build: fix --branch flag

The `--branch` flag is optional and takes a string argument.

The `--branch` flag does not make sense for `luarocks make` because
it does not fetch sources, it builds/installs based on whatever is
in the current directory.

This also adds tests that verify the behavior, but these don't
run in Travis CI because of issues running a Git daemon there.
They were verified locally.

1 files changed, 28 insertions, 1 deletions

diff --git a/spec/install_spec.lua b/spec/install_spec.lua
index 77ac6225..3b0b22fb 100644
--- a/spec/install_spec.lua
+++ b/spec/install_spec.lua
@@ -3,8 +3,8 @@ local lfs = require("lfs")
 local run = test_env.run
 local testing_paths = test_env.testing_paths
 local env_variables = test_env.env_variables
-local get_tmp_path = test_env.get_tmp_path
 local write_file = test_env.write_file
+local git_repo = require("spec.util.git_repo")
 
 test_env.unload_luarocks()
 
@@ -234,4 +234,31 @@ describe("luarocks install #integration", function()
       end)
    end)
 
+   describe("#unix install runs build from #git", function()
+      local git
+
+      setup(function()
+         git = git_repo.start()
+      end)
+      
+      teardown(function()
+         if git then
+            git:stop()
+         end
+      end)
+
+      it("using --branch", function()
+         write_file("my_branch-1.0-1.rockspec", [[
+            rockspec_format = "3.0"
+            package = "my_branch"
+            version = "1.0-1"
+            source = {
+               url = "git://localhost/testrock"
+            }
+         ]], finally)
+         assert.is_false(run.luarocks_bool("install --branch unknown-branch ./my_branch-1.0-1.rockspec"))
+         assert.is_true(run.luarocks_bool("install --branch test-branch ./my_branch-1.0-1.rockspec"))
+      end)
+   end)
+
 end)