[server/logging] add tests for log interceptor

src/server/logging/__tests__/log_interceptor.js

@@ -0,0 +1,55 @@
+import expect from 'expect.js';
+import { shuffle } from 'lodash';
+
+import { LogInterceptor } from '../log_interceptor';
+
+function stubEconnresetEvent() {
+  const error = new Error();
+  error.errno = 'ECONNRESET';
+
+  return {
+    event: 'error',
+    pid: 1234,
+    timestamp: Date.now(),
+    tags: ['error', 'client', 'connection'],
+    data: error
+  };
+}
+
+function assertDowngraded(transformed) {
+  expect(!!transformed).to.be(true);
+  expect(transformed).to.have.property('event', 'log');
+  expect(transformed).to.have.property('tags');
+  expect(transformed.tags).to.not.contain('error');
+}
+
+describe('server logging LogInterceptor', () => {
+  describe('#downgradeIfEconnreset()', () => {
+    it('transforms ECONNRESET events', () => {
+      const interceptor = new LogInterceptor();
+      const event = stubEconnresetEvent();
+      assertDowngraded(interceptor.downgradeIfEconnreset(event));
+    });
+
+    it('matches even when the tags are out of order', () => {
+      const interceptor = new LogInterceptor();
+      const event = stubEconnresetEvent();
+      event.tags = shuffle(event.tags.slice(0));
+      assertDowngraded(interceptor.downgradeIfEconnreset(event));
+    });
+
+    it('ignores non ECONNRESET events', () => {
+      const interceptor = new LogInterceptor();
+      const event = stubEconnresetEvent();
+      event.data.errno = 'not ECONNRESET';
+      expect(interceptor.downgradeIfEconnreset(event)).to.be(null);
+    });
+
+    it('ignores if tags are wrong', () => {
+      const interceptor = new LogInterceptor();
+      const event = stubEconnresetEvent();
+      event.tags = ['different', 'tags'];
+      expect(interceptor.downgradeIfEconnreset(event)).to.be(null);
+    });
+  });
+});

src/server/logging/log_interceptor.js

@@ -27,7 +27,7 @@ export class LogInterceptor extends Stream.Transform {
     const isClientError = doTagsMatch(event, ['error', 'client', 'connection']);
     const isEconnreset = isClientError && get(event, 'data.errno') === 'ECONNRESET';
 
-    if (!isEconnreset) return false;
+    if (!isEconnreset) return null;
 
     return {
       event: 'log',