Ensure tests pass without dependencies cached from previous tests

Adds a --cache-dir arg to the compile cli and uses it for test isolation
via monkeypatching of consumed env var

piptools/cache.py

@@ -8,7 +8,6 @@
 from pip._vendor.packaging.requirements import Requirement
 
 from .exceptions import PipToolsError
-from .locations import CACHE_DIR
 from .utils import as_tuple, key_from_req, lookup_table
 
 
@@ -49,9 +48,7 @@ class DependencyCache(object):
     Where X.Y indicates the Python version.
     """
 
-    def __init__(self, cache_dir=None):
-        if cache_dir is None:
-            cache_dir = CACHE_DIR
+    def __init__(self, cache_dir):
         if not os.path.isdir(cache_dir):
             os.makedirs(cache_dir)
         py_version = ".".join(str(digit) for digit in sys.version_info[:2])

piptools/repositories/pypi.py

@@ -26,9 +26,9 @@
     path_to_url,
     url_to_path,
 )
-from ..cache import CACHE_DIR
 from ..click import progressbar
 from ..exceptions import NoCandidateFound
+from ..locations import CACHE_DIR
 from ..logging import log
 from ..utils import (
     create_install_command,

piptools/resolver.py

@@ -8,7 +8,6 @@
 
 from . import click
 from ._compat import install_req_from_line
-from .cache import DependencyCache
 from .logging import log
 from .utils import (
     UNSAFE_PACKAGES,
@@ -95,7 +94,7 @@ def __init__(
         self,
         constraints,
         repository,
-        cache=None,
+        cache,
         prereleases=False,
         clear_caches=False,
         allow_unsafe=False,
@@ -108,8 +107,6 @@ def __init__(
         self.our_constraints = set(constraints)
         self.their_constraints = set()
         self.repository = repository
-        if cache is None:
-            cache = DependencyCache()  # pragma: no cover
         self.dependency_cache = cache
         self.prereleases = prereleases
         self.clear_caches = clear_caches

piptools/scripts/compile.py

@@ -9,7 +9,9 @@
 
 from .. import click
 from .._compat import install_req_from_line, parse_requirements
+from ..cache import DependencyCache
 from ..exceptions import PipToolsError
+from ..locations import CACHE_DIR
 from ..logging import log
 from ..repositories import LocalRequirementsRepository, PyPIRepository
 from ..resolver import Resolver
@@ -172,6 +174,15 @@
     default=True,
     help="Add the find-links option to generated file",
 )
+@click.option(
+    "--cache-dir",
+    help="Specify a directory to cache dependency information (defaults to {})".format(
+        CACHE_DIR
+    ),
+    envvar="PIP_TOOLS_CACHE_DIR",
+    show_envvar=True,
+    type=click.Path(file_okay=False, writable=True),
+)
 def cli(
     ctx,
     verbose,
@@ -198,6 +209,7 @@ def cli(
     max_rounds,
     build_isolation,
     emit_find_links,
+    cache_dir,
 ):
     """Compiles requirements.txt from requirements.in specs."""
     log.verbosity = verbose - quiet
@@ -348,11 +360,15 @@ def cli(
         for find_link in dedup(repository.finder.find_links):
             log.debug("  -f {}".format(find_link))
 
+    if cache_dir is None:
+        cache_dir = CACHE_DIR
+
     try:
         resolver = Resolver(
             constraints,
             repository,
             prereleases=repository.finder.allow_all_prereleases or pre,
+            cache=DependencyCache(cache_dir),
             clear_caches=rebuild,
             allow_unsafe=allow_unsafe,
         )

piptools/utils.py

@@ -20,6 +20,7 @@
     "--upgrade",
     "--upgrade-package",
     "--verbose",
+    "--cache-dir",
 }
 
 

tests/test_cli_compile.py

@@ -15,6 +15,11 @@
 from piptools.scripts.compile import cli
 
 
+@pytest.fixture(autouse=True)
+def temp_dep_cache(tmpdir, monkeypatch):
+    monkeypatch.setenv("PIP_TOOLS_CACHE_DIR", str(tmpdir / "cache"))
+
+
 def test_default_pip_conf_read(pip_with_index_conf, runner):
     # preconditions
     with open("requirements.in", "w"):
@@ -519,7 +524,7 @@ def test_generate_hashes_verbose(pip_conf, runner):
 
 
 @pytest.mark.skipif(PIP_VERSION < (9,), reason="needs pip 9 or greater")
-def test_filter_pip_markers(runner):
+def test_filter_pip_markers(pip_conf, runner):
     """
     Check that pip-compile works with pip environment markers (PEP496)
     """
@@ -592,7 +597,7 @@ def test_not_specified_input_file(runner):
     assert out.exit_code == 2
 
 
-def test_stdin(runner):
+def test_stdin(pip_conf, runner):
     """
     Test compile requirements from STDIN.
     """