D:RESULT=hello_{PLANET}",
+            {"RESULT": "hello_{PLANET}"},
+            id="two flags - reversed",
+        ),
+        pytest.param(
+            {"PLANET": "world"},
+            "[pytest]\nenv = d:r:RESULT=hello_{PLANET}",
+            {"RESULT": "hello_{PLANET}"},
+            id="lowercase flags",
+        ),
+        pytest.param(
+            {"PLANET": "world"},
+            "[pytest]\nenv =  D  :  R  :  RESULT  =  hello_{PLANET}",
+            {"RESULT": "hello_{PLANET}"},
+            id="whitespace is ignored",
+        ),
+        pytest.param(
+            {"MAGIC": "zero"},
+            "",
+            {"MAGIC": "zero"},
+            id="empty ini works",
+        ),
+    ],
+)
+def test_env(
+    testdir: pytest.Testdir, env: dict[str, str], ini: str, expected_env: dict[str, str], request: pytest.FixtureRequest
+) -> None:
+    test_name = re.sub(r"\W|^(?=\d)", "_", request.node.callspec.id).lower()
+    Path(str(testdir.tmpdir / f"test_{test_name}.py")).symlink_to(Path(__file__).parent / "template.py")
+    (testdir.tmpdir / "pytest.ini").write_text(ini, encoding="utf-8")
 
+    # monkeypatch persists env variables across parametrized tests, therefore using mock.patch.dict
+    with mock.patch.dict(os.environ, {**env, "_TEST_ENV": repr(expected_env)}, clear=True):
+        result = testdir.runpytest()
 
-def test_simple(example: pytest.Testdir) -> None:
-    (example.tmpdir / "pytest.ini").write_text("[pytest]\nenv = MAGIC=alpha", encoding="utf-8")
-    example.monkeypatch.setenv("_PATCH", "alpha")
-    result = example.runpytest()
     result.assert_outcomes(passed=1)

whitelist.txt

@@ -1,11 +1,12 @@
 addini
 addoption
+callspec
 conftests
 getini
 hookimpl
+parametrized
 repo
 runpytest
-setenv
 testdir
 tmpdir
 tryfirst