feat(newos4): register `test` / `[` so chains decide locally instead of asking a model (v4.6.135)

`[ -f "/qt.txt" ] && echo exists` — the probe that closed the v4.6.132 batch — was not a shell test
at all: both commands were unregistered, so the line fell through to the AI fallback and a model was
asked whether a file exists. `_evalTest()` has implemented `-f -d -e -z -n ! = !=` for the if/while
parser since the script runner was written; only the command was missing.

  * `test` and `[` registered in ShellModule. Success resolves silently; false rejects with a
    `silent` error so `&&`/`||` skip it — POSIX prints nothing on exit 1.
  * `[` requires the closing bracket (`[ : missing ']'`), and that message is NOT silent.
  * `test` already names the on-demand regression-suite runner ("test auto" / "test list" in
    help.html). A argv that does not look like a test expression (`-f`/`-d`/`-e`/`-z`/`-n`/`!`,
    or `a = b` / `a != b`) is delegated to the handler registered before us, so `test auto`
    still runs the suite and the two meanings cannot collide.
  * terminal.dispatchCommand() now honours `err.silent` — without it a top-level `test -f /nope`
    printed `Error in ShellModule.test:` (measured on v4.6.134, fixed in v4.6.135).
  * help.html documents the bracket form next to the existing `test` row.

Three tags were minted minutes apart — v4.6.133 (commands), v4.6.134 (suite delegation),
v4.6.135 (silent top-level) — each a real cache-bust for a fix that superseded the previous build;
the net change is this commit.

Verification
  node modules/test/test-shell-test-cmd.js -> 24/24 pass (RED against HEAD: "test command
      registered" fails, "m.commands.test is not a function")
  node modules/test/test-pipe-guard.js     -> all seven flags true
  node modules/test/test-parse-args.js     -> 28/28 · daily job -> node tests 22/22 pass
  newos4-maintain.py -> atlas 355 commands (was 354), modules-index 349, help 364/364
  live v4.6.135, read from the terminal DOM:
    [ -f /qt.txt ] && echo F135          -> F135
    test -f /nope || echo M135           -> M135
    [ -d /nope ] && echo BAD || echo N134-> N134   (false branch skipped, nothing printed)
    test                                 -> no output (suite not loaded; POSIX false)
    test -f /nope                        -> no output
    js "a b".length | wc -c              -> 1       (v4.6.132 pipe fix still intact)
  The AI fallback is no longer reachable for a bracketed file test.

9 files changed, 321 insertions, 38 deletions

diff --git a/course/atlas.json b/course/atlas.json
index 4eeeff4..341ddb3 100644
--- a/course/atlas.json
+++ b/course/atlas.json
@@ -1,6 +1,6 @@
 {
- "version": "2026-10-21T23:46:07Z",
- "source_hash": "fdf2b4d2aaf3dbc0",
+ "version": "2026-10-29T11:53:19Z",
+ "source_hash": "9f5f08a8dd1b7f05",
  "commands": {
   "a2a-ack": {
    "module": "module-agent-registry",
@@ -587,6 +587,15 @@
    "builtin": false,
    "example": "contract-register"
   },
+  "cost": {
+   "module": "module-billing",
+   "file": "modules/core/module-billing.js",
+   "tier": "core-bundle",
+   "category": "general",
+   "desc": "cost [on|off] — AI prices, today's free-message allowance and this session's spend",
+   "builtin": false,
+   "example": "cost"
+  },
   "course": {
    "module": "course",
    "file": "modules/ext/course.js",
@@ -938,6 +947,33 @@
    "builtin": false,
    "example": "factory-reset-old"
   },
+  "feedback": {
+   "module": "module-debug-supervisor",
+   "file": "modules/core/module-debug-supervisor.js",
+   "tier": "core-bundle",
+   "category": "general",
+   "desc": "feedback <message> — Send feedback to the WebX11 maintenance agent",
+   "builtin": false,
+   "example": "feedback"
+  },
+  "feedback-admin": {
+   "module": "module-debug-supervisor",
+   "file": "modules/core/module-debug-supervisor.js",
+   "tier": "core-bundle",
+   "category": "general",
+   "desc": "feedback-admin — command from module-debug-supervisor",
+   "builtin": false,
+   "example": "feedback-admin"
+  },
+  "feedback-inbox": {
+   "module": "module-debug-supervisor",
+   "file": "modules/core/module-debug-supervisor.js",
+   "tier": "core-bundle",
+   "category": "general",
+   "desc": "feedback-inbox — Read replies from the maintenance agent (admin session)",
+   "builtin": false,
+   "example": "feedback-inbox"
+  },
   "fetch": {
    "module": "module-fetcher",
    "file": "modules/core/module-fetcher.js",
@@ -1118,6 +1154,15 @@
    "builtin": false,
    "example": "gui-text"
   },
+  "guides": {
+   "module": "module-fs",
+   "file": "modules/core/module-fs.js",
+   "tier": "core-bundle",
+   "category": "filesystem",
+   "desc": "Use trash for recursive dir removal too",
+   "builtin": false,
+   "example": "guides"
+  },
   "gunzip": {
    "module": "cryptogzip",
    "file": "modules/ext/cryptogzip.js",
@@ -1163,6 +1208,33 @@
    "builtin": false,
    "example": "help"
   },
+  "hermes": {
+   "module": "module-debug-supervisor",
+   "file": "modules/core/module-debug-supervisor.js",
+   "tier": "core-bundle",
+   "category": "general",
+   "desc": "hermes — command from module-debug-supervisor",
+   "builtin": false,
+   "example": "hermes"
+  },
+  "hermes-poll": {
+   "module": "module-debug-supervisor",
+   "file": "modules/core/module-debug-supervisor.js",
+   "tier": "core-bundle",
+   "category": "general",
+   "desc": "hermes-poll — command from module-debug-supervisor",
+   "builtin": false,
+   "example": "hermes-poll"
+  },
+  "hermes-reset": {
+   "module": "module-debug-supervisor",
+   "file": "modules/core/module-debug-supervisor.js",
+   "tier": "core-bundle",
+   "category": "general",
+   "desc": "hermes-reset — command from module-debug-supervisor",
+   "builtin": false,
+   "example": "hermes-reset"
+  },
   "history": {
    "module": "terminal",
    "file": "modules/core/terminal.js",
@@ -1942,7 +2014,7 @@
    "file": "modules/core/module-predictor.js",
    "tier": "core-bundle",
    "category": "general",
-   "desc": "predictor-config <key> <value> — Tune: confidence-threshold, min-data-points",
+   "desc": "predictor-config <key> <value> — Tune: confidence-threshold, min-data-points, pair-ttl",
    "builtin": false,
    "example": "predictor-config"
   },
@@ -1951,7 +2023,7 @@
    "file": "modules/core/module-predictor.js",
    "tier": "core-bundle",
    "category": "general",
-   "desc": "predictor-status — Model accuracy, data points, prediction count",
+   "desc": "predictor-status — Paired accuracy, pending predictions, data points",
    "builtin": false,
    "example": "predictor-status"
   },
@@ -2419,7 +2491,7 @@
    "file": "modules/ext/skill-pack-core.js",
    "tier": "ext-auto",
    "category": "ai",
-   "desc": "skill-create <name> <desc> \"<steps>\" [tags] — Create a new skill",
+   "desc": "skill-create <name> <desc> <path-or-text> [--tags=a,b] [--category=x] — Create a new skill",
    "builtin": false,
    "example": "skill-create"
   },
@@ -2621,6 +2693,15 @@
    "builtin": false,
    "example": "tar"
   },
+  "test": {
+   "module": "shell",
+   "file": "modules/ext/shell.js",
+   "tier": "critical-ext-bundle",
+   "category": "shell",
+   "desc": "32 automated tests: filesystem, busybox, shell, cryptogzip, skills, security, modules. Load manually with load-local then test",
+   "builtin": false,
+   "example": "test"
+  },
   "test-net": {
    "module": "module-servermon",
    "file": "modules/core/module-servermon.js",
@@ -2748,12 +2829,12 @@
    "example": "uptime"
   },
   "usage": {
-   "module": "terminal",
-   "file": "modules/core/terminal.js",
+   "module": "module-billing",
+   "file": "modules/core/module-billing.js",
    "tier": "core-bundle",
-   "category": "system",
-   "desc": "usage — command from terminal",
-   "builtin": true,
+   "category": "general",
+   "desc": "usage — same as cost",
+   "builtin": false,
    "example": "usage"
   },
   "vaultmind-connect": {
@@ -3166,7 +3247,7 @@
     "js-run",
     "node"
    ],
-   "lines": 96
+   "lines": 139
   },
   "course": {
    "file": "modules/ext/course.js",
@@ -3232,7 +3313,7 @@
     "files",
     "preview"
    ],
-   "lines": 1151
+   "lines": 1278
   },
   "finder": {
    "file": "modules/ext/finder.js",
@@ -3296,7 +3377,7 @@
     "contract-list",
     "contract-register"
    ],
-   "lines": 474
+   "lines": 506
   },
   "module-aiasm": {
    "file": "modules/core/module-aiasm.js",
@@ -3350,7 +3431,16 @@
     "vaultmind-status",
     "wallet-lookup"
    ],
-   "lines": 4678
+   "lines": 4934
+  },
+  "module-billing": {
+   "file": "modules/core/module-billing.js",
+   "tier": "core-bundle",
+   "commands": [
+    "cost",
+    "usage"
+   ],
+   "lines": 185
   },
   "module-chatstudio": {
    "file": "modules/core/module-chatstudio.js",
@@ -3384,9 +3474,15 @@
     "debug-stats",
     "debug-sync",
     "debug-sync-url",
-    "debug-trends"
+    "debug-trends",
+    "feedback",
+    "feedback-admin",
+    "feedback-inbox",
+    "hermes",
+    "hermes-poll",
+    "hermes-reset"
    ],
-   "lines": 890
+   "lines": 1228
   },
   "module-fetcher": {
    "file": "modules/core/module-fetcher.js",
@@ -3410,6 +3506,7 @@
     "empty-trash",
     "find",
     "grep",
+    "guides",
     "head",
     "ls",
     "ls-trash",
@@ -3439,7 +3536,7 @@
     "vfs-size",
     "wc"
    ],
-   "lines": 823
+   "lines": 982
   },
   "module-leases": {
    "file": "modules/core/module-leases.js",
@@ -3466,7 +3563,7 @@
     "memgraph-stats",
     "memgraph-status"
    ],
-   "lines": 663
+   "lines": 703
   },
   "module-modmgr": {
    "file": "modules/core/module-modmgr.js",
@@ -3553,7 +3650,7 @@
     "orchestrator-wake",
     "pipeline"
    ],
-   "lines": 1442
+   "lines": 1485
   },
   "module-predictor": {
    "file": "modules/core/module-predictor.js",
@@ -3563,7 +3660,7 @@
     "predictor-config",
     "predictor-status"
    ],
-   "lines": 282
+   "lines": 509
   },
   "module-sandbox": {
    "file": "modules/core/module-sandbox.js",
@@ -3656,7 +3753,7 @@
     "uptime",
     "version"
    ],
-   "lines": 815
+   "lines": 834
   },
   "module-world-model": {
    "file": "modules/core/module-world-model.js",
@@ -3668,7 +3765,7 @@
     "world-model-refresh",
     "world-model-summary"
    ],
-   "lines": 600
+   "lines": 647
   },
   "secret-vault": {
    "file": "modules/core/secret-vault.js",
@@ -3693,9 +3790,10 @@
     "script",
     "set",
     "sh",
+    "test",
     "unset"
    ],
-   "lines": 627
+   "lines": 956
   },
   "skill-pack-core": {
    "file": "modules/ext/skill-pack-core.js",
@@ -3716,7 +3814,7 @@
     "skill-view",
     "skill-webdav-sync"
    ],
-   "lines": 1150
+   "lines": 1334
   },
   "theme": {
    "file": "modules/ext/theme.js",
@@ -3770,7 +3868,7 @@
     "webdav-rm",
     "webdav-status"
    ],
-   "lines": 2368
+   "lines": 2450
   },
   "wpm": {
    "file": "modules/ext/wpm.js",
@@ -3782,12 +3880,12 @@
   }
  },
  "coverage": {
-  "commands": 346,
-  "described": 346,
-  "modules": 47,
+  "commands": 355,
+  "described": 355,
+  "modules": 48,
   "tiers": {
-   "core-bundle": 258,
-   "critical-ext-bundle": 28,
+   "core-bundle": 266,
+   "critical-ext-bundle": 29,
    "ext-auto": 60,
    "ext-manual": 0
   }
diff --git a/help.html b/help.html
index 33c6601..b2caf27 100644
--- a/help.html
+++ b/help.html
@@ -525,6 +525,7 @@ diff a.txt b.txt</pre>
       <tr><td><code>checkpoint-del</code></td><td>Delete a checkpoint</td><td><code>checkpoint-del</code></td></tr>
       <tr><td><code>smart-prompt</code></td><td>Toggle context-aware prompt</td><td><code>smart-prompt</code></td></tr>
       <tr><td><code>test</code></td><td>Run test suite</td><td><code>test auto</code></td></tr>
+      <tr><td><code>[ … ]</code> / <code>test …</code></td><td>POSIX file and string test for chains — silent, combines with <code>&amp;&amp;</code> / <code>||</code>. Operators: <code>-f</code> <code>-d</code> <code>-e</code> <code>-z</code> <code>-n</code> <code>!</code> <code>=</code> <code>!=</code>. The expression form of <code>test</code> is routed to this; <code>test</code> with no expression still runs the suite.</td><td><code>[ -f /notes.txt ] &amp;&amp; echo yes</code></td></tr>
     </table></div>
 
     <h3>AI Assistant</h3>
diff --git a/main.html b/main.html
index 66c1d76..6b1aed4 100644
--- a/main.html
+++ b/main.html
@@ -1349,13 +1349,13 @@
     </script>
 
     <!-- v4.5.63: A2A scratchpad fixes + agent-register arg fix -->
-<script src="modules/core/core-bundle.js?v=v4.6.132"></script>
+<script src="modules/core/core-bundle.js?v=v4.6.135"></script>
 
     <!-- Async dependency-ordered module loader now only initializes terminal and loads optional ext modules -->
-<script src="modules/core/module-loader.js?v=v4.6.132"></script>
+<script src="modules/core/module-loader.js?v=v4.6.135"></script>
 
     <!-- Critical ext bundle loads AFTER webx11 exists so registerModule calls work -->
-<script src="modules/ext/critical-ext-bundle.js?v=v4.6.132"></script>
+<script src="modules/ext/critical-ext-bundle.js?v=v4.6.135"></script>
 
 <script>
 // ═══ ONE TRUE VERSION SOURCE ═══
diff --git a/modules/core/core-bundle.js b/modules/core/core-bundle.js
index b070e65..07609e3 100644
--- a/modules/core/core-bundle.js
+++ b/modules/core/core-bundle.js
@@ -4553,6 +4553,9 @@ Only output XML function calls for tool tasks. If no tool is needed, answer norm
                               }
                               return; }
                         catch (err) {
+                            // v4.6.134: `silent` errors are control flow, not failures — `test`/`[`
+                            // reject to tell `&&`/`||` to skip, and must print nothing (POSIX).
+                            if (err && err.silent) return;
                             this.print(`Error in ${modName}.${cmd}: ${err.message}`, 'error');
                             console.error(`[Terminal] Error in ${modName}.${cmd}:`, err);
                             return;
diff --git a/modules/core/module-loader.js b/modules/core/module-loader.js
index 0d39123..52cee36 100644
--- a/modules/core/module-loader.js
+++ b/modules/core/module-loader.js
@@ -4,7 +4,7 @@
     // Core module bundle loaded synchronously in main.html.
     // This loader only handles version cache-busting, splash, terminal init, and optional ext modules.
 
-    const LATEST_VER = 'v4.6.132';
+    const LATEST_VER = 'v4.6.135';
     const CACHE = '?v=' + LATEST_VER;
     // Exposed so ext modules can register their own URL with the same cache-busting version
     // instead of an unversioned path the browser may already have cached (shell.js did).
diff --git a/modules/core/terminal.js b/modules/core/terminal.js
index 4122b3c..ca6bb61 100644
--- a/modules/core/terminal.js
+++ b/modules/core/terminal.js
@@ -1961,6 +1961,9 @@
                               }
                               return; }
                         catch (err) {
+                            // v4.6.134: `silent` errors are control flow, not failures — `test`/`[`
+                            // reject to tell `&&`/`||` to skip, and must print nothing (POSIX).
+                            if (err && err.silent) return;
                             this.print(`Error in ${modName}.${cmd}: ${err.message}`, 'error');
                             console.error(`[Terminal] Error in ${modName}.${cmd}:`, err);
                             return;
diff --git a/modules/ext/critical-ext-bundle.js b/modules/ext/critical-ext-bundle.js
index 0f2e1b9..53f1205 100644
--- a/modules/ext/critical-ext-bundle.js
+++ b/modules/ext/critical-ext-bundle.js
@@ -170,6 +170,46 @@ class ShellModule {
         this.commands['script'] = (args) => this._cmdScript(args);
         this.commands['sh'] = (args) => this._cmdScript(args);
         this.commands['set'] = () => this._cmdSet();
+        // v4.6.133: `test` / `[` were not registered, so `[ -f /x ] && echo yes` fell through to the
+        // AI fallback and asked a model whether a file exists. _evalTest() already implemented the
+        // operators (-f -d -e -z -n ! = !=) for the if/while parser; the command was simply missing.
+        // `test` already means "run the regression suite" in the on-demand test-suite module, so a
+        // non-expression argument list is delegated to whatever handler was registered before us.
+        const prevTest = this.commands['test'];
+        this.commands['test'] = (args) => this._cmdTest(args, 'test', prevTest);
+        this.commands['['] = (args) => this._cmdTest(args, '[');
+    }
+
+    /** True when the argv looks like a POSIX test expression rather than a suite-runner subcommand. */
+    _looksLikeTest(expr) {
+        if (!expr) return false;
+        if (/^(?:!(?:\s|$)|-[fderwxszn]\b)/.test(expr)) return true;      // `-f x`, `! -d y`
+        if (/\s(?:=|==|!=)\s/.test(expr)) return true;                    // `a = b`
+        return false;
+    }
+
+    /** POSIX-ish `test`/`[`: silent on success, throws a silent error on false so `&&`/`||` skip. */
+    _cmdTest(args, name, fallback) {
+        let expr = (args || []).join(' ').trim();
+        if (name === 'test' && !this._looksLikeTest(expr) && typeof fallback === 'function') {
+            return fallback(args);          // `test`, `test auto`, `test list` -> the suite runner
+        }
+        if (name === '[') {
+            if (!expr.endsWith(']')) throw new Error("[ : missing ']'");
+            expr = expr.slice(0, -1).trim();
+        }
+        if (!expr) {                       // `test` with no expression: false, and no output
+            const e = new Error(''); e.silent = true; throw e;
+        }
+        if (!this._evalTest(expr)) {
+            const e = new Error(''); e.silent = true; throw e;   // POSIX: exit 1 prints nothing
+        }
+    }
+
+    /** Error printer shared by the shell paths: `silent` errors are control flow (a false test), not failures. */
+    _printErr(term, e) {
+        if (!e || e.silent) return;
+        (term || this.terminal).print('Error: ' + (e.message || e), 'error');
     }
 
     // ── Hook into terminal.executeCommand ──
@@ -259,7 +299,7 @@ class ShellModule {
                                     await self.commands[cmd](args);
                                     lastOk = true;
                                 } catch(e) {
-                                    this.print('Error: ' + e.message, 'error');
+                                    self._printErr(this, e);
                                     lastOk = false;
                                 }
                             } else {
@@ -267,7 +307,7 @@ class ShellModule {
                                     await this.security.checkAndRun(expandedCmd);
                                     lastOk = true;
                                 } catch(e) {
-                                    this.print('Error: ' + e.message, 'error');
+                                    self._printErr(this, e);
                                     lastOk = false;
                                 }
                             }
diff --git a/modules/ext/shell.js b/modules/ext/shell.js
index cb26484..ff07d92 100644
--- a/modules/ext/shell.js
+++ b/modules/ext/shell.js
@@ -34,6 +34,46 @@ class ShellModule {
         this.commands['script'] = (args) => this._cmdScript(args);
         this.commands['sh'] = (args) => this._cmdScript(args);
         this.commands['set'] = () => this._cmdSet();
+        // v4.6.133: `test` / `[` were not registered, so `[ -f /x ] && echo yes` fell through to the
+        // AI fallback and asked a model whether a file exists. _evalTest() already implemented the
+        // operators (-f -d -e -z -n ! = !=) for the if/while parser; the command was simply missing.
+        // `test` already means "run the regression suite" in the on-demand test-suite module, so a
+        // non-expression argument list is delegated to whatever handler was registered before us.
+        const prevTest = this.commands['test'];
+        this.commands['test'] = (args) => this._cmdTest(args, 'test', prevTest);
+        this.commands['['] = (args) => this._cmdTest(args, '[');
+    }
+
+    /** True when the argv looks like a POSIX test expression rather than a suite-runner subcommand. */
+    _looksLikeTest(expr) {
+        if (!expr) return false;
+        if (/^(?:!(?:\s|$)|-[fderwxszn]\b)/.test(expr)) return true;      // `-f x`, `! -d y`
+        if (/\s(?:=|==|!=)\s/.test(expr)) return true;                    // `a = b`
+        return false;
+    }
+
+    /** POSIX-ish `test`/`[`: silent on success, throws a silent error on false so `&&`/`||` skip. */
+    _cmdTest(args, name, fallback) {
+        let expr = (args || []).join(' ').trim();
+        if (name === 'test' && !this._looksLikeTest(expr) && typeof fallback === 'function') {
+            return fallback(args);          // `test`, `test auto`, `test list` -> the suite runner
+        }
+        if (name === '[') {
+            if (!expr.endsWith(']')) throw new Error("[ : missing ']'");
+            expr = expr.slice(0, -1).trim();
+        }
+        if (!expr) {                       // `test` with no expression: false, and no output
+            const e = new Error(''); e.silent = true; throw e;
+        }
+        if (!this._evalTest(expr)) {
+            const e = new Error(''); e.silent = true; throw e;   // POSIX: exit 1 prints nothing
+        }
+    }
+
+    /** Error printer shared by the shell paths: `silent` errors are control flow (a false test), not failures. */
+    _printErr(term, e) {
+        if (!e || e.silent) return;
+        (term || this.terminal).print('Error: ' + (e.message || e), 'error');
     }
 
     // ── Hook into terminal.executeCommand ──
@@ -123,7 +163,7 @@ class ShellModule {
                                     await self.commands[cmd](args);
                                     lastOk = true;
                                 } catch(e) {
-                                    this.print('Error: ' + e.message, 'error');
+                                    self._printErr(this, e);
                                     lastOk = false;
                                 }
                             } else {
@@ -131,7 +171,7 @@ class ShellModule {
                                     await this.security.checkAndRun(expandedCmd);
                                     lastOk = true;
                                 } catch(e) {
-                                    this.print('Error: ' + e.message, 'error');
+                                    self._printErr(this, e);
                                     lastOk = false;
                                 }
                             }
diff --git a/modules/test/test-shell-test-cmd.js b/modules/test/test-shell-test-cmd.js
new file mode 100644
index 0000000..6abdd11
--- /dev/null
+++ b/modules/test/test-shell-test-cmd.js
@@ -0,0 +1,98 @@
+// node modules/test/test-shell-test-cmd.js
+//
+// `test` / `[` were not registered, so `[ -f /x ] && echo yes` fell through to the AI fallback and
+// asked a model whether a file exists (measured 2026-10-29 on v4.6.132). _evalTest() already had the
+// operators; the command was missing. Contract pinned here:
+//   success -> resolves silently
+//   false   -> rejects with a `silent` error (so `&&`/`||` skip without printing "Error: ")
+//   `[`     -> requires the closing bracket, never delegates
+//   `test`  -> a non-POSIX argv still reaches the regression-suite runner registered before it
+const fs = require('fs'), path = require('path');
+// shell.js ends with `if (typeof window.webx11 !== 'undefined' && window.webx11) { … }` — and
+// `typeof window.webx11` throws when `window` itself is undeclared, so give it an empty object.
+global.window = {};
+const src = fs.readFileSync(path.join(__dirname, '../ext/shell.js'), 'utf8');
+const ShellModule = new Function(src + '\n;return typeof ShellModule !== "undefined" ? ShellModule : null;')();
+
+let pass = 0, fail = 0;
+const ok = (name, cond, detail) => { cond ? pass++ : (fail++, console.log('FAIL ' + name + (detail ? ' — ' + detail : ''))); };
+const eq = (name, got, want) => ok(name, JSON.stringify(got) === JSON.stringify(want), 'got ' + JSON.stringify(got) + ' want ' + JSON.stringify(want));
+
+function mk(filesArg) {
+    const printed = [];
+    const files = filesArg || { '/a.txt': 'x', '/dir': null };   // null => directory
+    const term = {
+        print: (m, lvl) => printed.push({ m: String(m), lvl: lvl || 'plain' }),
+        markDirty: () => {},
+        fs: {
+            currentPath: [],
+            readFile: p => (typeof files[p] === 'string' ? files[p] : null),
+            readDir: p => (p in files && files[p] === null ? [] : null)
+        },
+        // A real (simple) parser: the assertions prove _tokenize delegates by counting the calls.
+        security: { calls: 0, _parseArgs: function (s) { this.calls++; return s.trim() ? s.trim().split(/\s+/) : []; } }
+    };
+    const m = new ShellModule();
+    m.terminal = term;
+    m.registerCommands();
+    return { m, term, printed };
+}
+
+const throws = async (fn) => { try { await fn(); return null; } catch (e) { return e; } };
+
+(async () => {
+    const { m, term, printed } = mk();
+
+    ok('test command registered', typeof m.commands['test'] === 'function');
+    ok('[ command registered', typeof m.commands['['] === 'function');
+
+    ok('test -f existing file -> resolves', await throws(() => m.commands['test'](['-f', '/a.txt'])) === null);
+
+    const missing = await throws(() => m.commands['test'](['-f', '/nope']));
+    ok('test -f missing file -> rejects', !!missing);
+    ok('rejection is silent', !!missing && missing.silent === true, 'silent=' + (missing && missing.silent));
+    ok('rejection carries no message', !!missing && !missing.message, 'msg=' + JSON.stringify(missing && missing.message));
+
+    ok('[ -f /a.txt ] -> resolves', await throws(() => m.commands['['](['-f', '/a.txt', ']'])) === null);
+
+    const noBracket = await throws(() => m.commands['['](['-f', '/a.txt']));
+    ok('[ without ] -> rejects', !!noBracket && /missing '\]'/.test(noBracket.message), noBracket && noBracket.message);
+    ok('[ without ] is NOT silent (a syntax error must be visible)', !!noBracket && !noBracket.silent);
+
+    ok('test -d dir -> resolves', await throws(() => m.commands['test'](['-d', '/dir'])) === null);
+    ok('test -d file -> rejects', !!(await throws(() => m.commands['test'](['-d', '/a.txt']))));
+
+    const noExpr = await throws(() => m.commands['test']([]));
+    ok('test with no fallback and no args -> silent reject (POSIX false)', !!noExpr && noExpr.silent === true);
+
+    // shared printer: silent errors print nothing, real ones print "Error: …"
+    printed.length = 0;
+    m._printErr(term, Object.assign(new Error(''), { silent: true }));
+    ok('_printErr swallows silent errors', printed.length === 0, JSON.stringify(printed));
+    m._printErr(term, new Error('boom'));
+    eq('_printErr prints real errors', printed, [{ m: 'Error: boom', lvl: 'error' }]);
+
+    // _tokenize must delegate to the security parser, never to split(/\s+/) of its own
+    const before = term.security.calls;
+    eq('_tokenize delegates to security._parseArgs', m._tokenize('anything at all'), ['anything', 'at', 'all']);
+    ok('_tokenize actually called the parser', term.security.calls > before, 'calls=' + term.security.calls);
+    eq('_tokenize empty -> []', m._tokenize('   '), []);
+    eq('_tokenize undefined -> []', m._tokenize(undefined), []);
+
+    // `test` also names the on-demand regression-suite runner ("test auto" / "test list").
+    const { m: d } = mk();
+    const seen = [];
+    const prev = d.commands['test'];
+    d.commands['test'] = (args) => d._cmdTest(args, 'test', (a) => { seen.push(a); return 'suite'; });
+    ok('previous handler is what delegation falls back to', typeof prev === 'function');
+
+    ok('test auto delegates to the suite runner', (await d.commands['test'](['auto'])) === 'suite' && JSON.stringify(seen) === '[["auto"]]', JSON.stringify(seen));
+    ok('bare test delegates to the suite runner', (await d.commands['test']([])) === 'suite' && seen.length === 2, JSON.stringify(seen));
+    ok('test -f still runs POSIX (no delegation)', (await throws(() => d.commands['test'](['-f', '/a.txt']))) === null && seen.length === 2, 'seen=' + JSON.stringify(seen));
+    ok('string equality form runs POSIX', (await throws(() => d.commands['test'](['/a.txt', '=', '/a.txt']))) === null && seen.length === 2, 'seen=' + JSON.stringify(seen));
+    const t2 = await throws(() => d.commands['['](['-f', '/nope', ']']));
+    ok('[ never delegates', !!t2 && t2.silent === true, JSON.stringify(seen));
+
+    console.log(pass + '/' + (pass + fail) + ' pass');
+    process.exit(fail ? 1 : 0);
+})();