message: MINOR: Fix LoggerManagerTest.
  The test was enabling all logging channels in the real LoggerManager instance,
  leaving them enabled for any other tests.
diff: @@ -11,6 +11,7 @@ import * as sinon from "sinon";
  import { ConsoleChannel } from "../lib/Logger/ConsoleChannel";
  import { ILogger, LogLevel } from "../lib/Logger/ILogger";
  +import { ILoggerManager } from "../lib/Logger/ILoggerManager";
  import { LoggerManager } from "../lib/Logger/LoggerManager";
  import { LoggerManagerImpl } from "../lib/Logger/LoggerManagerImpl";
  import { MultiChannel } from "../lib/Logger/MultiChannel";
  @@ -112,13 +113,21 @@ describe("LoggerManager", function() {
  describe("Check channel compliancy", function() {
  const sandbox = sinon.createSandbox();
  - LoggerManager.instance.setLogLevelForAll(LogLevel.Trace);
  + let loggerManager: ILoggerManager;
  +
  + beforeEach(() => {
  + loggerManager = new LoggerManagerImpl();
  + });
  +
  + afterEach(() => {
  + sandbox.restore();
  + });
  it("Check channels logging abilities", function() {
  // Arrange
  - const consoleChannel = LoggerManager.instance.channel;
  + const consoleChannel = loggerManager.channel;
  const stubs = sandbox.stub(consoleChannel);
  - const logger = LoggerManager.instance.create("foo");
  + const logger = loggerManager.create("foo", { level: LogLevel.Trace });
  // Act
  printAll(logger, "some message");
  @@ -134,16 +143,15 @@ describe("LoggerManager", function() {
  it("Check channels logging abilities after switching channels", function() {
  // Arrange
  - sandbox.restore();
  - const oldChannel = LoggerManager.instance.channel;
  + const oldChannel = loggerManager.channel;
  const oldChannelStub = sandbox.stub(oldChannel);
  const newChannel = new ConsoleChannel();
  const newChannelStub = sandbox.stub(newChannel);
  - LoggerManager.instance.setChannel(newChannel);
  + loggerManager.setChannel(newChannel);
  - const logger = LoggerManager.instance.create("foo");
  + const logger = loggerManager.create("foo", { level: LogLevel.Trace });
  // Act
  printAll(logger, "some message");
  @@ -172,9 +180,9 @@ describe("LoggerManager", function() {
  const channel1Stub = sandbox.stub(channel1);
  const channel2Stub = sandbox.stub(channel2);
  - LoggerManager.instance.setChannel(multiChannel);
  + loggerManager.setChannel(multiChannel);
  - const logger = LoggerManager.instance.create("foo");
  + const logger = loggerManager.create("foo", { level: LogLevel.Trace });
  // Act
  printAll(logger, "some message");
  