[mix][library][test] refactor mix_test to use mix_library compilation artifacts and use a mix_env environment for library compilation

defs.bzl

@@ -11,5 +11,5 @@ def mix_library(*args, **kwargs):
 def mix_release(*args, **kwargs):
     _mix_release(*args, **kwargs)
 
-def mix_test(*args, **kwargs):
-    _mix_test(*args, **kwargs)
+def mix_test(name, lib, **kwargs):
+    _mix_test(name = name, lib = lib, **kwargs)

examples/basic/BUILD.bazel

@@ -3,7 +3,9 @@ load("@rules_elixir//:ex_unit_test.bzl", "ex_unit_test")
 load("@rules_erlang//:escript.bzl", "escript_archive")
 
 load("@rules_elixir//:mix_library.bzl", "mix_library")  # , "mix_release")
+load("@rules_elixir//:mix_test.bzl", "mix_test")
 
+# Production library
 mix_library(
     name = "basic",
     # TODO: we should generate this target, and elicit this name from the mix
@@ -13,6 +15,26 @@ mix_library(
     srcs = glob(['lib/**/*.ex']),
 )
 
+# Test library (compiled with MIX_ENV=test)
+mix_library(
+    name = "basic_test_lib",
+    app_name = "main",
+    mix_env = "test",
+    mix_config = ":mix.exs",
+    srcs = glob(['lib/**/*.ex']),
+)
+
+# Test runner using pre-compiled artifacts
+mix_test(
+    name = "basic_test",
+    lib = ":basic_test_lib",
+    data = glob(['lib/**/*.ex', 'test/**/*.exs']),
+    env = {
+        "ERL_COMPILER_OPTIONS": "deterministic",
+        "ELIXIR_ERL_OPTIONS": "+fnu",
+    },
+)
+
 # TODO: Migrate to elixir_release + elixir_release_bundle
 # The new approach uses:
 #   1. elixir_release to create the release with Elixir-specific processing

examples/basic/test/helped_test.exs

@@ -1,4 +1,4 @@
-defmodule AssertionTest do
+defmodule HelpedTest do
   use ExUnit.Case, async: true
   import TestHelper
 

examples/internal-elixir/BUILD.bazel

@@ -39,32 +39,6 @@ ex_unit_test(
     },
 )
 
-# Example of running mix test on the entire project
-mix_test(
-    name = "mix_test_all",
-    mix_config = "mix.exs",
-    deps = [":erlang_app"],
-    env = {
-        "ERL_COMPILER_OPTIONS": "deterministic",
-        "ELIXIR_ERL_OPTIONS": "+fnu",
-    },
-)
-
-# Example of running mix test on specific test files
-mix_test(
-    name = "mix_test_specific",
-    srcs = [
-        "test/assertion_test.exs",
-    ],
-    mix_config = "mix.exs",
-    deps = [":erlang_app"],
-    env = {
-        "ERL_COMPILER_OPTIONS": "deterministic",
-        "ELIXIR_ERL_OPTIONS": "+fnu",
-    },
-    mix_test_opts = ["--trace"],
-)
-
 platform(
     name = "erlang_internal_platform",
     constraint_values = [

examples/plug-sample/BUILD.bazel

@@ -5,6 +5,7 @@ load("@rules_erlang//:escript.bzl", "escript_archive")
 load("@rules_elixir//:mix_library.bzl", "mix_library")  # , "mix_release")
 load("@rules_elixir//:mix_test.bzl", "mix_test")
 
+# Production library
 mix_library(
     name = "lib",
     # TODO: we should generate this target, and elicit this name from the mix
@@ -17,6 +18,18 @@ mix_library(
     ],
 )
 
+# Test library (compiled with MIX_ENV=test)
+mix_library(
+    name = "lib_test",
+    app_name = "plug_sample",
+    mix_env = "test",
+    mix_config = ":mix.exs",
+    srcs = glob(['lib/**/*.ex']),
+    deps = [
+        "@plug_cryptoasdasd//:plug_crypto"
+    ],
+)
+
 # TODO: Migrate to elixir_release + elixir_release_bundle
 # The new approach uses:
 #   1. elixir_release to create the release with Elixir-specific processing
@@ -43,13 +56,11 @@ mix_library(
 #     command_line_args = ["--no-halt"],
 # )
 
+# Test runner using pre-compiled artifacts
 mix_test(
     name = "plug_sample_test",
-    mix_config = ":mix.exs",
+    lib = ":lib_test",
     data = glob(['lib/**/*.ex', 'test/**/*.exs']),
-    deps = [
-        "@plug_cryptoasdasd//:plug_crypto"
-    ],
     env = {
         "ERL_COMPILER_OPTIONS": "deterministic",
         "ELIXIR_ERL_OPTIONS": "+fnu",

mix_test.bzl

@@ -3,17 +3,18 @@ load(
     _mix_test = "mix_test",
 )
 
-def mix_test(**kwargs):
-    """Run mix test on an Elixir project.
+def mix_test(name, lib, **kwargs):
+    """Run mix test using pre-compiled artifacts from a mix_library.
 
-    This rule runs `mix test` on a Mix project, executing the project's test suite.
+    This rule runs `mix test` on a Mix project using pre-compiled artifacts
+    from a mix_library target. The library must be compiled with mix_env="test".
 
     Args:
         name: The name of the test target
-        mix_config: The mix.exs configuration file (default: ":mix.exs")
+        lib: The mix_library target containing the compiled application.
+             Must be compiled with mix_env="test".
         srcs: Optional list of specific test files to run. If empty, runs all tests in test/
-        data: Additional data files needed for tests
-        deps: Dependencies required for the tests (must provide ErlangAppInfo)
+        data: Additional data files needed for tests (include test/**/*.exs here)
         ez_deps: Erlang/Elixir archive dependencies (.ez files)
         tools: Additional tools needed for tests
         env: Environment variables to set during test execution
@@ -23,15 +24,21 @@ def mix_test(**kwargs):
 
     Example:
         ```python
+        # First, create a test library compiled with MIX_ENV=test
+        mix_library(
+            name = "my_app_test_lib",
+            app_name = "my_app",
+            mix_env = "test",
+            srcs = glob(["lib/**/*.ex"]),
+        )
+
+        # Then create the test target
         mix_test(
-            name = "my_project_test",
-            mix_config = "mix.exs",
-            deps = [":my_app"],
-            env = {
-                "MIX_ENV": "test",
-            },
+            name = "my_app_test",
+            lib = ":my_app_test_lib",
+            data = glob(["test/**/*.exs"]),
             mix_test_opts = ["--trace"],
         )
         ```
     """
-    _mix_test(**kwargs)
+    _mix_test(name = name, lib = lib, **kwargs)

private/mix_info.bzl

@@ -5,6 +5,7 @@ MixProjectInfo = provider(
         # ErlangAppInfo
         # 'app_name': 'Name of the OTP application',
         "mix_config": "Path to the mix.exs file of this Mix project",
+        "mix_env": "The MIX_ENV used to compile this project (prod, test, dev)",
         # 'ebin': 'Directory containing built libs(???)',
         # # TODO: find out how elixir works
         # 'consolidated': 'Directory containing...consolidated...stuff??? how does elixir work?',

private/mix_library.bzl

@@ -70,7 +70,7 @@ def _mix_library_impl(ctx):
     #  - confirm if we need a secondary one of these for non-runtime deps
     #    (or maybe we just construct a combination classpath?)
     erl_libs_path = ""
-    if len(erl_libs_files) > 0:
+    if erl_libs_files:
         erl_libs_path = path_join(
             ctx.bin_dir.path,
             ctx.label.workspace_root,
@@ -93,33 +93,26 @@ def _mix_library_impl(ctx):
     priv_copy_commands = ""
     priv_copy_to_build_dir = ""
     if priv_dir:
-        # Commands to copy priv files to build directory (for Mix to access during compilation)
-        priv_copy_to_build_dir = "\n# Copy priv files to build directory for Mix access\n"
-        for priv_file in ctx.files.priv:
-            rel_path = _priv_file_dest_relative_path(ctx.label, priv_file)
-            priv_copy_to_build_dir += "    mkdir -p \"priv/$(dirname {})\"\n".format(rel_path)
-            # Only copy if source and destination are different (avoid "same file" errors)
-            priv_copy_to_build_dir += "    if [[ \"$ORIG_PWD/{}\" != \"$(pwd)/priv/{}\" ]]; then\n".format(
-                priv_file.path,
-                rel_path
-            )
-            priv_copy_to_build_dir += "        cp -L \"$ORIG_PWD/{}\" \"priv/{}\"\n".format(
-                priv_file.path,
-                rel_path
-            )
-            priv_copy_to_build_dir += "    fi\n"
-
-        # Commands to copy priv files to output directory (for ErlangAppInfo provider)
-        priv_copy_commands = "\n# Copy priv files to output directory preserving directory structure\n"
-        priv_copy_commands += "mkdir -p \"$ABS_OUT_PRIV_DIR\"\n"
+        build_dir_cmds = []
+        output_dir_cmds = []
 
         for priv_file in ctx.files.priv:
             rel_path = _priv_file_dest_relative_path(ctx.label, priv_file)
-            priv_copy_commands += "mkdir -p \"$ABS_OUT_PRIV_DIR/$(dirname {})\"\n".format(rel_path)
-            priv_copy_commands += "cp -L \"$ORIG_PWD/{}\" \"$ABS_OUT_PRIV_DIR/{}\"\n".format(
-                priv_file.path,
-                rel_path
-            )
+            src_path = priv_file.path
+
+            # Commands to copy priv files to build directory (for Mix to access during compilation)
+            build_dir_cmds.append('    mkdir -p "priv/$(dirname {})"'.format(rel_path))
+            # Conditional to avoid same-file errors
+            build_dir_cmds.append('    if [[ "$ORIG_PWD/{}" != "$(pwd)/priv/{}" ]]; then'.format(src_path, rel_path))
+            build_dir_cmds.append('        cp -L "$ORIG_PWD/{}" "priv/{}"'.format(src_path, rel_path))
+            build_dir_cmds.append("    fi")
+
+            # Commands to copy priv files to output directory (for ErlangAppInfo provider)
+            output_dir_cmds.append('mkdir -p "$ABS_OUT_PRIV_DIR/$(dirname {})"'.format(rel_path))
+            output_dir_cmds.append('cp -L "$ORIG_PWD/{}" "$ABS_OUT_PRIV_DIR/{}"'.format(src_path, rel_path))
+
+        priv_copy_to_build_dir = "\n# Copy priv files to build directory for Mix access\n" + "\n".join(build_dir_cmds) + "\n"
+        priv_copy_commands = "\n# Copy priv files to output directory preserving directory structure\nmkdir -p \"$ABS_OUT_PRIV_DIR\"\n" + "\n".join(output_dir_cmds) + "\n"
 
     # TODO: confirm if we need to use include dir from other modules, or if
     # that's just a way for elixir to expose and interface to erlang.
@@ -171,7 +164,7 @@ if [[ -n "$ERL_LIBS_PATH" ]]; then
     done
 fi
 
-MIX_ENV=prod \\
+MIX_ENV={mix_env} \\
     MIX_BUILD_ROOT=_output \\
     MIX_HOME=/tmp \\
     MIX_OFFLINE=true \\
@@ -190,7 +183,7 @@ mkdir -p "$ABS_OUT_DIR"
 
 # NOTE: this directory can contain files other than .app and .beam, but we only
 # want to keep these in our build output.
-cp _output/prod/lib/{app_name}/ebin/*.beam _output/prod/lib/{app_name}/ebin/*.app "$ABS_OUT_DIR/"
+cp _output/{mix_env}/lib/{app_name}/ebin/*.beam _output/{mix_env}/lib/{app_name}/ebin/*.app "$ABS_OUT_DIR/"
 
 # Set priv output directory if priv files exist
 if [[ -n "{priv_out_dir}" ]]; then
@@ -210,6 +203,7 @@ fi
         erl_libs_path = erl_libs_path,
         build_dir = ctx.file.mix_config.dirname,
         name = ctx.label.name,
+        mix_env = ctx.attr.mix_env,
         # env = env,
         # setup = ctx.attr.setup,
         out_dir = ebin.path,
@@ -252,6 +246,7 @@ fi
         MixProjectInfo(
             # app_name = ctx.attr.app_name,
             mix_config = ctx.file.mix_config,
+            mix_env = ctx.attr.mix_env,
             # ebin = '/'.join([ebin.path, 'ebin', 'lib', ctx.attr.app_name, 'ebin']),
             # TODO: should we actually keep this, or should be just YEET the
             # consolidated directory? it seems only have dependencies
@@ -293,6 +288,11 @@ mix_library = rule(
     implementation = _mix_library_impl,
     attrs = {
         "app_name": attr.string(),
+        "mix_env": attr.string(
+            default = "prod",
+            values = ["prod", "test", "dev"],
+            doc = "The MIX_ENV to use when compiling (default: prod)",
+        ),
         "mix_config": attr.label(
             allow_single_file = [".exs"],
             default = ":mix.exs",