Add comprehensive test suite with Jest covering all library modules

.gitignore

@@ -20,3 +20,5 @@ avatar/.DS_Store
 .env
 
 sipp/csv/servers/
+
+coverage/

jest.config.js

@@ -0,0 +1,10 @@
+module.exports = {
+  testMatch: ['**/test/**/*.test.js'],
+  testEnvironment: 'node',
+  clearMocks: true,
+  collectCoverageFrom: [
+    'lib/**/*.js',
+    'metrics-server.js'
+  ],
+  coverageDirectory: 'coverage'
+};

package.json

@@ -21,6 +21,12 @@
     },
     "scripts": {
         "start": "node server.js",
-        "metrics": "node metrics-server.js"
+        "metrics": "node metrics-server.js",
+        "test": "jest",
+        "test:coverage": "jest --coverage"
+    },
+    "devDependencies": {
+        "jest": "^30.3.0",
+        "supertest": "^7.2.2"
     }
 }

test/lib/config.test.js

@@ -0,0 +1,187 @@
+const fs = require('fs');
+const path = require('path');
+
+describe('ConfigLoader', () => {
+  let ConfigLoader;
+  let originalEnv;
+  let originalArgv;
+
+  beforeEach(() => {
+    originalEnv = { ...process.env };
+    originalArgv = [...process.argv];
+
+    // Clear relevant env vars
+    delete process.env.TARGET_SERVER;
+    delete process.env.APIKEY;
+    delete process.env.MAX_DOMAIN;
+    delete process.env.MAX_RESELLERS;
+    delete process.env.PEAK_CPS;
+    delete process.env.REGISTRATION_PCT;
+    delete process.env.SEED;
+
+    // Fresh import each time to avoid state leakage
+    jest.resetModules();
+    ({ ConfigLoader } = require('../../lib/config'));
+  });
+
+  afterEach(() => {
+    process.env = originalEnv;
+    process.argv = originalArgv;
+    jest.restoreAllMocks();
+  });
+
+  describe('single server mode', () => {
+    beforeEach(() => {
+      jest.spyOn(fs, 'existsSync').mockImplementation((p) => {
+        if (p.endsWith('servers.json')) return false;
+        return false;
+      });
+    });
+
+    test('loads from env when no servers.json', () => {
+      process.env.TARGET_SERVER = 'test.example.com';
+      process.env.APIKEY = 'testkey123';
+
+      const loader = new ConfigLoader();
+      const config = loader.load();
+
+      expect(config.mode).toBe('single');
+      expect(config.servers).toHaveLength(1);
+      expect(config.selectedServer.hostname).toBe('test.example.com');
+      expect(config.selectedServer.apikey).toBe('testkey123');
+      expect(config.selectedServer.id).toBe('default');
+    });
+
+    test('throws when TARGET_SERVER missing', () => {
+      process.env.APIKEY = 'testkey123';
+
+      const loader = new ConfigLoader();
+      expect(() => loader.load()).toThrow('TARGET_SERVER');
+    });
+
+    test('throws when APIKEY missing', () => {
+      process.env.TARGET_SERVER = 'test.example.com';
+
+      const loader = new ConfigLoader();
+      expect(() => loader.load()).toThrow('APIKEY');
+    });
+
+    test('applies defaults for optional fields', () => {
+      process.env.TARGET_SERVER = 'test.example.com';
+      process.env.APIKEY = 'testkey123';
+
+      const loader = new ConfigLoader();
+      const config = loader.load();
+
+      expect(config.selectedServer.maxDomains).toBe(10);
+      expect(config.selectedServer.peakCps).toBe(10);
+      expect(config.selectedServer.registrationPct).toBe(0.8);
+    });
+  });
+
+  describe('multi server mode', () => {
+    const serversJson = {
+      servers: [
+        { id: 'prod1', hostname: 'prod1.example.com', apikey: 'key1', maxDomains: 20 },
+        { id: 'prod2', hostname: 'prod2.example.com', apikey: 'key2', maxDomains: 30 }
+      ]
+    };
+
+    beforeEach(() => {
+      jest.spyOn(fs, 'existsSync').mockImplementation((p) => {
+        if (p.endsWith('servers.json')) return true;
+        return false;
+      });
+      jest.spyOn(fs, 'readFileSync').mockImplementation((p) => {
+        if (p.endsWith('servers.json')) return JSON.stringify(serversJson);
+        return '';
+      });
+    });
+
+    test('reads and parses servers.json correctly', () => {
+      process.argv = ['node', 'server.js', '--server', 'prod1'];
+
+      const loader = new ConfigLoader();
+      const config = loader.load();
+
+      expect(config.mode).toBe('multi');
+      expect(config.servers).toHaveLength(2);
+      expect(config.selectedServer.id).toBe('prod1');
+      expect(config.selectedServer.hostname).toBe('prod1.example.com');
+    });
+
+    test('throws without --server flag', () => {
+      process.argv = ['node', 'server.js'];
+
+      const loader = new ConfigLoader();
+      expect(() => loader.load()).toThrow('--server');
+    });
+
+    test('throws for unknown server ID', () => {
+      process.argv = ['node', 'server.js', '--server', 'unknown'];
+
+      const loader = new ConfigLoader();
+      expect(() => loader.load()).toThrow("Server 'unknown' not found");
+    });
+
+    test('throws on invalid JSON', () => {
+      jest.spyOn(fs, 'readFileSync').mockReturnValue('not json');
+
+      process.argv = ['node', 'server.js', '--server', 'prod1'];
+      const loader = new ConfigLoader();
+      expect(() => loader.load()).toThrow('Failed to load servers.json');
+    });
+
+    test('throws when servers array is missing', () => {
+      jest.spyOn(fs, 'readFileSync').mockReturnValue(JSON.stringify({ notServers: [] }));
+
+      process.argv = ['node', 'server.js', '--server', 'prod1'];
+      const loader = new ConfigLoader();
+      expect(() => loader.load()).toThrow('servers');
+    });
+  });
+
+  describe('validation', () => {
+    beforeEach(() => {
+      jest.spyOn(fs, 'existsSync').mockImplementation((p) => {
+        if (p.endsWith('servers.json')) return false;
+        return false;
+      });
+    });
+
+    test('throws for invalid hostname format', () => {
+      process.env.TARGET_SERVER = 'invalid hostname!';
+      process.env.APIKEY = 'testkey';
+
+      const loader = new ConfigLoader();
+      expect(() => loader.load()).toThrow('Invalid hostname');
+    });
+
+    test('throws for maxDomains < 1', () => {
+      process.env.TARGET_SERVER = 'test.example.com';
+      process.env.APIKEY = 'testkey';
+      process.env.MAX_DOMAIN = '-1';
+
+      const loader = new ConfigLoader();
+      expect(() => loader.load()).toThrow('maxDomains');
+    });
+
+    test('throws for peakCps <= 0', () => {
+      process.env.TARGET_SERVER = 'test.example.com';
+      process.env.APIKEY = 'testkey';
+      process.env.PEAK_CPS = '-1';
+
+      const loader = new ConfigLoader();
+      expect(() => loader.load()).toThrow('peakCps');
+    });
+
+    test('throws for registrationPct out of range', () => {
+      process.env.TARGET_SERVER = 'test.example.com';
+      process.env.APIKEY = 'testkey';
+      process.env.REGISTRATION_PCT = '1.5';
+
+      const loader = new ConfigLoader();
+      expect(() => loader.load()).toThrow('registrationPct');
+    });
+  });
+});