log4js-node/test/tap/configuration-test.js

const { test } = require("tap");
const sandbox = require("@log4js-node/sandboxed-module");
const realFS = require("fs");

const modulePath = "some/path/to/mylog4js.json";
const pathsChecked = [];

let fakeFS = {};
let dependencies;
let fileRead;

test("log4js configure", batch => {
  batch.beforeEach(done => {
    fileRead = 0;

    fakeFS = {
      realpath: realFS.realpath, // fs-extra looks for this
      ReadStream: realFS.ReadStream, // need to define these, because graceful-fs uses them
      WriteStream: realFS.WriteStream,
      read: realFS.read,
      closeSync: () => {},
      config: {
        appenders: {
          console: {
            type: "console",
            layout: { type: "messagePassThrough" }
          }
        },
        categories: {
          default: {
            appenders: ["console"],
            level: "INFO"
          }
        }
      },
      readdirSync: dir => require("fs").readdirSync(dir),
      readFileSync: (file, encoding) => {
        fileRead += 1;
        batch.type(file, "string");
        batch.equal(file, modulePath);
        batch.equal(encoding, "utf8");
        return JSON.stringify(fakeFS.config);
      },
      statSync: path => {
        pathsChecked.push(path);
        if (path === modulePath) {
          return { mtime: new Date() };
        }
        throw new Error("no such file");
      }
    };

    dependencies = {
      requires: {
        fs: fakeFS
      }
    };

    done();
  });

  batch.test(
    "when configuration file loaded via LOG4JS_CONFIG env variable",
    t => {
      process.env.LOG4JS_CONFIG = "some/path/to/mylog4js.json";

      const log4js = sandbox.require("../../lib/log4js", dependencies);

      log4js.getLogger("test-logger");
      t.equal(fileRead, 1, "should load the specified local config file");

      delete process.env.LOG4JS_CONFIG;

      t.end();
    }
  );

  batch.test(
    "when configuration is set via configure() method call, return the log4js object",
    t => {
      const log4js = sandbox
        .require("../../lib/log4js", dependencies)
        .configure(fakeFS.config);
      t.type(
        log4js,
        "object",
        "Configure method call should return the log4js object!"
      );

      const log = log4js.getLogger("daemon");
      t.type(
        log,
        "object",
        "log4js object, returned by configure(...) method should be able to create log object."
      );
      t.type(log.info, "function");

      t.end();
    }
  );

  batch.end();
});