feat(pytest): populate parameterized test instances (#36)

Co-authored-by: Rónán Carrigan <rcarriga@tcd.ie>

README.md

@@ -38,7 +38,9 @@ require("neotest").setup({
         is_test_file = function(file_path)
           ...
         end,
-        
+        -- !!EXPERIMENTAL!! Enable shelling out to `pytest` to discover test
+        -- instances for files containing a parametrize mark (default: false)
+        pytest_discover_instances = true,
     })
   }
 })

lua/neotest-python/init.lua

@@ -1,6 +1,7 @@
 local async = require("neotest.async")
 local lib = require("neotest.lib")
 local base = require("neotest-python.base")
+local pytest = require("neotest-python.pytest")
 
 local function get_script()
   local paths = vim.api.nvim_get_runtime_file("neotest.py", true)
@@ -15,6 +16,7 @@ end
 
 local dap_args
 local is_test_file = base.is_test_file
+local pytest_discover_instances = false
 
 local function get_strategy_config(strategy, python, program, args)
   local config = {
@@ -80,8 +82,13 @@ function PythonNeotestAdapter.filter_dir(name)
 end
 
 ---@async
----@return Tree | nil
+---@return neotest.Tree | nil
 function PythonNeotestAdapter.discover_positions(path)
+  local root = PythonNeotestAdapter.root(path) or vim.loop.cwd()
+  local python = get_python(root)
+  local runner = get_runner(python)
+
+  -- Parse the file while pytest is running
   local query = [[
     ;; Match undecorated functions
     ((function_definition
@@ -109,12 +116,15 @@ function PythonNeotestAdapter.discover_positions(path)
      (#not-has-parent? @namespace.definition decorated_definition)
     )
   ]]
-  local root = PythonNeotestAdapter.root(path)
+  local positions = lib.treesitter.parse_positions(path, query, {
-  local python = get_python(root)
-  local runner = get_runner(python)
-  return lib.treesitter.parse_positions(path, query, {
     require_namespaces = runner == "unittest",
   })
+
+  if runner == "pytest" and pytest_discover_instances then
+    pytest.augment_positions(python, get_script(), path, positions, root)
+  end
+
+  return positions
 end
 
 ---@async
@@ -232,6 +242,9 @@ setmetatable(PythonNeotestAdapter, {
     if type(opts.dap) == "table" then
       dap_args = opts.dap
     end
+    if opts.pytest_discover_instances ~= nil then
+      pytest_discover_instances = opts.pytest_discover_instances
+    end
     return PythonNeotestAdapter
   end,
 })

lua/neotest-python/pytest.lua

@@ -0,0 +1,101 @@
+local lib = require("neotest.lib")
+local logger = require("neotest.logging")
+
+local M = {}
+
+---@async
+---Add test instances for path in root to positions
+---@param positions neotest.Tree
+---@param test_params table<string, string[]>
+local function add_test_instances(positions, test_params)
+  for _, node in positions:iter_nodes() do
+    local position = node:data()
+    if position.type == "test" then
+      local pos_params = test_params[position.id] or {}
+      for _, params_str in ipairs(pos_params) do
+        local new_data = vim.tbl_extend("force", position, {
+          id = string.format("%s[%s]", position.id, params_str),
+          name = string.format("%s[%s]", position.name, params_str),
+        })
+        new_data.range = nil
+
+        local new_pos = node:new(new_data, {}, node._key, {}, {})
+        node:add_child(new_data.id, new_pos)
+      end
+    end
+  end
+end
+
+---@async
+---@param path string
+---@return boolean
+local function has_parametrize(path)
+  local query = [[
+    ;; Detect parametrize decorators
+    (decorator
+      (call
+        function:
+          (attribute
+            attribute: (identifier) @parametrize
+            (#eq? @parametrize "parametrize"))))
+  ]]
+  local content = lib.files.read(path)
+  local ts_root, lang = lib.treesitter.get_parse_root(path, content, { fast = true })
+  local built_query = lib.treesitter.normalise_query(lang, query)
+  return built_query:iter_matches(ts_root, content)() ~= nil
+end
+
+---@async
+---Discover test instances for path (by running script using python)
+---@param python string[]
+---@param script string
+---@param path string
+---@param positions neotest.Tree
+---@param root string
+local function discover_params(python, script, path, positions, root)
+  local cmd = vim.tbl_flatten({ python, script, "--pytest-collect", path })
+  logger.debug("Running test instance discovery:", cmd)
+
+  local test_params = {}
+  local res, data = lib.process.run(cmd, { stdout = true, stderr = true })
+  if res ~= 0 then
+    logger.warn("Pytest discovery failed")
+    if data.stderr then
+      logger.debug(data.stderr)
+    end
+    return {}
+  end
+
+  for line in vim.gsplit(data.stdout, "\n", true) do
+    local param_index = string.find(line, "[", nil, true)
+    if param_index then
+      local test_id = root .. lib.files.path.sep .. string.sub(line, 1, param_index - 1)
+      local param_id = string.sub(line, param_index + 1, #line - 1)
+
+      if positions:get_key(test_id) then
+        if not test_params[test_id] then
+          test_params[test_id] = { param_id }
+        else
+          table.insert(test_params[test_id], param_id)
+        end
+      end
+    end
+  end
+  return test_params
+end
+
+---@async
+---Launch pytest to discover test instances for path, if configured
+---@param python string[]
+---@param script string
+---@param path string
+---@param positions neotest.Tree
+---@param root string
+function M.augment_positions(python, script, path, positions, root)
+  if has_parametrize(path) then
+    local test_params = discover_params(python, script, path, positions, root)
+    add_test_instances(positions, test_params)
+  end
+end
+
+return M

neotest_python/__init__.py

@@ -41,6 +41,12 @@ parser.add_argument("args", nargs="*")
 
 
 def main(argv: List[str]):
+    if "--pytest-collect" in argv:
+        argv.remove("--pytest-collect")
+        from .pytest import collect
+        collect(argv)
+        return
+
     args = parser.parse_args(argv)
     adapter = get_adapter(TestRunner(args.runner))
 

neotest_python/pytest.py

@@ -106,6 +106,7 @@ class NeotestResultCollector:
         if getattr(item, "callspec", None) is not None:
             # Parametrized test
             msg_prefix = f"[{item.callspec.id}] "
+            pos_id += f"[{item.callspec.id}]"
         if report.outcome == "failed":
             exc_repr = report.longrepr
             # Test fails due to condition outside of test e.g. xfail
@@ -176,3 +177,7 @@ class NeotestDebugpyPlugin:
             py_db.stop_on_unhandled_exception(py_db, thread, additional_info, excinfo)
         finally:
             additional_info.is_tracing -= 1
+
+
+def collect(args):
+    pytest.main(['--collect-only', '-q'] + args)