diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index 0c12d30..4394d91 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -22,6 +22,11 @@ set_target_properties(
 			uchardet-tests
 )
 
+add_executable(uchardet-lifecycle uchardet-lifecycle.cpp)
+target_link_libraries(uchardet-lifecycle ${UCHARDET_LIBRARY})
+add_test(NAME native-lifecycle COMMAND uchardet-lifecycle)
+set_tests_properties(native-lifecycle PROPERTIES TIMEOUT 10)
+
 # Iterate through all langs.
 file(GLOB dirs "[a-z][a-z]")
 foreach(dir ${dirs})
diff --git a/test/LIFECYCLE.ja.md b/test/LIFECYCLE.ja.md
new file mode 100644
index 0000000..df0e174
--- /dev/null
+++ b/test/LIFECYCLE.ja.md
@@ -0,0 +1,29 @@
+<!-- SPDX-License-Identifier: MIT -->
+# 小規模なnative lifecycle比較
+
+`uchardet-lifecycle`は通常の空入力、ASCII、UTF-8、cp1252の小入力について、
+fresh detectorとreset再利用の同一feed結果を比較するCTest。
+4入力を3巡し、直前の文書とは異なるencodingや空入力へ切り替える。
+
+- finalize後のresetがfreshと同じ初期状態へ戻ること。
+- 途中までfeedした文書をresetで破棄した場合もfreshと一致すること。
+- 同一feed後、および1回のfinalize後のdoneと候補一覧の一致。
+- 候補数・順序・encoding・language（nullと空文字も区別）・confidence bit列を比較。
+- finalize後のgetter再読で出力が変わらないこと。
+
+独自のencoding正解をこのtestへ埋め込まず、同一入力のfresh結果を対照にする。
+自然文corpusのaccuracy試験やchunk間一致試験を置き換えない。
+`uchardet_is_done`は「追加入力が不要」の意味であり、Python wrapperの`closed`と
+同じ状態を表すと仮定しない。
+
+```sh
+cmake -S . -B /disk/lifecycle-build -DBUILD_TESTING=ON -DBUILD_SHARED_LIBS=OFF
+cmake --build /disk/lifecycle-build --target uchardet-lifecycle
+ctest --test-dir /disk/lifecycle-build -R '^native-lifecycle$' --output-on-failure
+```
+
+CTest timeoutは10秒。標準engineや公開APIを変更しない。
+error/OOM注入、arbitrary-byte fuzz、大入力、並列利用、language weightの全契約は未対象。
+nativeの繰返しfinalizeやfinalize後feedについては、Python wrapperが呼出しを抑止する
+挙動とnative C APIの保証を混同せず、今回のtestで保証を追加しない。
+P01を再開したり、#117/#118/#119の全完了を主張したりするものではない。
diff --git a/test/uchardet-lifecycle.cpp b/test/uchardet-lifecycle.cpp
new file mode 100644
index 0000000..88bfcc1
--- /dev/null
+++ b/test/uchardet-lifecycle.cpp
@@ -0,0 +1,106 @@
+// SPDX-License-Identifier: MIT
+// Small valid-input lifecycle checks, not arbitrary-byte or allocation-failure tests.
+#include "uchardet.h"
+#include <cstdint>
+#include <cstring>
+#include <iostream>
+#include <stdexcept>
+#include <string>
+#include <vector>
+
+class Detector {
+ public:
+  Detector() : handle_(uchardet_new()) {
+    if (!handle_) throw std::runtime_error("detector allocation failed");
+  }
+  ~Detector() { uchardet_delete(handle_); }
+  Detector(const Detector&) = delete;
+  Detector& operator=(const Detector&) = delete;
+  uchardet_t get() const { return handle_; }
+ private:
+  uchardet_t handle_;
+};
+
+struct Candidate {
+  std::string encoding, language;
+  bool language_present;
+  std::uint32_t confidence;
+  bool operator==(const Candidate& other) const {
+    return encoding == other.encoding && language == other.language &&
+           language_present == other.language_present && confidence == other.confidence;
+  }
+};
+
+struct Snapshot {
+  bool done;
+  std::vector<Candidate> candidates;
+  bool operator==(const Snapshot& other) const {
+    return done == other.done && candidates == other.candidates;
+  }
+};
+
+static Snapshot snapshot(const Detector& detector) {
+  Snapshot value;
+  value.done = uchardet_is_done(detector.get()) != 0;
+  const size_t count = uchardet_get_n_candidates(detector.get());
+  for (size_t i = 0; i < count; ++i) {
+    Candidate candidate;
+    const char* encoding = uchardet_get_encoding(detector.get(), i);
+    const char* language = uchardet_get_language(detector.get(), i);
+    if (!encoding) throw std::runtime_error("candidate encoding is null");
+    candidate.encoding = encoding;
+    candidate.language_present = language != nullptr;
+    candidate.language = language ? language : "";
+    const float confidence = uchardet_get_confidence(detector.get(), i);
+    static_assert(sizeof(confidence) == sizeof(candidate.confidence), "binary32 required");
+    std::memcpy(&candidate.confidence, &confidence, sizeof(confidence));
+    value.candidates.push_back(candidate);
+  }
+  return value;
+}
+
+static void require_equal(const Snapshot& actual, const Snapshot& expected, const char* stage) {
+  if (!(actual == expected)) throw std::runtime_error(stage);
+}
+
+static void feed(const Detector& detector, const std::string& data) {
+  if (uchardet_handle_data(detector.get(), data.data(), data.size()) != 0)
+    throw std::runtime_error("normal input failed");
+}
+
+int main() {
+  try {
+    const std::vector<std::string> inputs = {
+      "", "plain ASCII text", "caf\xc3\xa9 et th\xc3\xa9", "caf\xe9 et th\xe9"
+    };
+    Detector reused;
+    Detector pristine;
+    const Snapshot initial = snapshot(pristine);
+    unsigned comparisons = 0;
+    for (unsigned cycle = 0; cycle < 3; ++cycle) {
+      for (const std::string& input : inputs) {
+        uchardet_reset(reused.get());
+        require_equal(snapshot(reused), initial, "reset differs from fresh detector");
+        // Reset must discard a previous, unfinished document as well.
+        feed(reused, "old ASCII document");
+        uchardet_reset(reused.get());
+        require_equal(snapshot(reused), initial, "reset after feed differs from fresh detector");
+        Detector fresh;
+        feed(reused, input);
+        feed(fresh, input);
+        require_equal(snapshot(reused), snapshot(fresh), "same-feed state differs after reset");
+        uchardet_data_end(reused.get());
+        uchardet_data_end(fresh.get());
+        const Snapshot expected = snapshot(fresh);
+        require_equal(snapshot(reused), expected, "final candidates differ after reset");
+        require_equal(snapshot(reused), expected, "candidate getters changed finalized output");
+        ++comparisons;
+      }
+    }
+    std::cout << "fresh/reuse lifecycle comparisons: " << comparisons << '\n';
+    return 0;
+  } catch (const std::exception& error) {
+    std::cerr << error.what() << '\n';
+    return 1;
+  }
+}