Add support for namespaces.

For details of the new feature, see
https://github.com/luarocks/luarocks/wiki/Namespaces

This ended up being a huge commit because of some major refactoring
motivated by the new feature:

* new modules for some object types:
  * `luarocks.queries` - all functions that look for rocks in local or
    remote repositories now use objects constructed by this module:
    query objects contain the name, namespace and query constraints.
    Dependencies in a rockspec are also stored as query objects.
  * `luarocks.results` - all individual results produces from queries
    are returned in this format: result objects contain the name,
    namespace, version, arch and repo.
* the `results` object was renamed to `result_tree`, to better
  reflect that it is not an array of `result` objects.
* `luarocks.vers` was removed, its functionality was moved to better locations.

Specifically on namespaces:

* Commands that take a rock `name` can now take `namespace/name`
  (and alternately `--flags=namespace` so that URLs can be
  also installed with a nominal namespace).
* Rocks installed from a namespace now create a `rock_namespace`
  file alongside `rock_manifest`, which is used when matching
  namespaced dependencies against locally-installed rocks.
* Using namespaced dependencies in a rockspec, requires
  `rockspec_format = "3.0"`.
* Tests under the `#namespaces` hashtag, all using a local repository.

1 files changed, 21 insertions, 0 deletions

diff --git a/spec/download_spec.lua b/spec/download_spec.lua
index 64443922..152470a5 100644
--- a/spec/download_spec.lua
+++ b/spec/download_spec.lua
@@ -1,6 +1,7 @@
 local test_env = require("spec.util.test_env")
 local lfs = require("lfs")
 local run = test_env.run
+local testing_paths = test_env.testing_paths
 
 test_env.unload_luarocks()
 
@@ -33,4 +34,24 @@ describe("LuaRocks download tests #blackbox #b_download", function()
       assert.is.truthy(lfs.attributes("validate-args-1.5.4-1.rockspec"))
       test_env.remove_files(lfs.currentdir(), "validate--args--")
    end)
+
+   describe("#namespaces", function()
+      it("retrieves namespaced rockspec", function()
+         finally(function()
+            os.remove("a_rock-2.0-1.rockspec")
+         end)
+         assert(run.luarocks_bool("download a_user/a_rock --rockspec --server=" .. testing_paths.fixtures_dir .. "/a_repo" ))
+         assert(lfs.attributes("a_rock-2.0-1.rockspec"))
+      end)
+
+      it("retrieves namespaced rock", function()
+         finally(function()
+            os.remove("a_rock-2.0-1.src.rock")
+         end)
+         assert(run.luarocks_bool("download a_user/a_rock --server=" .. testing_paths.fixtures_dir .. "/a_repo" ))
+         assert(lfs.attributes("a_rock-2.0-1.src.rock"))
+      end)
+   end)
+
+
 end)