test: add unit tests for roster loading logic

- Implemented dependency injection in `src/roster.mjs` to allow mocking `fs` and `loadTorchConfig`.
- Added `test/roster.test.mjs` with comprehensive test cases:
    - Fallback behavior when no files/config exist.
    - Priority of `torch/roster.json` (User Roster) over `roster.json` (CWD).
    - Internal module roster fallback.
    - Environment variable overrides.
    - Configuration overrides.
    - Error handling for malformed JSON or missing fields.
- Exported `_resetRosterCache`, `_setRosterDependencies`, and `_restoreRosterDependencies` for testing purposes.

Co-authored-by: PR0M3TH3AN <[email protected]>

src/roster.mjs

@@ -3,6 +3,23 @@ import path from 'node:path';
 import { fileURLToPath } from 'node:url';
 import { loadTorchConfig } from './torch-config.mjs';
 
+const defaultDeps = {
+  fs,
+  loadTorchConfig,
+};
+
+const deps = { ...defaultDeps };
+
+/** @internal */
+export function _setRosterDependencies(overrides) {
+  Object.assign(deps, overrides);
+}
+
+/** @internal */
+export function _restoreRosterDependencies() {
+  Object.assign(deps, defaultDeps);
+}
+
 const ROSTER_FILE = path.resolve(path.dirname(fileURLToPath(import.meta.url)), 'prompts/roster.json');
 const USER_ROSTER_FILE = path.resolve(process.cwd(), 'torch/roster.json');
 const CWD_ROSTER_FILE = path.resolve(process.cwd(), 'roster.json');
@@ -59,14 +76,14 @@ function loadCanonicalRoster() {
   let rosterPath = ROSTER_FILE;
 
   // Prefer user-managed roster if present
-  if (fs.existsSync(USER_ROSTER_FILE)) {
+  if (deps.fs.existsSync(USER_ROSTER_FILE)) {
     rosterPath = USER_ROSTER_FILE;
-  } else if (fs.existsSync(CWD_ROSTER_FILE)) {
+  } else if (deps.fs.existsSync(CWD_ROSTER_FILE)) {
     rosterPath = CWD_ROSTER_FILE;
   }
 
   try {
-    const parsed = JSON.parse(fs.readFileSync(rosterPath, 'utf8'));
+    const parsed = JSON.parse(deps.fs.readFileSync(rosterPath, 'utf8'));
     const daily = Array.isArray(parsed.daily) ? parsed.daily.map((item) => String(item).trim()).filter(Boolean) : [];
     const weekly = Array.isArray(parsed.weekly)
       ? parsed.weekly.map((item) => String(item).trim()).filter(Boolean)
@@ -86,6 +103,11 @@ function loadCanonicalRoster() {
   return cachedCanonicalRoster;
 }
 
+/** @internal */
+export function _resetRosterCache() {
+  cachedCanonicalRoster = null;
+}
+
 function parseEnvRoster(value) {
   if (!value) return null;
   return value
@@ -95,7 +117,7 @@ function parseEnvRoster(value) {
 }
 
 export async function getRoster(cadence) {
-  const config = await loadTorchConfig();
+  const config = await deps.loadTorchConfig();
   const dailyFromEnv = parseEnvRoster(process.env.NOSTR_LOCK_DAILY_ROSTER);
   const weeklyFromEnv = parseEnvRoster(process.env.NOSTR_LOCK_WEEKLY_ROSTER);
   const canonical = loadCanonicalRoster();