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Module

std/log/file_handler_test.ts

Deno standard library
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// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.import { assertEquals, assertThrows } from "../assert/mod.ts";import { LogLevels } from "./levels.ts";import { FileHandler } from "./file_handler.ts";import { LogRecord } from "./logger.ts";
const LOG_FILE = "./file_handler_test_log.file";
Deno.test({ name: "FileHandler doesn't have broken line", fn() { class TestFileHandler extends FileHandler { override flush() { super.flush(); const decoder = new TextDecoder("utf-8"); const data = Deno.readFileSync(LOG_FILE); const text = decoder.decode(data); assertEquals(text.slice(-1), "\n"); }
override destroy() { super.destroy(); Deno.removeSync(LOG_FILE); } }
using testFileHandler = new TestFileHandler("WARN", { filename: LOG_FILE, mode: "w", }); testFileHandler.setup();
for (let i = 0; i < 300; i++) { testFileHandler.handle( new LogRecord({ msg: "The starry heavens above me and the moral law within me.", args: [], level: LogLevels.WARN, loggerName: "default", }), ); } },});
Deno.test({ name: "FileHandler wipes existing log file clean with mode 'w'", async fn() { const fileHandler = new FileHandler("WARN", { filename: LOG_FILE, mode: "w", });
fileHandler.setup(); fileHandler.handle( new LogRecord({ msg: "Hello World", args: [], level: LogLevels.WARN, loggerName: "default", }), ); fileHandler.destroy(); const firstFileSize = (await Deno.stat(LOG_FILE)).size;
fileHandler.setup(); fileHandler.handle( new LogRecord({ msg: "Hello World", args: [], level: LogLevels.WARN, loggerName: "default", }), ); fileHandler.destroy(); const secondFileSize = (await Deno.stat(LOG_FILE)).size;
assertEquals(secondFileSize, firstFileSize); Deno.removeSync(LOG_FILE); },});
Deno.test({ name: "FileHandler throws if log file already exists with mode 'x'", fn() { using fileHandler = new FileHandler("WARN", { filename: LOG_FILE, mode: "x", }); Deno.writeFileSync(LOG_FILE, new TextEncoder().encode("hello world"));
assertThrows(() => { fileHandler.setup(); }, Deno.errors.AlreadyExists);
Deno.removeSync(LOG_FILE); },});
Deno.test({ name: "FileHandler flushes buffer on unload", async fn() { const fileHandler = new FileHandler("WARN", { filename: LOG_FILE, mode: "w", }); fileHandler.setup(); fileHandler.handle( new LogRecord({ msg: "AAA", args: [], level: LogLevels.ERROR, loggerName: "default", }), ); // 'ERROR AAA\n' = 10 bytes
assertEquals((await Deno.stat(LOG_FILE)).size, 0); dispatchEvent(new Event("unload")); dispatchEvent(new Event("unload")); assertEquals((await Deno.stat(LOG_FILE)).size, 10);
Deno.removeSync(LOG_FILE); },});
Deno.test({ name: "FileHandler triggers immediate flush on critical logs", async fn() { using fileHandler = new FileHandler("WARN", { filename: LOG_FILE, mode: "w", }); fileHandler.setup();
fileHandler.handle( new LogRecord({ msg: "AAA", args: [], level: LogLevels.ERROR, loggerName: "default", }), );
// ERROR won't trigger immediate flush const fileSize = (await Deno.stat(LOG_FILE)).size; assertEquals(fileSize, 0);
fileHandler.handle( new LogRecord({ msg: "AAA", args: [], level: LogLevels.CRITICAL, loggerName: "default", }), );
// CRITICAL will trigger immediate flush const fileSize2 = (await Deno.stat(LOG_FILE)).size; // ERROR record is 10 bytes, CRITICAL is 13 bytes assertEquals(fileSize2, 23);
Deno.removeSync(LOG_FILE); },});