test_resources.py 文件源码

def testResolve(self):
        ad = pkg_resources.Environment([])
        ws = WorkingSet([])
        # Resolving no requirements -> nothing to install
        assert list(ws.resolve([], ad)) == []
        # Request something not in the collection -> DistributionNotFound
        with pytest.raises(pkg_resources.DistributionNotFound):
            ws.resolve(parse_requirements("Foo"), ad)

        Foo = Distribution.from_filename(
            "/foo_dir/Foo-1.2.egg",
            metadata=Metadata(('depends.txt', "[bar]\nBaz>=2.0"))
        )
        ad.add(Foo)
        ad.add(Distribution.from_filename("Foo-0.9.egg"))

        # Request thing(s) that are available -> list to activate
        for i in range(3):
            targets = list(ws.resolve(parse_requirements("Foo"), ad))
            assert targets == [Foo]
            list(map(ws.add,targets))
        with pytest.raises(VersionConflict):
            ws.resolve(parse_requirements("Foo==0.9"), ad)
        ws = WorkingSet([]) # reset

        # Request an extra that causes an unresolved dependency for "Baz"
        with pytest.raises(pkg_resources.DistributionNotFound):
            ws.resolve(parse_requirements("Foo[bar]"), ad)
        Baz = Distribution.from_filename(
            "/foo_dir/Baz-2.1.egg", metadata=Metadata(('depends.txt', "Foo"))
        )
        ad.add(Baz)

        # Activation list now includes resolved dependency
        assert list(ws.resolve(parse_requirements("Foo[bar]"), ad)) ==[Foo,Baz]
        # Requests for conflicting versions produce VersionConflict
        with pytest.raises(VersionConflict) as vc:
            ws.resolve(parse_requirements("Foo==1.2\nFoo!=1.2"), ad)

        msg = 'Foo 0.9 is installed but Foo==1.2 is required'
        assert vc.value.report() == msg