implement MockLoggerService.ts testing utility

packages/backend/test/misc/MockLoggerService.ts

@@ -0,0 +1,74 @@
+/*
+ * SPDX-FileCopyrightText: hazelnoot and other Sharkey contributors
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+import { jest } from '@jest/globals';
+import { Injectable } from '@nestjs/common';
+import type { KEYWORD } from 'color-convert/conversions.js';
+import type { Config } from '@/config.js';
+import Logger, { type Console } from '@/logger.js';
+import { LoggerService } from '@/core/LoggerService.js';
+import { bindThis } from '@/decorators.js';
+
+/**
+ * Mocked implementation of LoggerService.
+ * Suppresses all log output to prevent console spam, and records calls for assertions.
+ */
+@Injectable()
+export class MockLoggerService extends LoggerService {
+	/**
+	 * Mocked Console implementation.
+	 * All logs from all logger instances will be sent here.
+	 */
+	public readonly console: jest.Mocked<Console> = {
+		error: jest.fn(),
+		warn: jest.fn(),
+		info: jest.fn(),
+		log: jest.fn(),
+		debug: jest.fn(),
+	};
+
+	/**
+	 * Controls the verbose flag for logger instances.
+	 * Defaults to false (not verbose).
+	 */
+	public verbose: boolean;
+
+	constructor(config?: Config) {
+		config ??= { logging: { verbose: false } } as Config;
+		super(config);
+	}
+
+	/**
+	 * Resets the instance to initial state.
+	 * Mocks are reset, and verbose flag is cleared.
+	 */
+	@bindThis
+	public reset() {
+		this.console.error.mockReset();
+		this.console.warn.mockReset();
+		this.console.info.mockReset();
+		this.console.log.mockReset();
+		this.console.debug.mockReset();
+
+		this.verbose = false;
+	}
+
+	/**
+	 * Asserts that no errors and/or warnings have been logged.
+	 */
+	@bindThis
+	public assertNoErrors(opts?: { orWarnings?: boolean }): void {
+		expect(this.console.error).not.toHaveBeenCalled();
+
+		if (opts?.orWarnings) {
+			expect(this.console.warn).not.toHaveBeenCalled();
+		}
+	}
+
+	@bindThis
+	getLogger(domain: string, color?: KEYWORD | undefined): Logger {
+		return new Logger(domain, color, this.verbose, this.console);
+	}
+}