gn analyze output:
{
  "compile_targets": [],
  "status": "No dependency",
  "test_targets": []
}
gn analyze input:
{
  "files": [
    "//libcxx/include/__config",
    "//libcxx/test/std/depr/depr.c.headers/uchar_h.compile.pass.cpp",
    "//libcxx/test/std/depr/depr.c.headers/uchar_h_char8_t.compile.pass.cpp",
    "//libcxx/test/std/strings/c.strings/cuchar.compile.pass.cpp",
    "//libcxx/test/std/strings/c.strings/cuchar_char8_t.compile.pass.cpp",
    "//libcxx/test/std/strings/c.strings/no_c8rtomb_mbrtoc8.verify.cpp",
    "//libcxx/utils/libcxx/test/features.py"
  ],
  "test_targets": [
    "//clang-tools-extra/clangd/test:check-clangd",
    "//clang-tools-extra/test:check-clang-tools",
    "//clang/test:check-clang",
    "//compiler-rt/test/hwasan:check-hwasan",
    "//lld/test:check-lld",
    "//llvm/test:check-llvm"
  ],
  "additional_compile_targets": []
}