Requirement files support within deps

To support -r/-c/etc within deps we consider the deps section itself a
requirements file. We forward this as such to the installer. We validate
and traverse the entries within the requirements file, build the keys
so we know when we need to rebuild the tox environment. If only add
operation has been observed do not recreate the environment, bur rather
just update it with a new requirement file install.

Also added a mechanism into tox.pytest that allows enabling a short
circuit into the execute API. This is useful for example to auto
pass all install steps with success and a noop.

All install steps now have a run id starting with install. Run ids
have been altered to use the _ over the - as separator. This is to
bring it inline with how the PEP-517 backend uses the function name as
run it, and as such uses the _ as separator.

Fold legacy dev build requires package install into install-deps from a
dedicated step.

Signed-off-by: Bernát Gábor <bgabor8@bloomberg.net>

1 files changed, 34 insertions, 0 deletions

diff --git a/tests/tox_env/python/test_python_api.py b/tests/tox_env/python/test_python_api.py
index c7256d9f..93a4b04e 100644
--- a/tests/tox_env/python/test_python_api.py
+++ b/tests/tox_env/python/test_python_api.py
@@ -1,7 +1,9 @@
 from pathlib import Path
 
 from packaging.requirements import Requirement
+from pytest_mock import MockerFixture
 
+from tox.pytest import MonkeyPatch, ToxProjectCreator
 from tox.tox_env.python.api import PythonDep
 
 
@@ -32,3 +34,35 @@ def test_deps_req_ne() -> None:
 def test_deps_repr() -> None:
     dep_1 = PythonDep(Path.cwd())
     assert repr(dep_1) == f"PythonDep(value={Path.cwd()!r})"
+
+
+def test_requirements_txt(tox_project: ToxProjectCreator, monkeypatch: MonkeyPatch, mocker: MockerFixture) -> None:
+    prj = tox_project(
+        {
+            "tox.ini": "[testenv]\npackage=skip\ndeps=-rrequirements.txt",
+            "requirements.txt": "nose",
+        }
+    )
+    execute_calls = prj.patch_execute(lambda r: 0 if "install" in r.run_id else None)
+    result = prj.run("r", "-e", "py")
+    result.assert_success()
+    tox_env = result.state.tox_env("py")
+
+    assert execute_calls.call_count == 1
+    exp = [
+        str(tox_env.conf["env_python"]),
+        "-I",
+        "-m",
+        "pip",
+        "--disable-pip-version-check",
+        "install",
+        "-r",
+    ]
+    got_cmd = execute_calls.call_args[0][2].cmd
+
+    assert got_cmd[:-1] == exp
+
+    req = Path(got_cmd[-1])
+    assert req.parent == tox_env.core["tox_root"]
+    assert req.name.startswith("requirements-")
+    assert req.name.endswith(".txt")