Move InstallationCandidate to models + add tests

src/pip/_internal/index.py

@@ -28,6 +28,7 @@ from pip._internal.exceptions import (
     UnsupportedWheel,
 )
 from pip._internal.models.index import PyPI
+from pip._internal.models.candidate import InstallationCandidate
 from pip._internal.pep425tags import get_supported
 from pip._internal.utils.deprecation import RemovedInPip11Warning
 from pip._internal.utils.logging import indent_log
@@ -57,47 +58,6 @@ SECURE_ORIGINS = [
 logger = logging.getLogger(__name__)
 
 
-class InstallationCandidate(object):
-
-    def __init__(self, project, version, location):
-        self.project = project
-        self.version = parse_version(version)
-        self.location = location
-        self._key = (self.project, self.version, self.location)
-
-    def __repr__(self):
-        return "<InstallationCandidate({!r}, {!r}, {!r})>".format(
-            self.project, self.version, self.location,
-        )
-
-    def __hash__(self):
-        return hash(self._key)
-
-    def __lt__(self, other):
-        return self._compare(other, lambda s, o: s < o)
-
-    def __le__(self, other):
-        return self._compare(other, lambda s, o: s <= o)
-
-    def __eq__(self, other):
-        return self._compare(other, lambda s, o: s == o)
-
-    def __ge__(self, other):
-        return self._compare(other, lambda s, o: s >= o)
-
-    def __gt__(self, other):
-        return self._compare(other, lambda s, o: s > o)
-
-    def __ne__(self, other):
-        return self._compare(other, lambda s, o: s != o)
-
-    def _compare(self, other, method):
-        if not isinstance(other, InstallationCandidate):
-            return NotImplemented
-
-        return method(self._key, other._key)
-
-
 class PackageFinder(object):
     """This finds packages.
 

src/pip/_internal/models/candidate.py

@@ -0,0 +1,47 @@
+from pip._vendor.packaging.version import parse as parse_version
+
+
+class InstallationCandidate(object):
+    """Represents a potential "candidate" for installation.
+    """
+
+
+    def __init__(self, project, version, location):
+        self.project = project
+        self.version = parse_version(version)
+        self.location = location
+        self._key = (self.project, self.version, self.location)
+
+    def __repr__(self):
+        return "<InstallationCandidate({!r}, {!r}, {!r})>".format(
+            self.project, self.version, self.location,
+        )
+
+    # NOTE: pip._internal.index.Link does something similar.
+    #       We could have a "key-based-compare" mixin that these both use.
+    def __hash__(self):
+        return hash(self._key)
+
+    def __lt__(self, other):
+        return self._compare(other, lambda s, o: s < o)
+
+    def __le__(self, other):
+        return self._compare(other, lambda s, o: s <= o)
+
+    def __eq__(self, other):
+        return self._compare(other, lambda s, o: s == o)
+
+    def __ge__(self, other):
+        return self._compare(other, lambda s, o: s >= o)
+
+    def __gt__(self, other):
+        return self._compare(other, lambda s, o: s > o)
+
+    def __ne__(self, other):
+        return self._compare(other, lambda s, o: s != o)
+
+    def _compare(self, other, method):
+        if not isinstance(other, InstallationCandidate):
+            return NotImplemented
+
+        return method(self._key, other._key)

tests/unit/test_models.py

@@ -3,7 +3,7 @@
 
 from pip._vendor.packaging.version import parse as parse_version
 
-from pip._internal.models import index
+from pip._internal.models import index, candidate
 
 
 class TestPackageIndex(object):
@@ -26,3 +26,22 @@ class TestPackageIndex(object):
         assert pack_index.url == "https://pypi.org/"
         assert pack_index.simple_url == "https://pypi.org/simple"
         assert pack_index.pypi_url == "https://pypi.org/pypi"
+
+
+class TestInstallationCandidate(object):
+
+    def test_sets_correct_variables(self):
+        obj = candidate.InstallationCandidate(
+            "A", "1.0.0", "https://somewhere.com/path/A-1.0.0.tar.gz"
+        )
+        assert obj.project == "A"
+        assert obj.version == parse_version("1.0.0")
+        assert obj.location == "https://somewhere.com/path/A-1.0.0.tar.gz"
+
+    # NOTE: This isn't checking the ordering logic; only the data provided to
+    #       it is correct.
+    def test_sets_the_right_key(self):
+        obj = candidate.InstallationCandidate(
+            "A", "1.0.0", "https://somewhere.com/path/A-1.0.0.tar.gz"
+        )
+        assert obj._key == (obj.project, obj.version, obj.location)