feat(ai-term): pick the agent runtime at session launch

A fresh agent session now asks which runtime to run: claude, codex, or any local ollama model via codex --oss. RET keeps claude, so the common launch stays Enter-Enter. Reattaches and redisplays never ask. The picker fires only when neither a live agent buffer nor a surviving tmux session exists.

I mirrored the runtime names and launch strings from the bin/ai launcher so the two stay one mental model, and the choice list itself comes from "ai --print-runtimes" when that launcher is installed, reusing its live ollama scan and dead-server timeout. A static claude-first list stands in without it. The explicit --local-provider=ollama flag is deliberate: configuring the provider through config.toml silently does nothing.

The chosen command threads through show-or-create into the tmux launch line. On reattach, tmux new-session -A ignores it, so no reattach path changes behavior. cj/ai-term-agent-command keeps its meaning as the claude runtime's full line.

Thirteen tests cover the runtime-to-command map, the print-runtimes parsing, the launcher fallback, and the launch-command override.

1 files changed, 136 insertions, 0 deletions

diff --git a/tests/test-ai-term--runtime.el b/tests/test-ai-term--runtime.el
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+;;; test-ai-term--runtime.el --- Tests for the ai-term runtime selection -*- lexical-binding: t; -*-
+
+;;; Commentary:
+;; Multi-backend launch: a fresh agent session can run Claude, Codex, or a
+;; local model through codex --oss (ollama).  The runtime names and launch
+;; strings mirror the rulesets bin/ai launcher so the two stay one mental
+;; model: "claude", "codex", and "local:<model>".
+;;
+;; Pure pieces tested here:
+;; - `cj/--ai-term-runtime-command' maps a runtime name to the full shell
+;;   command (agent CLI + the shared opening prompt).
+;; - `cj/--ai-term-parse-runtime-lines' parses `ai --print-runtimes' output
+;;   into (NAME . LABEL) choices.
+;; - `cj/--ai-term-runtime-choices' shells out to `ai' at its boundary
+;;   (mocked here) and falls back to the static list when `ai' is absent.
+;; The interactive picker is a thin completing-read wrapper and is not
+;; tested (Interactive vs Internal split).
+
+;;; Code:
+
+(require 'ert)
+(require 'cl-lib)
+
+(add-to-list 'load-path (expand-file-name "modules" user-emacs-directory))
+(require 'ai-term)
+
+;;; ------------------------- runtime -> command ------------------------------
+
+(ert-deftest test-ai-term-runtime-command-claude-is-agent-command ()
+  "Normal: \"claude\" (and nil) return `cj/ai-term-agent-command' verbatim."
+  (let ((cj/ai-term-agent-command "claude \"do the thing\""))
+    (should (equal (cj/--ai-term-runtime-command "claude")
+                   "claude \"do the thing\""))
+    (should (equal (cj/--ai-term-runtime-command nil)
+                   "claude \"do the thing\""))))
+
+(ert-deftest test-ai-term-runtime-command-codex-composes-prompt ()
+  "Normal: \"codex\" is the codex CLI plus the shared opening prompt."
+  (let ((cj/ai-term-agent-prompt "read the protocols"))
+    (should (equal (cj/--ai-term-runtime-command "codex")
+                   (concat "codex " (shell-quote-argument "read the protocols"))))))
+
+(ert-deftest test-ai-term-runtime-command-local-model ()
+  "Normal: \"local:<model>\" runs codex --oss against that ollama model.
+The model is shell-quoted, and POSIX `shell-quote-argument' backslash-escapes
+the colons, so the assertion matches the quoted form."
+  (let ((cj/ai-term-agent-prompt "read the protocols"))
+    (let ((cmd (cj/--ai-term-runtime-command "local:gpt-oss:120b")))
+      (should (string-prefix-p "codex --oss --local-provider=ollama -m " cmd))
+      (should (string-match-p
+               (regexp-quote (shell-quote-argument "gpt-oss:120b")) cmd))
+      (should (string-suffix-p (shell-quote-argument "read the protocols") cmd)))))
+
+(ert-deftest test-ai-term-runtime-command-boundary-empty-model ()
+  "Boundary: \"local:\" with no model is rejected, not launched half-formed."
+  (should-error (cj/--ai-term-runtime-command "local:") :type 'user-error))
+
+(ert-deftest test-ai-term-runtime-command-error-unknown-runtime ()
+  "Error: an unknown runtime name signals a `user-error' naming it."
+  (should-error (cj/--ai-term-runtime-command "gemini") :type 'user-error)
+  (condition-case err
+      (cj/--ai-term-runtime-command "gemini")
+    (user-error (should (string-match-p "gemini" (cadr err))))))
+
+;;; --------------------------- choice-list parsing ---------------------------
+
+(ert-deftest test-ai-term-parse-runtime-lines-normal ()
+  "Normal: `ai --print-runtimes' lines parse into (NAME . LABEL) pairs."
+  (should (equal (cj/--ai-term-parse-runtime-lines
+                  "claude — Claude Code\ncodex — ChatGPT (Codex CLI)\nlocal:gpt-oss:120b — ollama\n")
+                 '(("claude" . "Claude Code")
+                   ("codex" . "ChatGPT (Codex CLI)")
+                   ("local:gpt-oss:120b" . "ollama")))))
+
+(ert-deftest test-ai-term-parse-runtime-lines-boundary-junk ()
+  "Boundary: blank lines and lines without a separator are dropped."
+  (should (equal (cj/--ai-term-parse-runtime-lines
+                  "\nclaude — Claude Code\nwarning: something\n\n")
+                 '(("claude" . "Claude Code")))))
+
+(ert-deftest test-ai-term-parse-runtime-lines-boundary-empty ()
+  "Boundary: empty output parses to nil."
+  (should (null (cj/--ai-term-parse-runtime-lines ""))))
+
+;;; ------------------------------ choice list --------------------------------
+
+(ert-deftest test-ai-term-runtime-choices-uses-ai-launcher ()
+  "Normal: when the `ai' launcher exists, its runtime list is the choice list."
+  (cl-letf (((symbol-function 'executable-find)
+             (lambda (prog &rest _) (when (equal prog "ai") "/usr/bin/ai")))
+            ((symbol-function 'process-file)
+             (lambda (_prog _infile buffer _display &rest _args)
+               (with-current-buffer (cond ((eq buffer t) (current-buffer))
+                                          ((consp buffer) (car buffer))
+                                          (t buffer))
+                 (insert "claude — Claude Code\nlocal:q — ollama\n"))
+               0)))
+    (should (equal (cj/--ai-term-runtime-choices)
+                   '(("claude" . "Claude Code") ("local:q" . "ollama"))))))
+
+(ert-deftest test-ai-term-runtime-choices-fallback-without-ai ()
+  "Boundary: with no `ai' launcher, the static claude-first list stands."
+  (cl-letf (((symbol-function 'executable-find) (lambda (&rest _) nil)))
+    (let ((choices (cj/--ai-term-runtime-choices)))
+      (should (equal (caar choices) "claude"))
+      (should (assoc "codex" choices)))))
+
+(ert-deftest test-ai-term-runtime-choices-error-ai-fails ()
+  "Error: a nonzero exit from `ai' falls back instead of erroring."
+  (cl-letf (((symbol-function 'executable-find)
+             (lambda (prog &rest _) (when (equal prog "ai") "/usr/bin/ai")))
+            ((symbol-function 'process-file) (lambda (&rest _) 1)))
+    (should (equal (caar (cj/--ai-term-runtime-choices)) "claude"))))
+
+;;; --------------------- launch command takes an override --------------------
+
+(ert-deftest test-ai-term-launch-command-runtime-override ()
+  "Normal: an explicit agent command is embedded instead of the default.
+The inner command is shell-quoted by the launch builder, so the assertion
+matches the quoted form."
+  (let ((cj/ai-term-agent-command "claude default"))
+    (let ((cmd (cj/--ai-term-launch-command "/tmp/proj" "codex prompted")))
+      (should (string-match-p
+               (regexp-quote (shell-quote-argument "codex prompted; exec bash"))
+               cmd))
+      (should-not (string-match-p "claude" cmd)))))
+
+(ert-deftest test-ai-term-launch-command-no-override-falls-back ()
+  "Boundary: without an override the configured agent command is used."
+  (let ((cj/ai-term-agent-command "claude default"))
+    (should (string-match-p
+             (regexp-quote (shell-quote-argument "claude default; exec bash"))
+             (cj/--ai-term-launch-command "/tmp/proj")))))
+
+(provide 'test-ai-term--runtime)
+;;; test-ai-term--runtime.el ends here