Separate test-only Rust sources from Bazel library and binary inputs (#57741)

## What changed

Add `unit_test_srcs` to `codex_rust_crate` to exclude test-only modules from library and binary sources while making them available to unit tests through `compile_data`.

Configure `codex-core` and `codex-tui` to use this option for their test modules and support files.

GitOrigin-RevId: 437b5ddb75e66a96f3c5cb9b309cb0e2608ba169

codex-rs/core/BUILD.bazel

@@ -41,5 +41,17 @@ codex_rust_crate(
         "@platforms//os:macos": 1,
         "//conditions:default": 0,
     }),
+    unit_test_srcs = glob([
+        "src/**/*_test.rs",
+        "src/**/*_tests.rs",
+        "src/**/tests.rs",
+        "src/**/tests/**/*.rs",
+    ]) + [
+        "src/apps/render.rs",
+        "src/config/schema.rs",
+        "src/context/world_state/test_support.rs",
+        "src/guardian/test_host.rs",
+        "src/plugins/test_support.rs",
+    ],
     unit_test_timeout = "long",
 )

codex-rs/tui/BUILD.bazel

@@ -22,4 +22,13 @@ codex_rust_crate(
     },
     # The startup symlink test applies its own Seatbelt policy, which cannot be nested.
     test_tags = ["no-sandbox"],
+    unit_test_srcs = glob([
+        "src/**/*_test_support.rs",
+        "src/**/*_tests.rs",
+        "src/**/*_tests/**/*.rs",
+        "src/**/test_fixtures.rs",
+        "src/**/test_support.rs",
+        "src/**/tests.rs",
+        "src/**/tests/**/*.rs",
+    ]) + ["src/test_backend.rs"],
 )

defs.bzl

@@ -187,6 +187,7 @@ def codex_rust_crate(
         crate_name,
         crate_features = [],
         crate_srcs = None,
+        unit_test_srcs = [],
         crate_edition = None,
         proc_macro = False,
         build_script_enabled = True,
@@ -232,6 +233,8 @@ def codex_rust_crate(
             optional functionality to a separate crate.
         crate_srcs: Optional explicit library srcs; [] disables the library target.
             Defaults to `src/**/*.rs` excluding binary entrypoints.
+        unit_test_srcs: Rust modules loaded only under cfg(test). Excluded from
+            library and binary sources, but available when compiling unit tests.
         crate_edition: Rust edition override, if not default.
             You probably don't want this, it's only here for a single caller.
         proc_macro: Whether this crate builds a proc-macro library.
@@ -315,6 +318,7 @@ def codex_rust_crate(
     binaries = package_data["binaries"]
 
     lib_srcs = crate_srcs if crate_srcs != None else native.glob(["src/**/*.rs"], exclude = binaries.values(), allow_empty = True)
+    lib_srcs = [src for src in lib_srcs if src not in unit_test_srcs]
 
     maybe_deps = []
 
@@ -359,6 +363,7 @@ def codex_rust_crate(
             name = unit_test_binary,
             crate = name,
             crate_features = crate_features,
+            compile_data = unit_test_srcs,
             deps = all_crate_deps(normal = True, normal_dev = True) + maybe_deps + deps_extra,
             # Unit tests also compile to standalone Windows executables, so
             # keep their stack reserve aligned with binaries and integration
@@ -434,7 +439,7 @@ def codex_rust_crate(
             # Isolate status inputs in build-commit-env's cheap action so its
             # output, and hence this compiler input, changes only with the commit.
             rustc_env_files = ["//bazel/build-info:build-commit-env"] if binary in binaries_with_build_commit else [],
-            srcs = native.glob(["src/**/*.rs"], exclude = [main], allow_empty = True) + [main],
+            srcs = native.glob(["src/**/*.rs"], exclude = [main] + unit_test_srcs, allow_empty = True) + [main],
             testonly = binary in test_only_binaries,
             stamp = 0,
             version = crate_version,
@@ -451,6 +456,7 @@ def codex_rust_crate(
             name = binary_unit_test_binary,
             crate = ":" + binary,
             crate_features = crate_features,
+            compile_data = unit_test_srcs,
             deps = all_crate_deps(normal_dev = True),
             rustc_flags = rustc_flags_extra + WINDOWS_RUSTC_LINK_FLAGS + [
                 "--remap-path-prefix=../codex-rs=",