feat: add support for running rspec in a docker container. (#52)

* feat: Add support for running rspec in a docker container.

- Adds `transform_spec_path` config option to allow the spec path to be
  modified before being passed to rspec.
- Adds `results_path` config option to allow the results file to be
  modified (required so that a location which is available to both the
  docker container and host can be used).

* fix: Fix call to async in default results_path function.

README.md

@@ -70,7 +70,13 @@ adapters = {
       })
     end,
     root_files = { "Gemfile", ".rspec", ".gitignore" },
-    filter_dirs = { ".git", "node_modules" }
+    filter_dirs = { ".git", "node_modules" },
+    transform_spec_path = function(path)
+      return path
+    end,
+    results_path = function()
+      return async.fn.tempname()
+    end
   }),
 }
 ```
@@ -131,7 +137,43 @@ require("neotest-rspec")({
 
 ### Running tests in a docker container
 
-Whilst not directly supported by neotest, but you can accomplish this using a shell script as your Rspec command. See [this comment](https://github.com/nvim-neotest/neotest/issues/89#issuecomment-1338141432) for an example.
+The following configuration overrides `rspec_cmd` to run a docker container
+(using docker-compose) and overrides `transform_spec_path` to pass the spec
+file as a relative path instead of an absolute path to rspec. The
+`results_path` needs to be set to a location which is available to both the
+container and the host.
+
+```lua
+require("neotest").setup({
+  adapters = {
+    require("neotest-rspec")({
+      rspec_cmd = function()
+        return vim.tbl_flatten({
+          "docker",
+          "compose",
+          "exec",
+          "-i",
+          "-w", "/app",
+          "-e", "RAILS_ENV=test",
+          "app",
+          "bundle",
+          "exec",
+          "rspec"
+        })
+      end,
+
+      transform_spec_path = function(path)
+        local prefix = require('neotest-rspec').root(path)
+        return string.sub(path, string.len(prefix) + 2, -1)
+      end,
+
+      results_path = "tmp/rspec.output"
+    })
+  }
+})
+```
+
+Alternatively, you can accomplish this using a shell script as your Rspec command. See [this comment](https://github.com/nvim-neotest/neotest/issues/89#issuecomment-1338141432) for an example.
 
 ## :rocket: Usage
 

lua/neotest-rspec/config.lua

@@ -16,4 +16,12 @@ M.get_filter_dirs = function()
   return { ".git", "node_modules" }
 end
 
+M.transform_spec_path = function(path)
+  return path
+end
+
+M.results_path = function()
+  return require("neotest.async").fn.tempname()
+end
+
 return M

lua/neotest-rspec/init.lua

@@ -90,12 +90,13 @@ function NeotestAdapter.build_spec(args)
   local position = args.tree:data()
   local engine_name = nil
 
+  local spec_path = config.transform_spec_path(position.path)
   local path = async.fn.expand("%")
 
   -- if the path starts with spec, it's a normal test. Otherwise, it's an engine test
   local match = vim.regex("^spec/"):match_str(path)
   if match and match ~= 0 then engine_name = string.sub(path, 0, match - 1) end
-  local results_path = async.fn.tempname()
+  local results_path = config.results_path()
 
   local script_args = vim.tbl_flatten({
     "-f",
@@ -107,14 +108,14 @@ function NeotestAdapter.build_spec(args)
   })
 
   local function run_by_filename()
-    table.insert(script_args, position.path)
+    table.insert(script_args, spec_path)
   end
 
   local function run_by_line_number()
     table.insert(
       script_args,
       vim.tbl_flatten({
-        position.path .. ":" .. tonumber(position.range[1] + 1),
+        spec_path .. ":" .. tonumber(position.range[1] + 1),
       })
     )
   end
@@ -199,6 +200,20 @@ setmetatable(NeotestAdapter, {
         return opts.filter_dirs
       end
     end
+    if is_callable(opts.transform_spec_path) then
+      config.transform_spec_path = opts.transform_spec_path
+    elseif opts.transform_spec_path then
+      config.transform_spec_path = function()
+        return opts.transform_spec_path
+      end
+    end
+    if is_callable(opts.results_path) then
+      config.results_path = opts.results_path
+    elseif opts.results_path then
+      config.results_path = function()
+        return opts.results_path
+      end
+    end
     return NeotestAdapter
   end,
 })