Add naive and untested version of Lua language support.

tests/repository_test.py

@@ -17,6 +17,7 @@ from pre_commit.envcontext import envcontext
 from pre_commit.hook import Hook
 from pre_commit.languages import golang
 from pre_commit.languages import helpers
+from pre_commit.languages import lua
 from pre_commit.languages import node
 from pre_commit.languages import python
 from pre_commit.languages import ruby
@@ -34,6 +35,7 @@ from testing.util import cwd
 from testing.util import get_resource_path
 from testing.util import skipif_cant_run_coursier
 from testing.util import skipif_cant_run_docker
+from testing.util import skipif_cant_run_lua
 from testing.util import skipif_cant_run_swift
 from testing.util import xfailif_windows
 
@@ -1128,3 +1130,30 @@ def test_non_installable_hook_error_for_additional_dependencies(store, caplog):
         'using language `system` which does not install an environment.  '
         'Perhaps you meant to use a specific language?'
     )
+
+
+@skipif_cant_run_lua  # pragma: win32 no cover
+def test_lua_hook(tempdir_factory, store):
+    _test_hook_repo(
+        tempdir_factory, store, 'lua_repo',
+        'hello-world-lua', [], b'hello world\n',
+    )
+
+
+@skipif_cant_run_lua  # pragma: win32 no cover
+def test_local_lua_additional_dependencies(store):
+    lua_entry = lua._find_lua(C.DEFAULT)
+    config = {
+        'repo': 'local',
+        'hooks': [{
+            'id': 'local-lua',
+            'name': 'local-lua',
+            'entry': lua_entry,
+            'language': 'lua',
+            'args': ['-e', 'require "inspect"; print("hello world")'],
+            'additional_dependencies': ['inspect'],
+        }],
+    }
+    hook = _get_hook(config, store, 'local-lua')
+    ret, out = _hook_run(hook, (), color=False)
+    assert (ret, _norm_out(out)) == (0, b'hello world\n')