test(node): Add memory leak test for LocalVariables (#10080)

This PR adds a test for the `LocalVariable` integration that causes 20k
caught exceptions and checks that the memory usage does not go over
100MB.

Author: timfish

dev-packages/node-integration-tests/suites/public-api/LocalVariables/local-variables-memory-test.js

@@ -0,0 +1,44 @@
+/* eslint-disable no-unused-vars */
+const Sentry = require('@sentry/node');
+
+Sentry.init({
+  dsn: 'https://[email protected]/1337',
+  includeLocalVariables: true,
+  beforeSend: _ => {
+    return null;
+  },
+  // Stop the rate limiting from kicking in
+  integrations: [new Sentry.Integrations.LocalVariables({ maxExceptionsPerSecond: 10000000 })],
+});
+
+class Some {
+  two(name) {
+    throw new Error('Enough!');
+  }
+}
+
+function one(name) {
+  const arr = [1, '2', null];
+  const obj = {
+    name,
+    num: 5,
+  };
+
+  const ty = new Some();
+
+  ty.two(name);
+}
+
+// Every millisecond cause a caught exception
+setInterval(() => {
+  try {
+    one('some name');
+  } catch (e) {
+    //
+  }
+}, 1);
+
+// Every second send a memory usage update to parent process
+setInterval(() => {
+  process.send({ memUsage: process.memoryUsage() });
+}, 1000);

dev-packages/node-integration-tests/suites/public-api/LocalVariables/test.ts

@@ -109,4 +109,29 @@ conditionalTest({ min: 18 })('LocalVariables integration', () => {
       done();
     });
   });
+
+  test('Should not leak memory', done => {
+    const testScriptPath = path.resolve(__dirname, 'local-variables-memory-test.js');
+
+    const child = childProcess.spawn('node', [testScriptPath], {
+      stdio: ['inherit', 'inherit', 'inherit', 'ipc'],
+    });
+
+    let reportedCount = 0;
+
+    child.on('message', msg => {
+      reportedCount++;
+      const rssMb = msg.memUsage.rss / 1024 / 1024;
+      // We shouldn't use more than 100MB of memory
+      expect(rssMb).toBeLessThan(100);
+    });
+
+    // Wait for 20 seconds
+    setTimeout(() => {
+      // Ensure we've had memory usage reported at least 15 times
+      expect(reportedCount).toBeGreaterThan(15);
+      child.kill();
+      done();
+    }, 20000);
+  });
 });