Add tests for AvailableDistributions().resolve(). This effectively

completes the core dependency resolution engine; all we need now is a way
to turn sys.path entries into "distribution sources" that can list
Distribution objects for inclusion in an instance of
AvailableDistributions, and the 'require("SomePkg>=2.7")' API will be
usable.

--HG--
branch : setuptools
extra : convert_revision : svn%3A6015fed2-1504-0410-9fe1-9d1591cc4771/sandbox/trunk/setuptools%4041009

pkg_resources.py

@@ -250,12 +250,12 @@ class AvailableDistributions(object):
         if path is None:
             path = sys.path
 
-        requirements = list(requirements)[::1]  # set up the stack
+        requirements = list(requirements)[::-1]  # set up the stack
         processed = {}  # set of processed requirements
         best = {}       # key -> dist
+        to_install = []
 
         while requirements:
-
             req = requirements.pop()
             if req in processed:
                 # Ignore cyclic or redundant dependencies
@@ -268,15 +268,16 @@ class AvailableDistributions(object):
                 dist = best[req.key] = self.best_match(req,path)
                 if dist is None:
                     raise DistributionNotFound(req)  # XXX put more info here
+                to_install.append(dist)
 
-            elif dist not in requirement:
+            elif dist not in req:
                 # Oops, the "best" so far conflicts with a dependency
                 raise VersionConflict(req,dist) # XXX put more info here
 
             requirements.extend(dist.depends(req.options)[::-1])
             processed[req] = True
 
-        return best.values()    # return list of distros to install
+        return to_install    # return list of distros to install
 
 
     def obtain(self, requirement):
@@ -284,7 +285,6 @@ class AvailableDistributions(object):
         return None     # override this in subclasses
 
 
-
 class ResourceManager:
     """Manage resource extraction and packages"""
 
@@ -418,7 +418,6 @@ def require(*requirements):
 
         * get_distro_source() isn't implemented
         * Distribution.install_on() isn't implemented
-        * AvailableDistributions.resolve() is untested
         * AvailableDistributions.scan() is untested
 
     There may be other things missing as well, but this definitely won't work
@@ -448,6 +447,7 @@ def require(*requirements):
 
 
 
+
 
 class DefaultProvider:
     """Provides access to package resources in the filesystem"""

setuptools/tests/test_resources.py

@@ -121,6 +121,47 @@ class DistroTests(TestCase):
             self.checkDepends(self.distDepends(v), v)
 
 
+    def testResolve(self):
+        ad = AvailableDistributions([])
+
+        # Resolving no requirements -> nothing to install
+        self.assertEqual( list(ad.resolve([],[])), [] )
+
+        # Request something not in the collection -> DistributionNotFound
+        self.assertRaises(
+            DistributionNotFound, ad.resolve, parse_requirements("Foo"), []
+        )
+
+        Foo = Distribution.from_filename(
+            "/foo_dir/Foo-1.2.egg",
+            metadata=Metadata(('depends.txt', "[bar]\nBaz>=2.0"))
+        )
+        ad.add(Foo)
+
+        # Request thing(s) that are available -> list to install
+        self.assertEqual(
+            list(ad.resolve(parse_requirements("Foo"),[])), [Foo]
+        )
+
+        # Request an option that causes an unresolved dependency for "Baz"
+        self.assertRaises(
+            DistributionNotFound, ad.resolve,parse_requirements("Foo[bar]"),[]
+        )      
+        Baz = Distribution.from_filename(
+            "/foo_dir/Baz-2.1.egg", metadata=Metadata(('depends.txt', "Foo"))
+        )
+        ad.add(Baz)
+
+        # Install list now includes resolved dependency
+        self.assertEqual(
+            list(ad.resolve(parse_requirements("Foo[bar]"),[])), [Foo,Baz]
+        )
+        # Requests for conflicting versions produce VersionConflict
+        self.assertRaises(
+            VersionConflict,
+            ad.resolve, parse_requirements("Foo==1.2\nFoo!=1.2"), []
+        )
+
     def testDistroDependsOptions(self):
         d = self.distDepends("""
             Twisted>=1.5