Add unit tests for tests/helpers.py to improve coverage (#9161)

Author: jalpuche1

tests/test_helpers_additional.py

@@ -0,0 +1,76 @@
+# mypy: disable-error-code="attr-defined"
+
+import os
+from pathlib import Path
+import pytest
+
+from poetry.utils import helpers
+
+
+def test_get_package_returns_package() -> None:
+    package = helpers.get_package("demo", "1.0.0")
+    assert package.name == "demo"
+    assert str(package.version) == "1.0.0"
+
+
+def test_with_working_directory_copy_and_remove(tmp_path: Path) -> None:
+    base_dir = tmp_path / "work"
+    base_dir.mkdir()
+    file = base_dir / "file.txt"
+    file.write_text("data")
+
+    with helpers.with_working_directory(base_dir):
+        assert Path("file.txt").exists()
+
+    assert not (Path.cwd() / "file.txt").exists()
+
+
+def test_pbs_installer_supported_arch_variants() -> None:
+    variants = helpers.pbs_installer_supported_arch_variants("x86_64")
+    assert "x86_64" in variants
+    assert "amd64" in variants
+
+
+def test_isolated_environment_adds_and_clears(tmp_path: Path) -> None:
+    env_dir = tmp_path / "env"
+    env_dir.mkdir()
+
+    with helpers.isolated_environment(env_dir):
+        assert Path.cwd() == env_dir
+
+    assert Path.cwd() != env_dir
+
+
+def test_flatten_dict_nested() -> None:
+    data = {"a": {"b": {"c": 1}}}
+    flat = helpers.flatten_dict(data)
+    assert flat == {"a.b.c": 1}
+
+
+def test_copy_path_file_and_dir(tmp_path: Path) -> None:
+    src_dir = tmp_path / "src"
+    dst_dir = tmp_path / "dst"
+    src_dir.mkdir()
+    file = src_dir / "test.txt"
+    file.write_text("hello")
+
+    helpers.copy_path(src_dir, dst_dir)
+    assert (dst_dir / "test.txt").exists()
+    assert (dst_dir / "test.txt").read_text() == "hello"
+
+
+def test_get_dependency_with_string_constraint() -> None:
+    dep = helpers.get_dependency("requests", "^2.0")
+    assert dep.name == "requests"
+    assert str(dep.constraint) == "^2.0"
+
+
+def test_switch_working_directory_creates_and_restores(tmp_path: Path) -> None:
+    original = Path.cwd()
+    new_dir = tmp_path / "work"
+    new_dir.mkdir()
+
+    with helpers.switch_working_directory(new_dir):
+        assert Path.cwd() == new_dir
+
+    assert Path.cwd() == original