implement MockEnvService and fix tests

packages/backend/test/misc/MockEnvService.ts

@@ -0,0 +1,66 @@
+/*
+ * SPDX-FileCopyrightText: hazelnoot and other Sharkey contributors
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+import process from 'node:process';
+import { Injectable } from '@nestjs/common';
+import { EnvService } from '@/core/EnvService.js';
+import { CacheManagementService } from '@/core/CacheManagementService.js';
+import { bindThis } from '@/decorators.js';
+
+/**
+ * Implementation of EnvService with support for mocking values.
+ * Environment and package versions are loaded from their original sources, but can be overridden as-needed.
+ */
+@Injectable()
+export class MockEnvService extends EnvService {
+	private _env: Partial<Record<string, string>>;
+
+	constructor(cacheManagementService: CacheManagementService) {
+		super(cacheManagementService);
+		this._env = process.env;
+	}
+
+	/**
+	 * Gets the mocked environment.
+	 * The returned object is "live" and can be modified without polluting the actual application environment.
+	 */
+	get env(): Partial<Record<string, string>> {
+		return this._env;
+	}
+
+	/**
+	 * Replaces the entire mocked environment.
+	 * Pass undefined to restore the original un-mocked values.
+	 */
+	set env(value: Partial<Record<string, string>> | undefined) {
+		if (value !== undefined) {
+			this._env = value;
+		} else {
+			this._env = process.env;
+		}
+	}
+
+	/**
+	 * Overrides the version for a dependency.
+	 * Pass a string or null to override the version, or pass undefined to clear the override and restore the original value.
+	 */
+	@bindThis
+	public setDependencyVersion(dependency: string, version: string | null | undefined) {
+		if (version !== undefined) {
+			this.dependencyVersionCache.set(dependency, version);
+		} else {
+			this.dependencyVersionCache.delete(dependency);
+		}
+	}
+
+	/**
+	 * Resets the mock to initial values.
+	 */
+	@bindThis
+	public mockReset(): void {
+		this._env = process.env;
+		this.dependencyVersionCache.clear();
+	}
+}