Use a hermetic python and install lit

BUILD

@@ -0,0 +1,5 @@
+# An MLIR tutorial
+
+package(
+    default_visibility = ["//visibility:public"],
+)

WORKSPACE

@@ -1,5 +1,6 @@
 workspace(name = "mlir_tutorial")
 
+load("@bazel_tools//tools/build_defs/repo:git.bzl", "new_git_repository")
 load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
 load("@bazel_tools//tools/build_defs/repo:utils.bzl", "maybe")
 
@@ -68,9 +69,40 @@ maybe(
 # https://github.com/hedronvision/bazel-compile-commands-extractor
 http_archive(
     name = "hedron_compile_commands",
-    url = "https://github.com/hedronvision/bazel-compile-commands-extractor/archive/3dddf205a1f5cde20faf2444c1757abe0564ff4c.tar.gz",
-    strip_prefix = "bazel-compile-commands-extractor-3dddf205a1f5cde20faf2444c1757abe0564ff4c",
     sha256 = "3cd0e49f0f4a6d406c1d74b53b7616f5e24f5fd319eafc1bf8eee6e14124d115",
+    strip_prefix = "bazel-compile-commands-extractor-3dddf205a1f5cde20faf2444c1757abe0564ff4c",
+    url = "https://github.com/hedronvision/bazel-compile-commands-extractor/archive/3dddf205a1f5cde20faf2444c1757abe0564ff4c.tar.gz",
 )
+
 load("@hedron_compile_commands//:workspace_setup.bzl", "hedron_compile_commands_setup")
+
 hedron_compile_commands_setup()
+
+# Depend on a hermetic python version
+new_git_repository(
+    name = "rules_python",
+    commit = "9ffb1ecd9b4e46d2a0bca838ac80d7128a352f9f",  # v0.23.1
+    remote = "https://github.com/bazelbuild/rules_python.git",
+)
+
+load("@rules_python//python:repositories.bzl", "python_register_toolchains")
+
+python_register_toolchains(
+    name = "python3_10",
+    # Available versions are listed at
+    # https://github.com/bazelbuild/rules_python/blob/main/python/versions.bzl
+    python_version = "3.10",
+)
+
+load("@python3_10//:defs.bzl", "interpreter")
+load("@rules_python//python:pip.bzl", "pip_parse")
+
+pip_parse(
+    name = "mlir_tutorial_pip_deps",
+    python_interpreter_target = interpreter,
+    requirements_lock = "//:requirements.txt",
+)
+
+load("@mlir_tutorial_pip_deps//:requirements.bzl", "install_deps")
+
+install_deps()

bazel/lit.bzl

@@ -1,6 +1,7 @@
 """Macros for defining lit tests."""
 
 load("@bazel_skylib//lib:paths.bzl", "paths")
+load("@rules_python//python:py_test.bzl", "py_test")
 
 _DEFAULT_FILE_EXTS = ["mlir"]
 
@@ -44,7 +45,7 @@ def lit_test(name = None, src = None, size = "small", tags = None):
         srcs = [src],
     )
 
-    native.py_test(
+    py_test(
         name = name,
         size = size,
         # -v ensures lit outputs useful info during test failures

requirements.txt

@@ -0,0 +1 @@
+lit==16.0.6

tests/BUILD

@@ -12,6 +12,7 @@ filegroup(
         "@llvm-project//llvm:not",
         "@llvm-project//mlir:mlir-cpu-runner",
         "@llvm-project//mlir:mlir-opt",
+        "@mlir_tutorial_pip_deps_lit//:pkg",
     ],
 )