feat(crash): add CrashWriter for local crash dumps (cap 20, prune oldest)

tests/unit/main/updater/crash-writer.test.js

@@ -0,0 +1,56 @@
+const fs = require('fs');
+const path = require('path');
+const os = require('os');
+const { CrashWriter } = require('../../../../src/main/updater/crash-writer');
+
+function tmpDir() {
+  return fs.mkdtempSync(path.join(os.tmpdir(), 'crash-test-'));
+}
+
+describe('CrashWriter', () => {
+  test('writes a JSON dump for an uncaught exception', () => {
+    const dir = tmpDir();
+    const writer = new CrashWriter(dir);
+    const err = new Error('boom');
+    err.stack = 'Error: boom\n  at test.js:1:1';
+    writer.handleUncaught(err, 'uncaughtException');
+    const files = fs.readdirSync(dir);
+    expect(files.length).toBe(1);
+    const data = JSON.parse(fs.readFileSync(path.join(dir, files[0]), 'utf-8'));
+    expect(data.kind).toBe('uncaughtException');
+    expect(data.message).toBe('boom');
+    expect(data.stack).toContain('test.js:1:1');
+    fs.rmSync(dir, { recursive: true });
+  });
+
+  test('caps at 20 dumps, pruning oldest', () => {
+    const dir = tmpDir();
+    const writer = new CrashWriter(dir);
+    for (let i = 0; i < 25; i++) {
+      writer.handleUncaught(new Error(`e${i}`), 'unhandledRejection');
+    }
+    const files = fs.readdirSync(dir);
+    expect(files.length).toBe(20);
+    fs.rmSync(dir, { recursive: true });
+  });
+
+  test('returns the list of dumps', () => {
+    const dir = tmpDir();
+    const writer = new CrashWriter(dir);
+    writer.handleUncaught(new Error('a'), 'uncaughtException');
+    writer.handleUncaught(new Error('b'), 'uncaughtException');
+    const list = writer.list();
+    expect(list.length).toBe(2);
+    fs.rmSync(dir, { recursive: true });
+  });
+
+  test('deletes a dump by filename', () => {
+    const dir = tmpDir();
+    const writer = new CrashWriter(dir);
+    writer.handleUncaught(new Error('x'), 'uncaughtException');
+    const list = writer.list();
+    writer.delete(list[0].filename);
+    expect(writer.list().length).toBe(0);
+    fs.rmSync(dir, { recursive: true });
+  });
+});