refactor: Make Logger an interface.

src/logging/LazyLoggerFactory.ts

@@ -4,7 +4,7 @@ import type { LoggerFactory } from './LoggerFactory';
 import type { LogLevel } from './LogLevel';
 
 /**
- * Temporary {@link LoggerFactory} that creates buffered {@link WrappingLogger}s
+ * Temporary {@link LoggerFactory} that buffers log messages in memory
  * until the {@link TemporaryLoggerFactory#switch} method is called.
  */
 class TemporaryLoggerFactory implements LoggerFactory {

test/unit/logging/Logger.test.ts

@@ -1,44 +1,95 @@
-import { BaseLogger } from '../../../src/logging/Logger';
+import { BaseLogger, WrappingLogger } from '../../../src/logging/Logger';
+import type { SimpleLogger } from '../../../src/logging/Logger';
 
-describe('BaseLogger', (): void => {
-  let logger: BaseLogger;
-  beforeEach(async(): Promise<void> => {
-    logger = new (BaseLogger as any)();
-    logger.log = jest.fn();
-  });
+describe('Logger', (): void => {
+  describe('a BaseLogger', (): void => {
+    let logger: BaseLogger;
 
-  it('Error delegates to log.', async(): Promise<void> => {
-    logger.error('my message');
-    expect(logger.log).toHaveBeenCalledTimes(1);
-    expect(logger.log).toHaveBeenCalledWith('error', 'my message');
-  });
+    beforeEach(async(): Promise<void> => {
+      logger = new (BaseLogger as any)();
+      logger.log = jest.fn();
+    });
 
-  it('Warn delegates to log.', async(): Promise<void> => {
-    logger.warn('my message');
-    expect(logger.log).toHaveBeenCalledTimes(1);
-    expect(logger.log).toHaveBeenCalledWith('warn', 'my message');
-  });
+    it('delegates error to log.', async(): Promise<void> => {
+      logger.error('my message');
+      expect(logger.log).toHaveBeenCalledTimes(1);
+      expect(logger.log).toHaveBeenCalledWith('error', 'my message');
+    });
 
-  it('Info delegates to log.', async(): Promise<void> => {
-    logger.info('my message');
-    expect(logger.log).toHaveBeenCalledTimes(1);
-    expect(logger.log).toHaveBeenCalledWith('info', 'my message');
-  });
-  it('Verbose delegates to log.', async(): Promise<void> => {
-    logger.verbose('my message');
-    expect(logger.log).toHaveBeenCalledTimes(1);
-    expect(logger.log).toHaveBeenCalledWith('verbose', 'my message');
-  });
+    it('warn delegates to log.', async(): Promise<void> => {
+      logger.warn('my message');
+      expect(logger.log).toHaveBeenCalledTimes(1);
+      expect(logger.log).toHaveBeenCalledWith('warn', 'my message');
+    });
+
+    it('info delegates to log.', async(): Promise<void> => {
+      logger.info('my message');
+      expect(logger.log).toHaveBeenCalledTimes(1);
+      expect(logger.log).toHaveBeenCalledWith('info', 'my message');
+    });
+
+    it('verbose delegates to log.', async(): Promise<void> => {
+      logger.verbose('my message');
+      expect(logger.log).toHaveBeenCalledTimes(1);
+      expect(logger.log).toHaveBeenCalledWith('verbose', 'my message');
+    });
+
+    it('debug delegates to log.', async(): Promise<void> => {
+      logger.debug('my message');
+      expect(logger.log).toHaveBeenCalledTimes(1);
+      expect(logger.log).toHaveBeenCalledWith('debug', 'my message');
+    });
 
-  it('Debug delegates to log.', async(): Promise<void> => {
-    logger.debug('my message');
-    expect(logger.log).toHaveBeenCalledTimes(1);
-    expect(logger.log).toHaveBeenCalledWith('debug', 'my message');
+    it('silly delegates to log.', async(): Promise<void> => {
+      logger.silly('my message');
+      expect(logger.log).toHaveBeenCalledTimes(1);
+      expect(logger.log).toHaveBeenCalledWith('silly', 'my message');
+    });
   });
 
-  it('Silly delegates to log.', async(): Promise<void> => {
-    logger.silly('my message');
-    expect(logger.log).toHaveBeenCalledTimes(1);
-    expect(logger.log).toHaveBeenCalledWith('silly', 'my message');
+  describe('a WrappingLogger', (): void => {
+    let logger: SimpleLogger;
+    let wrapper: WrappingLogger;
+
+    beforeEach(async(): Promise<void> => {
+      logger = { log: jest.fn() };
+      wrapper = new WrappingLogger(logger);
+    });
+
+    it('error delegates to the internal logger.', async(): Promise<void> => {
+      wrapper.error('my message');
+      expect(logger.log).toHaveBeenCalledTimes(1);
+      expect(logger.log).toHaveBeenCalledWith('error', 'my message');
+    });
+
+    it('warn delegates to the internal logger.', async(): Promise<void> => {
+      wrapper.warn('my message');
+      expect(logger.log).toHaveBeenCalledTimes(1);
+      expect(logger.log).toHaveBeenCalledWith('warn', 'my message');
+    });
+
+    it('info delegates to the internal logger.', async(): Promise<void> => {
+      wrapper.info('my message');
+      expect(logger.log).toHaveBeenCalledTimes(1);
+      expect(logger.log).toHaveBeenCalledWith('info', 'my message');
+    });
+
+    it('verbose delegates to the internal logger.', async(): Promise<void> => {
+      wrapper.verbose('my message');
+      expect(logger.log).toHaveBeenCalledTimes(1);
+      expect(logger.log).toHaveBeenCalledWith('verbose', 'my message');
+    });
+
+    it('debug delegates to the internal logger.', async(): Promise<void> => {
+      wrapper.debug('my message');
+      expect(logger.log).toHaveBeenCalledTimes(1);
+      expect(logger.log).toHaveBeenCalledWith('debug', 'my message');
+    });
+
+    it('silly delegates to the internal logger.', async(): Promise<void> => {
+      wrapper.silly('my message');
+      expect(logger.log).toHaveBeenCalledTimes(1);
+      expect(logger.log).toHaveBeenCalledWith('silly', 'my message');
+    });
   });
 });