d-logger/test/logger.json-formatter.test.js

import { assert, assertEquals } from "@std/assert";
import Logger from "../lib/logger.ts";
import {
  clearCapturedLogs,
  getCapturedLogs,
  getFirstLogAsJSON,
  setupMocks,
} from "./helpers/logger-test-helpers.js";

// Setup and teardown for all tests
setupMocks();

Deno.test("Logger JSON Formatter - Basic JSON Output - should produce valid JSON output", () => {
  clearCapturedLogs();
  const logger = new Logger({ format: "json" });
  logger.info("test message");

  assertEquals(getCapturedLogs().length, 1);
  const logOutput = getCapturedLogs()[0];

  // Should be valid JSON
  JSON.parse(logOutput);
});

Deno.test("Logger JSON Formatter - Basic JSON Output - should include all required fields in JSON output", () => {
  clearCapturedLogs();
  const logger = new Logger({ format: "json", callerLevel: "info" });
  logger.info("test message");

  const parsed = getFirstLogAsJSON();

  assertEquals(parsed.level, "info");
  assertEquals(parsed.levelNumber, 2);
  assertEquals(parsed.msg, "test message");
  assertEquals(typeof parsed.time, "string");
  assertEquals(typeof parsed.pid, "number");
  assertEquals(typeof parsed.hostname, "string");
  assert(parsed.callerFile);
  assertEquals(typeof parsed.callerLine, "number");
});

Deno.test("Logger JSON Formatter - Basic JSON Output - should format timestamp correctly based on time option", () => {
  clearCapturedLogs();
  const logger = new Logger({ format: "json", time: "short" });
  logger.info("test message");

  const parsed = getFirstLogAsJSON();
  // Should be short format, not ISO
  assert(parsed.time.match(/^\d{4}-\d{2}-\d{2} \d{2}:\d{2}$/));
  assert(!parsed.time.includes("T"));
  assert(!parsed.time.includes("Z"));
});

Deno.test("Logger JSON Formatter - JSON Error Handling - should handle circular references in log entry", () => {
  clearCapturedLogs();
  const logger = new Logger({ format: "json" });

  // Create a circular reference by modifying the logger's formatters
  const originalJsonFormatter = logger.formatters.json;
  logger.formatters.json = function (logEntry) {
    // Add a circular reference to the logEntry
    const circular = { self: null };
    circular.self = circular;
    logEntry.circular = circular;

    // Call the original formatter which should handle the error
    return originalJsonFormatter.call(this, logEntry);
  };

  logger.info("test with circular reference");

  const logOutput = getCapturedLogs()[0];
  // Should be valid JSON despite circular reference
  const parsed = JSON.parse(logOutput);
  // Should contain error information
  assert(parsed.jsonError.includes("JSON stringify failed"));
  assertEquals(parsed.msg, "test with circular reference");
});

Deno.test("Logger JSON Formatter - JSON Error Handling - should handle JSON stringify errors with fallback", () => {
  clearCapturedLogs();
  const logger = new Logger({ format: "json" });

  // Create a problematic object that will cause JSON.stringify to fail
  const problematic = {};
  Object.defineProperty(problematic, "badProp", {
    get() {
      throw new Error("Property access error");
    },
    enumerable: true,
  });

  // Test the formatter directly with a problematic object
  const problematicLogEntry = {
    level: "info",
    msg: "test message",
    problematic: problematic,
  };

  const result = logger.formatters.json(problematicLogEntry);

  // Should produce valid JSON with error info
  const parsed = JSON.parse(result);
  assert(parsed.jsonError.includes("JSON stringify failed"));
});

Deno.test("Logger JSON Formatter - JSON Error Handling - should handle extreme JSON stringify failures", () => {
  clearCapturedLogs();
  const logger = new Logger({ format: "json" });

  // Create an object that will fail even the safe fallback
  // by mocking JSON.stringify to always throw
  const originalStringify = JSON.stringify;
  let callCount = 0;

  JSON.stringify = function (...args) {
    callCount++;
    if (callCount <= 2) {
      throw new Error("Mock JSON error");
    }
    return originalStringify.apply(this, args);
  };

  try {
    const result = logger.formatters.json({
      level: "error",
      msg: "test message",
    });

    // Should still produce valid JSON string even after multiple failures
    const parsed = JSON.parse(result);
    assertEquals(parsed.level, "error");
    assertEquals(parsed.msg, "test message");
    assert(parsed.jsonError.includes("Multiple JSON errors occurred"));
  } finally {
    JSON.stringify = originalStringify;
  }
});

Deno.test("Logger JSON Formatter - Special Characters and Edge Cases - should handle special characters", () => {
  clearCapturedLogs();
  const logger = new Logger({ format: "json" });
  logger.info('Special chars: "quotes", \\backslash, \nnewline');

  // Should produce valid JSON despite special characters
  JSON.parse(getCapturedLogs()[0]);
});

Deno.test("Logger JSON Formatter - Special Characters and Edge Cases - should handle empty messages", () => {
  clearCapturedLogs();
  const logger = new Logger({ format: "json" });
  logger.info("");

  const parsed = getFirstLogAsJSON();
  assertEquals(parsed.msg, "");
});

Deno.test("Logger JSON Formatter - Special Characters and Edge Cases - should handle null and undefined arguments", () => {
  clearCapturedLogs();
  const logger = new Logger({ format: "json" });
  logger.info("Value: %s", null);

  const parsed = getFirstLogAsJSON();
  assertEquals(parsed.msg, "Value: null");
});

Deno.test("Logger JSON Formatter - Special Characters and Edge Cases - should handle very long messages", () => {
  clearCapturedLogs();
  const longMessage = "x".repeat(10000);
  const logger = new Logger({ format: "json" });
  logger.info(longMessage);

  const parsed = getFirstLogAsJSON();
  assertEquals(parsed.msg, longMessage);
});

Deno.test("Logger JSON Formatter - Special Characters and Edge Cases - should handle objects in messages", () => {
  clearCapturedLogs();
  const logger = new Logger({ format: "json" });
  const obj = { key: "value", nested: { prop: 123 } };
  logger.info("Object: %j", obj);

  const parsed = getFirstLogAsJSON();
  assert(parsed.msg.includes('{"key":"value","nested":{"prop":123}}'));
});

Deno.test("Logger JSON Formatter - All Log Levels in JSON - should log error messages with correct level", () => {
  clearCapturedLogs();
  const logger = new Logger({ format: "json" });
  logger.error("error message");

  const parsed = getFirstLogAsJSON();
  assertEquals(parsed.level, "error");
  assertEquals(parsed.levelNumber, 0);
});

Deno.test("Logger JSON Formatter - All Log Levels in JSON - should log warn messages with correct level", () => {
  clearCapturedLogs();
  const logger = new Logger({ format: "json" });
  logger.warn("warn message");

  const parsed = getFirstLogAsJSON();
  assertEquals(parsed.level, "warn");
  assertEquals(parsed.levelNumber, 1);
});

Deno.test("Logger JSON Formatter - All Log Levels in JSON - should log info messages with correct level", () => {
  clearCapturedLogs();
  const logger = new Logger({ format: "json" });
  logger.info("info message");

  const parsed = getFirstLogAsJSON();
  assertEquals(parsed.level, "info");
  assertEquals(parsed.levelNumber, 2);
});

Deno.test("Logger JSON Formatter - All Log Levels in JSON - should log debug messages with correct level", () => {
  clearCapturedLogs();
  const logger = new Logger({ level: "debug", format: "json" });
  logger.debug("debug message");

  const parsed = getFirstLogAsJSON();
  assertEquals(parsed.level, "debug");
  assertEquals(parsed.levelNumber, 3);
});