Add test for parsing environment markers

tests/test_markers.py

@@ -0,0 +1,90 @@
+from pathlib import Path
+
+import pytest
+
+from conda_lock.src_parser import make_lock_spec
+
+
+ENVIRONMENT_YAML = """
+channels:
+    - conda-forge
+    - nodefaults
+dependencies:
+    - pip
+    - pip:
+        - cowsay; sys_platform == 'darwin'
+platforms:
+    - osx-64
+    - osx-arm64
+    - linux-64
+"""
+
+POETRY_PYPROJECT = """
+[tool.poetry]
+name = "conda-lock-test-poetry"
+version = "0.0.1"
+description = ""
+authors = ["conda-lock"]
+
+[tool.poetry.dependencies]
+python = "^3.9"
+cowsay = {version = "*", markers = "sys_platform == 'darwin'"}
+
+[build-system]
+requires = ["poetry>=0.12"]
+build-backend = "poetry.masonry.api"
+
+[tool.conda-lock]
+platforms = [
+    "osx-64",
+    "osx-arm64",
+    "linux-64",
+]
+"""
+
+HATCH_PYPROJECT = """
+[build-system]
+requires = ["hatchling >=1.25.0,<2"]
+build-backend = "hatchling.build"
+
+[project]
+name = "conda-lock-test-hatch"
+version = "0.0.1"
+dependencies = ["cowsay; sys_platform == 'darwin'"]
+
+[tool.conda-lock]
+platforms = [
+    "osx-64",
+    "osx-arm64",
+    "linux-64",
+]
+"""
+
+
+@pytest.fixture(
+    params=[
+        (ENVIRONMENT_YAML, "environment.yml"),
+        (POETRY_PYPROJECT, "pyproject.toml"),
+        (HATCH_PYPROJECT, "pyproject.toml"),
+    ],
+    ids=["environment.yml", "poetry", "hatch"],
+)
+def cowsay_src_file(request, tmp_path: Path):
+    contents, filename = request.param
+    src_file = tmp_path / filename
+    src_file.write_text(contents)
+    return src_file
+
+
+def test_sys_platform_marker(cowsay_src_file):
+    lock_spec = make_lock_spec(src_files=[cowsay_src_file])
+    dependencies = lock_spec.dependencies
+    platform_has_cowsay = {
+        platform: any(dep.name == "cowsay" for dep in platform_deps)
+        for platform, platform_deps in dependencies.items()
+    }
+    assert platform_has_cowsay == {
+        "osx-64": True,
+        "osx-arm64": True,
+        "linux-64": False,
+    }