feat: 實作 bear CLI 骨架與 PAT 模式共用基礎（issue #6）

- 專案骨架：Elixir + Mix escript（單檔可執行 bear），HTTP 一律 Req
- 設定／憑證檔讀寫：0600、原子寫入（rename）、O_CREAT|O_EXCL 防 symlink
- PAT Bearer 呼叫 /userinfo；--json 輸出；規格化退出碼
- 補齊 main 規格承諾的 BEAR_TOKEN 環境變數（優先於憑證檔、不寫入）
- login 無效 PAT 退出碼 3（依 docs/commands.md §3.1）；token --refresh 用法錯誤 2（§3.3）
- 35 個單元測試；mix precommit（compile --warnings-as-errors + format + test）全綠
- 沿用已關閉 PR #3 的實作（feat/pat-mode-mvp 分支），文件改依 main 現行版本更新

apps 管理指令待 #5 規格與 alterminal/bear#28 API 就緒後實作。

.formatter.exs

@@ -0,0 +1,3 @@
+[
+  inputs: ["{mix,.formatter}.exs", "{config,lib,test}/**/*.{ex,exs}"]
+]

.gitignore

@@ -8,6 +8,7 @@ erl_crash.dump
 *.ez
 bear-*.tar
 bear_cli-*.tar
+/bear
 /tmp/
 
 # 憑證與本機狀態（嚴禁進入版本庫）

README.md

@@ -2,7 +2,7 @@
 
 **Bear CLI** 是 [澳特科技](https://alterminal.com)（Alter Technology）單點登入系統 [Bear](https://gitea.alterminal.com/alterminal/bear) 的**終端機（CLI）客戶端**：讓使用者在 Linux 終端機以 Bear 帳號登入（Device Flow 或個人存取權杖）、查詢身分、取得 Token，作為 SSO 的終端入口。
 
-> **狀態：規劃階段**。本倉庫目前只規劃指令介面（command spec），**尚未實作任何程式碼**。
+> **狀態：已實作 PAT 模式 MVP（Elixir + Req，issue #6）**。`login --token <PAT>`、`whoami`、`token`、`logout`、`status` 已可用；Device Authorization Grant（RFC 8628）登入待伺服器端 P1（bear 倉庫）完成後再接。
 > 伺服器端採用的 OIDC **Device Authorization Grant（RFC 8628）** 方向，詳見 bear 倉庫的設計文件 `docs/cli-feature-plan.md`（issue #17）。
 > Bear 已支援**個人存取權杖（Personal Access Token，PAT）**；CLI 規劃以其作為完全免瀏覽器的替代登入方式（見下文）。
 
@@ -29,6 +29,33 @@ Bear 目前所有流程都依賴「瀏覽器」：登入 `/login`、儀表板 La
 
 ---
 
+## 實作狀態（PAT 模式 MVP）
+
+目前已實作**個人存取權杖（PAT）模式**的最小可用版本（issue #6 骨架部分）：
+
+| 指令 | 狀態 |
+|------|------|
+| `bear login --token <PAT>` | ✅ 已實作（PAT 模式；Device Flow 待伺服器端 P1） |
+| `bear whoami` | ✅ 已實作（`GET /userinfo`，Bearer PAT；支援 `BEAR_TOKEN` 環境變數） |
+| `bear token` | ✅ 已實作（印出 PAT；`--refresh` 為用法錯誤） |
+| `bear logout` | ✅ 已實作（清除本機憑證；PAT 需至網頁撤銷） |
+| `bear status` | ✅ 已實作（純本機判定，顯示 PAT／環境變數模式） |
+| `bear apps` | ⏳ 待 #5 規格與 alterminal/bear#28 API 就緒後實作 |
+
+### 建置與執行
+
+```bash
+mix deps.get          # 安裝依賴（Req、Jason）
+mix test              # 跑單元測試
+mix escript.build     # 產生單檔可執行 `bear`
+./bear --help
+./bear login --token <PAT> --issuer https://alterminal.com
+```
+
+> 發行格式目前採 `mix escript`（目標機需 Erlang）；self-contained release（bakeware/burrito）仍為待定方向（見 `docs/commands.md` §7）。
+
+---
+
 ## 全域選項
 
 | 選項 | 說明 | 預設 |

docs/commands.md

@@ -1,7 +1,7 @@
 # Bear CLI 指令規劃（Command Spec）
 
-> 狀態：規劃草案（對應 issue #19「創建 bear cli 倉庫」）
+> 狀態：P2 PAT 模式 MVP 已實作（見第 9 節）；Device Flow 待伺服器端 P1。
-> 範圍：**本文件只規劃指令介面，不實作程式碼**。
+> 範圍：本文件為指令介面規格；App 管理指令（`bear apps` CRUD）另見 #5 規劃。
 > 登入採用的 OIDC Device Authorization Grant（RFC 8628）細節，見 bear 倉庫 `docs/cli-feature-plan.md`（issue #17）。
 > 另支援以**個人存取權杖（PAT）**登入（bear 已於 profile 頁提供 PAT 建立／列表／撤銷，`/userinfo` 接受 PAT 作為 Bearer）。
 
@@ -255,3 +255,32 @@ bear apps
 | `token --refresh` | `POST /token`（refresh_token，僅 Device Flow） |
 | `logout` | `POST /revoke`（僅 Device Flow；PAT 僅本機刪除，撤銷走網頁 `/profile/tokens`） |
 | `apps`（P3） | 待新增「公開應用清單」API |
+
+---
+
+## 9. 現行實作狀態（PAT 模式 MVP，issue #6）
+
+目前實作為 **PAT 模式 MVP**（Elixir + Req、mix escript），與上方 Device Flow 規格的差異：
+
+| 指令 | 原規格（Device Flow） | 現行實作（PAT 模式） |
+|------|----------------------|----------------------|
+| `login` | 裝置碼流程 | `--token <PAT>` 驗證 `GET /userinfo` 後保存（`-` 可從 stdin 讀）；未給 `--token` 時提示 Device Flow 尚未開放（退出碼 2） |
+| `whoami` | `GET /userinfo`（refresh 輪轉） | `GET /userinfo`（Bearer PAT，無輪轉）；`BEAR_TOKEN` 提供時優先使用 |
+| `token` | refresh token 輪轉換新 | 直接印出 PAT；`--refresh` 為用法錯誤（退出碼 2）；`BEAR_TOKEN` 提供時優先印出 |
+| `logout` | `POST /revoke`（撤銷 refresh token） | 僅清除本機憑證；PAT 需至網頁 `/profile/tokens` 撤銷 |
+| `status` | 顯示 access token 剩餘秒數 | 純本機判定：顯示模式（PAT／BEAR_TOKEN 環境變數）與 issuer |
+| `apps` | P3 暫緩 | 未實作；App 管理指令規格見 #5，伺服器端 API 見 alterminal/bear#28 |
+
+退出碼差異：`login`／`whoami` 的 token 無效（401）依 §3.1 為 `3`（本節實作一致）。
+
+憑證檔結構（PAT 模式，0600、原子寫入、O_EXCL）：
+
+```json
+{"issuer": "https://alterminal.com", "access_token": "<PAT>", "email": "..."}
+```
+
+建置：
+
+```bash
+mix deps.get && mix test && mix escript.build   # 產生單檔可執行 bear
+```

lib/bear_cli.ex

@@ -0,0 +1,14 @@
+defmodule BearCli do
+  @moduledoc """
+  Bear CLI — Bear SSO 的終端機客戶端。
+
+  以 Bear 個人存取權杖（Personal Access Token, PAT）在終端機登入，查詢身分
+  （`whoami`）、取得 Token（`token`），作為 SSO 的終端入口。Device
+  Authorization Grant（RFC 8628）登入待伺服器端 P1（bear 倉庫）完成後再接上。
+  """
+
+  @version "0.1.0"
+
+  @doc "回傳 CLI 版本字串（與 mix.exs 的 version 同步）。"
+  def version, do: @version
+end

lib/bear_cli/api.ex

@@ -0,0 +1,54 @@
+defmodule BearCli.Api do
+  @moduledoc """
+  Bear 伺服器 HTTP 介面（一律使用 `Req`）。
+
+  目前僅實作 PAT 模式所需的 `GET /userinfo`。
+  """
+
+  @finch BearCli.Finch
+
+  @doc """
+  呼叫 `GET {issuer}/userinfo`（Bearer token）。
+
+  回傳：
+    - `{:ok, claims}` — 200，claims 為 JSON map
+    - `{:error, :unauthorized, description}` — 401
+    - `{:error, :server_error, status}` — 其他非 2xx
+    - `{:error, :network, reason}` — 傳輸層錯誤
+  """
+  def userinfo(issuer, token) do
+    url = String.trim_trailing(issuer, "/") <> "/userinfo"
+
+    case Req.get(url,
+           headers: [authorization: "Bearer " <> token, accept: "application/json"],
+           retry: false,
+           finch: [name: @finch]
+         ) do
+      {:ok, %Req.Response{status: 200, body: body}} ->
+        {:ok, decode_body(body)}
+
+      {:ok, %Req.Response{status: 401, body: body}} ->
+        {:error, :unauthorized, error_description(body)}
+
+      {:ok, %Req.Response{status: status}} ->
+        {:error, :server_error, status}
+
+      {:error, exception} ->
+        {:error, :network, Exception.message(exception)}
+    end
+  end
+
+  defp decode_body(%{} = body), do: body
+  defp decode_body(body) when is_binary(body), do: Jason.decode!(body)
+  defp decode_body(_), do: %{}
+
+  defp error_description(body) when is_binary(body) do
+    case Jason.decode(body) do
+      {:ok, %{"error_description" => desc}} when is_binary(desc) -> desc
+      {:ok, %{"error" => err}} when is_binary(err) -> err
+      _ -> "invalid_token"
+    end
+  end
+
+  defp error_description(_), do: "invalid_token"
+end

lib/bear_cli/cli.ex

@@ -0,0 +1,480 @@
+defmodule BearCli.CLI do
+  @moduledoc """
+  `bear` 指令的命令列入口與指令分派。
+
+  指令：`login`（PAT 模式）、`whoami`、`token`、`logout`、`status`。
+
+  `BEAR_TOKEN` 環境變數（一次性／CI 用的 PAT）提供時，`whoami`／`token`／`status`
+  優先使用該值，不讀寫本機憑證檔。
+  """
+
+  alias BearCli.{Api, Config, Credentials}
+
+  @global_switches [
+    issuer: :string,
+    config: :string,
+    json: :boolean,
+    verbose: :boolean,
+    help: :boolean,
+    version: :boolean
+  ]
+  @global_aliases [v: :verbose, h: :help]
+
+  @login_switches [token: :string, scope: :string, "client-id": :string]
+  @token_switches [refresh: :boolean]
+
+  # -- escript 入口 --
+
+  @doc "escript 主函式。執行後以 `System.halt/1` 設定退出碼。"
+  def main(argv) do
+    start_apps()
+    code = argv |> parse() |> dispatch()
+    System.halt(code)
+  end
+
+  # Req 預設用 Finch 作為 HTTP adapter，escript 需自行啟動一個 pool。
+  defp start_apps do
+    _ = Application.ensure_all_started(:req)
+    _ = Application.ensure_all_started(:finch)
+
+    case Finch.start_link(name: BearCli.Finch) do
+      {:ok, _} -> :ok
+      {:error, _} -> :ok
+    end
+
+    :ok
+  end
+
+  # -- 解析 --
+
+  @doc """
+  解析 argv，回傳：
+
+    - `{:version, opts}`
+    - `{:help, opts}`
+    - `{:ok, command, opts}`（opts 為 atom key 的 map）
+    - `{:error, message, exit_code}`
+  """
+  def parse(argv) do
+    argv = Enum.map(argv, &to_string/1)
+
+    case OptionParser.parse_head(argv, strict: @global_switches, aliases: @global_aliases) do
+      {global, rest, []} ->
+        do_parse(global, rest)
+
+      {_global, _rest, [{opt, _} | _]} ->
+        {:error, "未知選項：#{opt}", 2}
+    end
+  end
+
+  defp do_parse(global, rest) do
+    cond do
+      global[:version] ->
+        {:version, %{}}
+
+      global[:help] == true and rest == [] ->
+        {:help, %{}}
+
+      rest == [] ->
+        {:help, %{}}
+
+      true ->
+        [command | args] = rest
+        parse_command(command, args, global)
+    end
+  end
+
+  defp parse_command("login", args, global) do
+    with {:ok, opts} <- parse_opts(args, @global_switches ++ @login_switches) do
+      {:ok, :login, merge_opts(global, opts)}
+    end
+  end
+
+  defp parse_command("whoami", args, global) do
+    with {:ok, opts} <- parse_opts(args, @global_switches) do
+      {:ok, :whoami, merge_opts(global, opts)}
+    end
+  end
+
+  defp parse_command("token", args, global) do
+    with {:ok, opts} <- parse_opts(args, @global_switches ++ @token_switches) do
+      {:ok, :token, merge_opts(global, opts)}
+    end
+  end
+
+  defp parse_command("logout", args, global) do
+    with {:ok, opts} <- parse_opts(args, @global_switches) do
+      {:ok, :logout, merge_opts(global, opts)}
+    end
+  end
+
+  defp parse_command("status", args, global) do
+    with {:ok, opts} <- parse_opts(args, @global_switches) do
+      {:ok, :status, merge_opts(global, opts)}
+    end
+  end
+
+  defp parse_command(unknown, _args, _global) do
+    {:error, "未知指令：#{unknown}（可用 bear --help 查看說明）", 2}
+  end
+
+  defp parse_opts(args, switches) do
+    case OptionParser.parse(args, strict: switches) do
+      {opts, [], []} ->
+        {:ok, opts}
+
+      {_opts, extra, []} ->
+        {:error, "不接受的參數：#{Enum.join(extra, " ")}", 2}
+
+      {_opts, _extra, [{opt, _} | _]} ->
+        {:error, "無法解析選項：#{opt}", 2}
+    end
+  end
+
+  defp merge_opts(global, opts) do
+    Map.merge(Map.new(global), Map.new(opts))
+  end
+
+  # -- 分派 --
+
+  @doc """
+  執行已解析的指令，回傳退出碼。`opts[:api]` 可注入假的 userinfo 函式供測試。
+  """
+  def dispatch(parsed, opts \\ []) do
+    api = opts[:api] || (&Api.userinfo/2)
+
+    case parsed do
+      {:version, _} ->
+        IO.puts(BearCli.version())
+        0
+
+      {:help, _} ->
+        print_help()
+        0
+
+      {:error, message, code} ->
+        IO.puts(:stderr, "錯誤：#{message}")
+        code
+
+      {:ok, command, cmd_opts} ->
+        cond do
+          cmd_opts[:version] ->
+            IO.puts(BearCli.version())
+            0
+
+          cmd_opts[:help] ->
+            print_help()
+            0
+
+          true ->
+            run(command, cmd_opts, api)
+        end
+    end
+  end
+
+  # -- 指令實作 --
+
+  defp run(:login, opts, api) do
+    case opts[:token] do
+      nil ->
+        IO.puts(:stderr, "Device Flow 登入尚未開放（伺服器端 P1 未實作）。")
+        IO.puts(:stderr, "請改用個人存取權杖登入：bear login --token <PAT>")
+        2
+
+      "" ->
+        fail(opts, "token 不可為空", 2)
+
+      token ->
+        token = if token == "-", do: read_token_from_stdin(), else: token
+        do_login(opts, token, api)
+    end
+  end
+
+  defp run(:whoami, opts, api) do
+    case Config.env_token() do
+      # BEAR_TOKEN 優先於憑證檔（不讀檔、不寫檔）。
+      nil ->
+        whoami_from_credentials(opts, api)
+
+      token ->
+        call_userinfo(resolve_issuer(opts), token, opts, api)
+    end
+  end
+
+  defp run(:token, opts, _api) do
+    cond do
+      # BEAR_TOKEN 優先於憑證檔（一次性／CI 用，不寫入）。
+      token = Config.env_token() ->
+        IO.puts(token)
+        0
+
+      true ->
+        token_from_credentials(opts)
+    end
+  end
+
+  defp run(:logout, opts, _api) do
+    case Credentials.delete() do
+      :ok ->
+        if opts[:json] do
+          IO.puts(Jason.encode!(%{ok: true}))
+        else
+          IO.puts("已登出（本機憑證已清除）。")
+          IO.puts("注意：PAT 本身仍在伺服器端有效，如需撤銷請至 Bear 網頁「個人存取權杖」頁面。")
+        end
+
+        0
+
+      {:error, reason} ->
+        fail(opts, "清除憑證失敗：#{inspect(reason)}", 1)
+    end
+  end
+
+  defp run(:status, opts, _api) do
+    env_token = Config.env_token()
+
+    cond do
+      env_token ->
+        issuer = resolve_issuer(opts)
+
+        if opts[:json] do
+          IO.puts(
+            Jason.encode!(%{
+              ok: true,
+              logged_in: true,
+              mode: "env_token",
+              issuer: issuer
+            })
+          )
+        else
+          IO.puts("已登入（BEAR_TOKEN 環境變數）")
+          IO.puts("模式：個人存取權杖（環境變數，不寫入憑證檔）")
+          IO.puts("issuer：#{issuer}")
+        end
+
+        0
+
+      true ->
+        status_from_credentials(opts)
+    end
+  end
+
+  # -- 指令實作輔助 --
+
+  defp whoami_from_credentials(opts, api) do
+    case Credentials.load() do
+      {:ok, creds} ->
+        token = creds["access_token"]
+
+        if blank?(token) do
+          fail(opts, "憑證檔缺少 access_token，請重新 bear login", 7)
+        else
+          call_userinfo(resolve_issuer(opts, creds["issuer"]), token, opts, api)
+        end
+
+      :error ->
+        fail(opts, "未登入（請先執行 bear login）", 3)
+    end
+  end
+
+  defp call_userinfo(issuer, token, opts, api) do
+    if opts[:verbose], do: IO.puts(:stderr, "issuer: #{issuer}")
+
+    case api.(issuer, token) do
+      {:ok, claims} ->
+        if opts[:json] do
+          IO.puts(Jason.encode!(%{ok: true, claims: claims}))
+        else
+          print_claims(claims)
+        end
+
+        0
+
+      {:error, :unauthorized, desc} ->
+        fail(opts, "token 無效或已過期（#{desc}），請重新 bear login", 3)
+
+      {:error, :network, reason} ->
+        fail(opts, "無法連線到 #{issuer}：#{reason}", 6)
+
+      {:error, :server_error, status} ->
+        fail(opts, "伺服器回應 #{status}", 6)
+    end
+  end
+
+  defp token_from_credentials(opts) do
+    case Credentials.load() do
+      {:ok, creds} ->
+        if opts[:refresh] do
+          # 規格 §3.3：PAT 模式下 --refresh 為無效選項，報用法錯誤。
+          fail_token("PAT 模式無 refresh token，--refresh 為無效選項", 2)
+        else
+          case creds["access_token"] do
+            token when is_binary(token) and token != "" ->
+              # token 指令只輸出 token 本體（單行、無前綴），供 pipe 使用。
+              IO.puts(token)
+              0
+
+            _ ->
+              fail_token("憑證檔缺少 access_token，請重新 bear login", 7)
+          end
+        end
+
+      :error ->
+        fail_token("未登入（請先執行 bear login）", 3)
+    end
+  end
+
+  defp status_from_credentials(opts) do
+    case Credentials.load() do
+      {:ok, creds} ->
+        if opts[:json] do
+          IO.puts(
+            Jason.encode!(%{
+              ok: true,
+              logged_in: true,
+              email: creds["email"],
+              issuer: creds["issuer"],
+              mode: "pat"
+            })
+          )
+        else
+          IO.puts("已登入：#{creds["email"] || "(未知)"}")
+          IO.puts("模式：個人存取權杖（PAT）")
+          IO.puts("issuer：#{creds["issuer"]}")
+        end
+
+        0
+
+      :error ->
+        if opts[:json] do
+          IO.puts(Jason.encode!(%{ok: false, logged_in: false, error: "未登入", code: 3}))
+        else
+          IO.puts("未登入")
+        end
+
+        3
+    end
+  end
+
+  # -- 指令實作輔助 --
+
+  defp do_login(opts, token, api) do
+    issuer = resolve_issuer(opts)
+
+    if opts[:verbose], do: IO.puts(:stderr, "issuer: #{issuer}")
+
+    case api.(issuer, token) do
+      {:ok, claims} ->
+        email = claims["email"]
+        creds = %{"issuer" => issuer, "access_token" => token, "email" => email}
+
+        case Credentials.save(creds) do
+          :ok ->
+            if opts[:json] do
+              IO.puts(Jason.encode!(%{ok: true, email: email}))
+            else
+              IO.puts("已登入：#{email || "(無 email claim)"}")
+            end
+
+            0
+
+          {:error, reason} ->
+            fail(opts, "憑證檔寫入失敗：#{inspect(reason)}", 1)
+        end
+
+      {:error, :unauthorized, desc} ->
+        # 規格 §3.1：PAT 無效或已撤銷 → 退出碼 3。
+        fail(opts, "PAT 無效或已撤銷（#{desc}），不寫入任何資料", 3)
+
+      {:error, :network, reason} ->
+        fail(opts, "無法連線到 #{issuer}：#{reason}", 6)
+
+      {:error, :server_error, status} ->
+        fail(opts, "伺服器回應 #{status}", 6)
+    end
+  end
+
+  # -- 輔助 --
+
+  # 優先取 --issuer flag；否則取憑證內記錄的 issuer；最後才回落 config/env/預設。
+  defp resolve_issuer(opts, stored_issuer \\ nil) do
+    opts[:issuer] || stored_issuer || Config.resolve_issuer(nil, opts[:config])
+  end
+
+  defp read_token_from_stdin do
+    IO.read(:stdio, :line) |> to_string() |> String.trim()
+  end
+
+  defp fail(opts, message, code) do
+    if opts[:json] do
+      IO.puts(Jason.encode!(%{ok: false, error: message, code: code}))
+    else
+      IO.puts(:stderr, "錯誤：#{message}")
+    end
+
+    code
+  end
+
+  # token 指令的錯誤一律走 stderr，避免污染 stdout（pipe 的對象）。
+  defp fail_token(message, code) do
+    IO.puts(:stderr, "錯誤：#{message}")
+    code
+  end
+
+  @preferred_claims ~w(sub email name preferred_username nickname picture)
+
+  defp print_claims(claims) do
+    preferred =
+      Enum.filter(@preferred_claims, &Map.has_key?(claims, &1))
+
+    rest =
+      claims
+      |> Map.drop(@preferred_claims)
+      |> Enum.sort_by(fn {k, _} -> to_string(k) end)
+
+    Enum.each(preferred, fn k ->
+      IO.puts("#{String.pad_trailing(k, 20)}: #{format_value(claims[k])}")
+    end)
+
+    Enum.each(rest, fn {k, v} ->
+      IO.puts("#{String.pad_trailing(to_string(k), 20)}: #{format_value(v)}")
+    end)
+  end
+
+  defp format_value(v) when is_binary(v), do: v
+  defp format_value(v) when is_number(v), do: to_string(v)
+  defp format_value(v) when is_boolean(v), do: to_string(v)
+  defp format_value(v) when is_nil(v), do: ""
+  defp format_value(v), do: Jason.encode!(v)
+
+  defp blank?(nil), do: true
+  defp blank?(""), do: true
+  defp blank?(_), do: false
+
+  defp print_help do
+    IO.puts("""
+    Bear CLI — Bear SSO 終端機客戶端
+
+    用法：bear <指令> [選項]
+
+    指令：
+      login --token <PAT>   以個人存取權杖登入（PAT 模式；Device Flow 尚未開放）
+      whoami                顯示目前登入身分
+      token [--refresh]     印出 access token（PAT 模式下 --refresh 為用法錯誤）
+      logout                登出（清除本機憑證）
+      status                顯示登入狀態
+
+    全域選項：
+      --issuer URL          Bear（OIDC Provider）位址（預設 https://alterminal.com）
+      --config PATH         設定檔路徑（預設 ~/.config/bear/config.json）
+      --json                機器可讀輸出（JSON）
+      -v, --verbose         顯示詳細日誌
+      -h, --help            顯示說明
+      --version             顯示版本
+
+    環境變數：
+      BEAR_TOKEN            一次性／CI 用的 PAT；提供後 whoami/token/status 優先
+                            使用，不寫入憑證檔
+    """)
+  end
+end

lib/bear_cli/config.ex

@@ -0,0 +1,96 @@
+defmodule BearCli.Config do
+  @moduledoc """
+  設定檔與憑證檔的路徑及讀取。
+
+  設定優先序：CLI flag ＞ 環境變數（`BEAR_ISSUER`）＞ 設定檔 ＞ 內建預設。
+  """
+
+  @default_issuer "https://alterminal.com"
+
+  @doc "內建預設 issuer。"
+  def default_issuer, do: @default_issuer
+
+  @doc """
+  設定檔路徑：`~/.config/bear/config.json`（可用 `BEAR_CONFIG` 覆寫）。
+  """
+  def config_path do
+    System.get_env("BEAR_CONFIG") || Path.join(config_home(), "config.json")
+  end
+
+  @doc """
+  憑證檔路徑：`~/.local/state/bear/credentials.json`（可用 `BEAR_CREDENTIALS` 覆寫）。
+  """
+  def credentials_path do
+    System.get_env("BEAR_CREDENTIALS") || Path.join(state_home(), "credentials.json")
+  end
+
+  defp config_home do
+    base =
+      System.get_env("XDG_CONFIG_HOME") ||
+        Path.join(System.user_home!(), ".config")
+
+    Path.join(base, "bear")
+  end
+
+  defp state_home do
+    base =
+      System.get_env("XDG_STATE_HOME") ||
+        Path.join(System.user_home!(), ".local/state")
+
+    Path.join(base, "bear")
+  end
+
+  @doc """
+  讀取設定檔，回傳 `{:ok, map}` 或 `:error`（檔案不存在／JSON 損毀）。
+  """
+  def read_config(path \\ config_path()) do
+    case File.read(path) do
+      {:ok, content} -> Jason.decode(content)
+      {:error, _} -> :error
+    end
+  end
+
+  @doc """
+  解析最終 issuer，依序取第一個非空白值：
+
+  1. `cli_issuer`（`--issuer` flag）
+  2. `BEAR_ISSUER` 環境變數
+  3. 設定檔的 `issuer` 欄位（讀自 `config_path_override` 或預設路徑）
+  4. 內建預設 `https://alterminal.com`
+  """
+  def resolve_issuer(cli_issuer, config_path_override \\ nil) do
+    path = config_path_override || config_path()
+
+    config =
+      case read_config(path) do
+        {:ok, map} when is_map(map) -> map
+        _ -> %{}
+      end
+
+    Enum.find(
+      [
+        cli_issuer,
+        System.get_env("BEAR_ISSUER"),
+        config["issuer"],
+        @default_issuer
+      ],
+      &(not blank?(&1))
+    )
+  end
+
+  @doc """
+  `BEAR_TOKEN` 環境變數（一次性／CI 用的 PAT）。
+
+  提供後優先於本機憑證檔，但不寫入憑證檔。空值或純空白視為未提供。
+  """
+  def env_token do
+    case System.get_env("BEAR_TOKEN") do
+      nil -> nil
+      token -> if blank?(String.trim(token)), do: nil, else: String.trim(token)
+    end
+  end
+
+  defp blank?(nil), do: true
+  defp blank?(""), do: true
+  defp blank?(_), do: false
+end

lib/bear_cli/credentials.ex

@@ -0,0 +1,87 @@
+defmodule BearCli.Credentials do
+  @moduledoc """
+  本機憑證檔的讀寫（0600，原子寫入、防 symlink 攻擊）。
+
+  憑證檔結構（JSON）：
+
+      {"issuer": "https://alterminal.com", "access_token": "<PAT>", "email": "..."}
+
+  PAT 模式沒有 refresh token，`access_token` 即個人存取權杖本身。
+  """
+
+  alias BearCli.Config
+
+  @doc """
+  載入憑證，回傳 `{:ok, map}` 或 `:error`（不存在／JSON 損毀）。
+  """
+  def load(path \\ Config.credentials_path()) do
+    case File.read(path) do
+      {:ok, content} ->
+        case Jason.decode(content) do
+          {:ok, map} when is_map(map) -> {:ok, map}
+          _ -> :error
+        end
+
+      {:error, _} ->
+        :error
+    end
+  end
+
+  @doc """
+  寫入憑證（原子、0600）。建立父目錄（0700）。回傳 `:ok` 或 `{:error, reason}`。
+  """
+  def save(map, path \\ Config.credentials_path()) do
+    json = Jason.encode!(map)
+
+    with :ok <- ensure_parent_dir(path),
+         {:ok, tmp} <- write_temp(path, json) do
+      # rename(2) 會原子地取代目標（包含取代 symlink 本身，而非其指向的檔案）。
+      File.rename(tmp, path)
+    else
+      {:error, _} = error -> error
+    end
+  end
+
+  @doc """
+  刪除憑證檔；檔案不存在也算成功。
+  """
+  def delete(path \\ Config.credentials_path()) do
+    case File.rm(path) do
+      :ok -> :ok
+      {:error, :enoent} -> :ok
+      {:error, reason} -> {:error, reason}
+    end
+  end
+
+  defp ensure_parent_dir(path) do
+    dir = Path.dirname(path)
+    File.mkdir_p(dir)
+
+    # 目錄權限 0700 為 best-effort（例如憑證路徑落在 /tmp 等共享目錄時無法 chmod，
+    # 忽略即可；真正的保護是憑證檔本身的 0600）。
+    _ = File.chmod(dir, 0o700)
+    :ok
+  end
+
+  defp write_temp(path, json) do
+    dir = Path.dirname(path)
+    tmp = Path.join(dir, ".credentials.#{System.unique_integer([:positive])}.tmp")
+
+    result =
+      with {:ok, io} <- File.open(tmp, [:write, :exclusive, :binary]),
+           :ok <- IO.binwrite(io, json),
+           :ok <- File.close(io),
+           :ok <- File.chmod(tmp, 0o600) do
+        {:ok, tmp}
+      end
+
+    case result do
+      {:ok, _} = ok ->
+        ok
+
+      {:error, _} = error ->
+        _ = File.rm(tmp)
+        error
+    end
+  end
+end

mix.exs

@@ -0,0 +1,49 @@
+defmodule BearCli.MixProject do
+  use Mix.Project
+
+  def project do
+    [
+      app: :bear_cli,
+      version: "0.1.0",
+      elixir: "~> 1.17",
+      start_permanent: Mix.env() == :prod,
+      deps: deps(),
+      escript: escript(),
+      aliases: aliases()
+    ]
+  end
+
+  def application do
+    [
+      extra_applications: [:logger]
+    ]
+  end
+
+  def cli do
+    [
+      preferred_envs: [precommit: :test]
+    ]
+  end
+
+  # escript 打包：單檔可執行，主模組為 BearCli.CLI。
+  defp escript do
+    [
+      main_module: BearCli.CLI,
+      name: "bear"
+    ]
+  end
+
+  defp deps do
+    [
+      # HTTP 一律使用 Req（與 bear 主專案一致）。
+      {:req, "~> 0.5"},
+      {:jason, "~> 1.2"}
+    ]
+  end
+
+  defp aliases do
+    [
+      precommit: ["compile --warnings-as-errors", "format", "test"]
+    ]
+  end
+end

mix.lock

@@ -0,0 +1,11 @@
+%{
+  "finch": {:hex, :finch, "0.23.0", "e3f9287ac25a8832f848b144c2b57346aac65b205e2e0629a52adfe6507fd837", [:mix], [{:mime, "~> 1.0 or ~> 2.0", [hex: :mime, repo: "hexpm", optional: false]}, {:mint, "~> 1.8", [hex: :mint, repo: "hexpm", optional: false]}, {:nimble_options, "~> 0.4 or ~> 1.0", [hex: :nimble_options, repo: "hexpm", optional: false]}, {:nimble_pool, "~> 1.1", [hex: :nimble_pool, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "80e58d3f936f57e3fdf404f83a3642897ae6d9fb642934e46da4d8fe761b99d5"},
+  "hpax": {:hex, :hpax, "1.0.4", "777de5d433b0fbdc7c418159c8055910faa8047ffdb3d6b31098d2a46cd7685c", [:mix], [], "hexpm", "afc7cb142ebcc2d01ce7816190b98ce5dd49e799111b24249f3443d730f377ca"},
+  "jason": {:hex, :jason, "1.4.5", "2e3a008590b0b8d7388c20293e9dcc9cf3e5d642fd2a114e4cbbb52e595d940a", [:mix], [{:decimal, "~> 1.0 or ~> 2.0 or ~> 3.0", [hex: :decimal, repo: "hexpm", optional: true]}], "hexpm", "b0c823996102bcd0239b3c2444eb00409b72f6a140c1950bc8b457d836b30684"},
+  "mime": {:hex, :mime, "2.0.7", "b8d739037be7cd402aee1ba0306edfdef982687ee7e9859bee6198c1e7e2f128", [:mix], [], "hexpm", "6171188e399ee16023ffc5b76ce445eb6d9672e2e241d2df6050f3c771e80ccd"},
+  "mint": {:hex, :mint, "1.9.3", "3337184d69179695c7a9f1714d92c11e629d36c8c037a21cf490131d3d150554", [:mix], [{:castore, "~> 0.1.0 or ~> 1.0", [hex: :castore, repo: "hexpm", optional: true]}, {:hpax, "~> 0.1.1 or ~> 0.2.0 or ~> 1.0", [hex: :hpax, repo: "hexpm", optional: false]}], "hexpm", "5f7c9342480c069dbbc4eeac3490303c9e01870ff01a7f1d29b6107054fc1e74"},
+  "nimble_options": {:hex, :nimble_options, "1.1.1", "e3a492d54d85fc3fd7c5baf411d9d2852922f66e69476317787a7b2bb000a61b", [:mix], [], "hexpm", "821b2470ca9442c4b6984882fe9bb0389371b8ddec4d45a9504f00a66f650b44"},
+  "nimble_pool": {:hex, :nimble_pool, "1.1.0", "bf9c29fbdcba3564a8b800d1eeb5a3c58f36e1e11d7b7fb2e084a643f645f06b", [:mix], [], "hexpm", "af2e4e6b34197db81f7aad230c1118eac993acc0dae6bc83bac0126d4ae0813a"},
+  "req": {:hex, :req, "0.7.4", "23e9ffec17de032a46a4b15ed65c09793893bf4a7c680f4bbf6227fce6bdf74d", [:mix], [{:brotli, "~> 0.3.1", [hex: :brotli, repo: "hexpm", optional: true]}, {:finch, "~> 0.21", [hex: :finch, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}, {:mime, "~> 2.0.6 or ~> 2.1", [hex: :mime, repo: "hexpm", optional: false]}, {:nimble_csv, "~> 1.0", [hex: :nimble_csv, repo: "hexpm", optional: true]}, {:plug, "~> 1.0", [hex: :plug, repo: "hexpm", optional: true]}], "hexpm", "4b192d63253e8dcc6221ef992ea9ebef7d3555166e8423aa5b553e86bc3c69a2"},
+  "telemetry": {:hex, :telemetry, "1.4.2", "a0cb522801dffb1c49fe6e30561badffc7b6d0e180db1300df759faa22062855", [:rebar3], [], "hexpm", "928f6495066506077862c0d1646609eed891a4326bee3126ba54b60af61febb1"},
+}

test/bear_cli/cli_test.exs

@@ -0,0 +1,299 @@
+defmodule BearCli.CLITest do
+  use ExUnit.Case, async: false
+
+  alias BearCli.CLI
+
+  setup do
+    old_creds = System.get_env("BEAR_CREDENTIALS")
+
+    on_exit(fn ->
+      restore_env("BEAR_CREDENTIALS", old_creds)
+    end)
+
+    :ok
+  end
+
+  describe "parse/1" do
+    test "no args -> help" do
+      assert {:help, %{}} = CLI.parse([])
+    end
+
+    test "--version" do
+      assert {:version, %{}} = CLI.parse(["--version"])
+    end
+
+    test "-h alias -> help" do
+      assert {:help, %{}} = CLI.parse(["-h"])
+    end
+
+    test "login --token X" do
+      assert {:ok, :login, %{token: "X"}} = CLI.parse(["login", "--token", "X"])
+    end
+
+    test "global option before command" do
+      assert {:ok, :whoami, %{json: true}} = CLI.parse(["--json", "whoami"])
+    end
+
+    test "global option after command" do
+      assert {:ok, :status, %{json: true}} = CLI.parse(["status", "--json"])
+    end
+
+    test "token --refresh" do
+      assert {:ok, :token, %{refresh: true}} = CLI.parse(["token", "--refresh"])
+    end
+
+    test "issuer flag is captured" do
+      assert {:ok, :whoami, %{issuer: "https://x"}} =
+               CLI.parse(["whoami", "--issuer", "https://x"])
+    end
+
+    test "unknown command -> usage error" do
+      assert {:error, _, 2} = CLI.parse(["frobnicate"])
+    end
+
+    test "unknown option -> usage error" do
+      assert {:error, _, 2} = CLI.parse(["--bogus"])
+    end
+  end
+
+  describe "dispatch/2 (injected api)" do
+    test "login --token writes credentials and prints email" do
+      path = tmp_path()
+      on_exit(fn -> File.rm(path) end)
+      System.put_env("BEAR_CREDENTIALS", path)
+
+      {code, out} =
+        ExUnit.CaptureIO.with_io(fn ->
+          CLI.dispatch(CLI.parse(["login", "--token", "good"]), api: fake_api())
+        end)
+
+      assert code == 0
+      assert out =~ "已登入：alice@example.com"
+      assert {:ok, %{"access_token" => "good"}} = BearCli.Credentials.load(path)
+    end
+
+    test "login with invalid token exits 3" do
+      System.put_env("BEAR_CREDENTIALS", tmp_path())
+
+      {code, err} =
+        ExUnit.CaptureIO.with_io(
+          :stderr,
+          "",
+          fn -> CLI.dispatch(CLI.parse(["login", "--token", "bad"]), api: fake_api()) end
+        )
+
+      assert code == 3
+      assert err =~ "PAT 無效"
+    end
+
+    test "login without --token points to Device Flow being unavailable" do
+      System.put_env("BEAR_CREDENTIALS", tmp_path())
+
+      {code, err} =
+        ExUnit.CaptureIO.with_io(
+          :stderr,
+          "",
+          fn -> CLI.dispatch(CLI.parse(["login"]), api: fake_api()) end
+        )
+
+      assert code == 2
+      assert err =~ "Device Flow"
+    end
+
+    test "whoami when not logged in exits 3" do
+      System.put_env("BEAR_CREDENTIALS", "/nonexistent/credentials.json")
+
+      {code, err} =
+        ExUnit.CaptureIO.with_io(
+          :stderr,
+          "",
+          fn -> CLI.dispatch(CLI.parse(["whoami"]), api: fake_api()) end
+        )
+
+      assert code == 3
+      assert err =~ "未登入"
+    end
+
+    test "whoami prints claims" do
+      path = tmp_path()
+      on_exit(fn -> File.rm(path) end)
+      System.put_env("BEAR_CREDENTIALS", path)
+      BearCli.Credentials.save(%{"issuer" => "https://x", "access_token" => "good"}, path)
+
+      {code, out} =
+        ExUnit.CaptureIO.with_io(fn ->
+          CLI.dispatch(CLI.parse(["whoami"]), api: fake_api())
+        end)
+
+      assert code == 0
+      assert out =~ "email"
+      assert out =~ "alice@example.com"
+    end
+
+    test "token prints only the token" do
+      path = tmp_path()
+      on_exit(fn -> File.rm(path) end)
+      System.put_env("BEAR_CREDENTIALS", path)
+      BearCli.Credentials.save(%{"issuer" => "https://x", "access_token" => "good-token"}, path)
+
+      {code, out} =
+        ExUnit.CaptureIO.with_io(fn ->
+          CLI.dispatch(CLI.parse(["token"]), api: fake_api())
+        end)
+
+      assert code == 0
+      assert String.trim(out) == "good-token"
+    end
+
+    test "token --refresh is a usage error in PAT mode" do
+      path = tmp_path()
+      on_exit(fn -> File.rm(path) end)
+      System.put_env("BEAR_CREDENTIALS", path)
+      BearCli.Credentials.save(%{"issuer" => "https://x", "access_token" => "good-token"}, path)
+
+      {code, err} =
+        ExUnit.CaptureIO.with_io(
+          :stderr,
+          "",
+          fn -> CLI.dispatch(CLI.parse(["token", "--refresh"]), api: fake_api()) end
+        )
+
+      assert code == 2
+      assert err =~ "--refresh"
+    end
+
+    test "status when logged in exits 0 and reports PAT mode" do
+      path = tmp_path()
+      on_exit(fn -> File.rm(path) end)
+      System.put_env("BEAR_CREDENTIALS", path)
+
+      BearCli.Credentials.save(
+        %{"issuer" => "https://x", "email" => "a@b.c", "access_token" => "t"},
+        path
+      )
+
+      {code, out} =
+        ExUnit.CaptureIO.with_io(fn ->
+          CLI.dispatch(CLI.parse(["status"]), api: fake_api())
+        end)
+
+      assert code == 0
+      assert out =~ "已登入：a@b.c"
+      assert out =~ "PAT"
+    end
+
+    test "logout clears credentials" do
+      path = tmp_path()
+      on_exit(fn -> File.rm(path) end)
+      System.put_env("BEAR_CREDENTIALS", path)
+      BearCli.Credentials.save(%{"issuer" => "https://x", "access_token" => "t"}, path)
+
+      {code, _out} =
+        ExUnit.CaptureIO.with_io(fn ->
+          CLI.dispatch(CLI.parse(["logout"]), api: fake_api())
+        end)
+
+      assert code == 0
+      assert :error == BearCli.Credentials.load(path)
+    end
+  end
+
+  describe "BEAR_TOKEN environment variable" do
+    setup do
+      old_creds = System.get_env("BEAR_CREDENTIALS")
+      old_token = System.get_env("BEAR_TOKEN")
+
+      on_exit(fn ->
+        restore_env("BEAR_CREDENTIALS", old_creds)
+        restore_env("BEAR_TOKEN", old_token)
+      end)
+
+      :ok
+    end
+
+    test "whoami uses BEAR_TOKEN without credentials file" do
+      System.put_env("BEAR_CREDENTIALS", "/nonexistent/credentials.json")
+      System.put_env("BEAR_TOKEN", "good")
+
+      {code, out} =
+        ExUnit.CaptureIO.with_io(fn ->
+          CLI.dispatch(CLI.parse(["whoami"]), api: fake_api())
+        end)
+
+      assert code == 0
+      assert out =~ "alice@example.com"
+    end
+
+    test "whoami with invalid BEAR_TOKEN exits 3" do
+      System.put_env("BEAR_CREDENTIALS", "/nonexistent/credentials.json")
+      System.put_env("BEAR_TOKEN", "bad")
+
+      {code, err} =
+        ExUnit.CaptureIO.with_io(
+          :stderr,
+          "",
+          fn -> CLI.dispatch(CLI.parse(["whoami"]), api: fake_api()) end
+        )
+
+      assert code == 3
+      assert err =~ "token 無效"
+    end
+
+    test "token prints BEAR_TOKEN" do
+      System.put_env("BEAR_CREDENTIALS", "/nonexistent/credentials.json")
+      System.put_env("BEAR_TOKEN", "env-pat")
+
+      {code, out} =
+        ExUnit.CaptureIO.with_io(fn ->
+          CLI.dispatch(CLI.parse(["token"]), api: fake_api())
+        end)
+
+      assert code == 0
+      assert String.trim(out) == "env-pat"
+    end
+
+    test "status reports env token mode" do
+      System.put_env("BEAR_CREDENTIALS", "/nonexistent/credentials.json")
+      System.put_env("BEAR_TOKEN", "env-pat")
+
+      {code, out} =
+        ExUnit.CaptureIO.with_io(fn ->
+          CLI.dispatch(CLI.parse(["status"]), api: fake_api())
+        end)
+
+      assert code == 0
+      assert out =~ "BEAR_TOKEN"
+    end
+
+    test "blank BEAR_TOKEN is ignored" do
+      System.put_env("BEAR_CREDENTIALS", "/nonexistent/credentials.json")
+      System.put_env("BEAR_TOKEN", "   ")
+
+      {code, _err} =
+        ExUnit.CaptureIO.with_io(
+          :stderr,
+          "",
+          fn -> CLI.dispatch(CLI.parse(["whoami"]), api: fake_api()) end
+        )
+
+      assert code == 3
+    end
+  end
+
+  defp fake_api do
+    fn _issuer, token ->
+      case token do
+        "good" -> {:ok, %{"sub" => "u1", "email" => "alice@example.com", "name" => "Alice"}}
+        "bad" -> {:error, :unauthorized, "invalid_token"}
+        _ -> {:error, :server_error, 500}
+      end
+    end
+  end
+
+  defp tmp_path do
+    Path.join(System.tmp_dir!(), "bear_cli_cli_#{System.unique_integer([:positive])}.json")
+  end
+
+  defp restore_env(key, nil), do: System.delete_env(key)
+  defp restore_env(key, value), do: System.put_env(key, value)
+end

test/bear_cli/config_test.exs

@@ -0,0 +1,63 @@
+defmodule BearCli.ConfigTest do
+  use ExUnit.Case, async: false
+
+  alias BearCli.Config
+
+  @nonexistent "/nonexistent/bear_cli_config.json"
+
+  setup do
+    old_issuer = System.get_env("BEAR_ISSUER")
+    old_config = System.get_env("BEAR_CONFIG")
+
+    on_exit(fn ->
+      restore_env("BEAR_ISSUER", old_issuer)
+      restore_env("BEAR_CONFIG", old_config)
+    end)
+
+    System.delete_env("BEAR_ISSUER")
+    System.put_env("BEAR_CONFIG", @nonexistent)
+
+    :ok
+  end
+
+  test "defaults to the built-in issuer when nothing else is set" do
+    assert Config.resolve_issuer(nil) == "https://alterminal.com"
+  end
+
+  test "CLI flag takes precedence over everything" do
+    System.put_env("BEAR_ISSUER", "https://env.example.com")
+    assert Config.resolve_issuer("https://flag.example.com") == "https://flag.example.com"
+  end
+
+  test "BEAR_ISSUER env wins over config and default" do
+    System.put_env("BEAR_ISSUER", "https://env.example.com")
+    assert Config.resolve_issuer(nil) == "https://env.example.com"
+  end
+
+  test "config file issuer wins over default" do
+    path = write_config(%{"issuer" => "https://config.example.com"})
+
+    on_exit(fn -> File.rm(path) end)
+
+    assert Config.resolve_issuer(nil, path) == "https://config.example.com"
+  end
+
+  test "config path override is honored" do
+    path = write_config(%{"issuer" => "https://override.example.com"})
+
+    on_exit(fn -> File.rm(path) end)
+
+    assert Config.resolve_issuer(nil, path) == "https://override.example.com"
+  end
+
+  defp write_config(map) do
+    path =
+      Path.join(System.tmp_dir!(), "bear_cli_config_#{System.unique_integer([:positive])}.json")
+
+    File.write!(path, Jason.encode!(map))
+    path
+  end
+
+  defp restore_env(key, nil), do: System.delete_env(key)
+  defp restore_env(key, value), do: System.put_env(key, value)
+end

test/bear_cli/credentials_test.exs

@@ -0,0 +1,62 @@
+defmodule BearCli.CredentialsTest do
+  use ExUnit.Case, async: true
+
+  alias BearCli.Credentials
+
+  test "save/load round-trips JSON" do
+    path = tmp_path()
+    on_exit(fn -> File.rm(path) end)
+
+    assert :ok ==
+             Credentials.save(
+               %{"issuer" => "x", "access_token" => "tok", "email" => "a@b.c"},
+               path
+             )
+
+    assert {:ok, %{"access_token" => "tok", "email" => "a@b.c"}} = Credentials.load(path)
+  end
+
+  test "save creates the file with 0600 permissions" do
+    path = tmp_path()
+    on_exit(fn -> File.rm(path) end)
+    :ok = Credentials.save(%{"access_token" => "tok"}, path)
+
+    mode = File.stat!(path).mode
+    assert Bitwise.band(mode, 0o777) == 0o600
+  end
+
+  test "save creates the parent directory" do
+    base = Path.join(System.tmp_dir!(), "bear_cli_nested_#{System.unique_integer([:positive])}")
+    path = Path.join([base, "sub", "credentials.json"])
+    on_exit(fn -> File.rm_rf(base) end)
+
+    :ok = Credentials.save(%{"a" => "b"}, path)
+    assert File.regular?(path)
+  end
+
+  test "load returns :error for a missing file" do
+    assert :error == Credentials.load("/nonexistent/credentials.json")
+  end
+
+  test "load returns :error for corrupt JSON" do
+    path = tmp_path()
+    on_exit(fn -> File.rm(path) end)
+    File.write!(path, "{not json")
+
+    assert :error == Credentials.load(path)
+  end
+
+  test "delete removes the file and is idempotent" do
+    path = tmp_path()
+    on_exit(fn -> File.rm(path) end)
+    :ok = Credentials.save(%{"a" => "b"}, path)
+
+    assert :ok == Credentials.delete(path)
+    assert :error == Credentials.load(path)
+    assert :ok == Credentials.delete(path)
+  end
+
+  defp tmp_path do
+    Path.join(System.tmp_dir!(), "bear_cli_creds_#{System.unique_integer([:positive])}.json")
+  end
+end

test/test_helper.exs

@@ -0,0 +1 @@
+ExUnit.start()