Exclude test case in Cargo's target directory

Fixes #59.

lua/neotest-rust/init.lua

@@ -75,6 +75,16 @@ function adapter.is_test_file(file_path)
  return vim.endswith(file_path, ".rs") and #adapter.discover_positions(file_path):to_list() ~= 1
 end
 
+---Filter directories when searching for test files
+---@async
+---@param name string Name of directory
+---@param rel_path string Path to directory, relative to root
+---@param root string Root directory of project
+---@return boolean
+function adapter.filter_dir(name, rel_path, root)
+ return root .. Path.path.sep .. rel_path ~= cargo_metadata(root).target_directory
+end
+
 local get_package_root = lib.files.match_root_pattern("Cargo.toml")
 
 local function is_unit_test(path)

tests/init_spec.lua

@@ -1131,3 +1131,19 @@ describe("results", function()
  assert.are.same(expected, results)
  end)
 end)
+
+describe("filter_dir", function()
+ it("doesn't exclude the src directory", function()
+ local adapter = require("neotest-rust")({})
+ local root = vim.loop.cwd() .. "/tests/data/simple-package"
+
+ assert.equals(adapter.filter_dir("src", "src", root), true)
+ end)
+
+ it("excludes the target directory", function()
+ local adapter = require("neotest-rust")({})
+ local root = vim.loop.cwd() .. "/tests/data/simple-package"
+
+ assert.equals(adapter.filter_dir("target", "target", root), false)
+ end)
+end)