diff --git a/tests/api.test.js b/tests/api.test.js
new file mode 100644
index 0000000..46398cb
--- /dev/null
+++ b/tests/api.test.js
@@ -0,0 +1,87 @@
+const request = require('supertest');
+const app = require('../src/app');
+
+describe('API Endpoints', () => {
+  describe('GET /api/system', () => {
+    it('should return system information', async() => {
+      const response = await request(app)
+        .get('/api/system')
+        .expect(200);
+
+      expect(response.body.success).toBe(true);
+      expect(response.body.data).toHaveProperty('hostname');
+      expect(response.body.data).toHaveProperty('platform');
+      expect(response.body.data).toHaveProperty('cpus');
+      expect(response.body.data).toHaveProperty('totalMemory');
+      expect(typeof response.body.data.cpus).toBe('number');
+    });
+  });
+
+  describe('GET /api/memory', () => {
+    it('should return memory information', async() => {
+      const response = await request(app)
+        .get('/api/memory')
+        .expect(200);
+
+      expect(response.body.success).toBe(true);
+      expect(response.body.data).toHaveProperty('system');
+      expect(response.body.data).toHaveProperty('process');
+      expect(response.body.data.system).toHaveProperty('total');
+      expect(response.body.data.system).toHaveProperty('used');
+      expect(response.body.data.process).toHaveProperty('rss');
+    });
+  });
+
+  describe('GET /api/process', () => {
+    it('should return process information', async() => {
+      const response = await request(app)
+        .get('/api/process')
+        .expect(200);
+
+      expect(response.body.success).toBe(true);
+      expect(response.body.data).toHaveProperty('pid');
+      expect(response.body.data).toHaveProperty('uptime');
+      expect(response.body.data).toHaveProperty('version');
+      expect(typeof response.body.data.pid).toBe('number');
+    });
+  });
+
+  describe('GET /api/metrics', () => {
+    it('should return application metrics', async() => {
+      const response = await request(app)
+        .get('/api/metrics')
+        .expect(200);
+
+      expect(response.body.success).toBe(true);
+      expect(response.body.data).toHaveProperty('counters');
+      expect(response.body.data).toHaveProperty('gauges');
+      expect(response.body.data).toHaveProperty('histograms');
+      expect(response.body.data).toHaveProperty('runtime');
+      expect(Array.isArray(response.body.data.counters)).toBe(true);
+    });
+  });
+
+  describe('GET /api/test', () => {
+    it('should return test response', async() => {
+      const response = await request(app)
+        .get('/api/test')
+        .expect(200);
+
+      expect(response.body.success).toBe(true);
+      expect(response.body.message).toBe('API is working correctly');
+      expect(response.body).toHaveProperty('version');
+      expect(response.body).toHaveProperty('timestamp');
+    });
+  });
+
+  describe('Error handling', () => {
+    it('should return 404 for unknown API endpoints', async() => {
+      const response = await request(app)
+        .get('/api/nonexistent')
+        .expect(404);
+
+      expect(response.body).toHaveProperty('error');
+      expect(response.body.error).toBe('Not Found');
+    });
+  });
+});
diff --git a/tests/app.test.js b/tests/app.test.js
new file mode 100644
index 0000000..e3d059f
--- /dev/null
+++ b/tests/app.test.js
@@ -0,0 +1,93 @@
+const request = require('supertest');
+const app = require('../src/app');
+
+describe('Main Application', () => {
+  describe('Static file serving', () => {
+    it('should serve the main dashboard page', async() => {
+      const response = await request(app)
+        .get('/')
+        .expect(200);
+
+      expect(response.headers['content-type']).toMatch(/html/);
+    });
+
+    it('should serve static CSS files', async() => {
+      const response = await request(app)
+        .get('/style.css')
+        .expect(200);
+
+      expect(response.headers['content-type']).toMatch(/css/);
+    });
+
+    it('should serve static JavaScript files', async() => {
+      const response = await request(app)
+        .get('/app.js')
+        .expect(200);
+
+      expect(response.headers['content-type']).toMatch(/javascript/);
+    });
+  });
+
+  describe('Debug endpoints', () => {
+    it('should return debug file information', async() => {
+      const response = await request(app)
+        .get('/debug/files')
+        .expect(200);
+
+      expect(response.body).toHaveProperty('publicPath');
+      expect(response.body).toHaveProperty('files');
+      expect(Array.isArray(response.body.files)).toBe(true);
+    });
+
+    it('should serve test static page', async() => {
+      const response = await request(app)
+        .get('/test-static')
+        .expect(200);
+
+      expect(response.text).toContain('Static File Test');
+      expect(response.headers['content-type']).toMatch(/html/);
+    });
+  });
+
+  describe('Error handling', () => {
+    it('should return 404 for unknown routes', async() => {
+      const response = await request(app)
+        .get('/nonexistent-route')
+        .expect(404);
+
+      expect(response.body).toHaveProperty('error', 'Not Found');
+      expect(response.body).toHaveProperty('url', '/nonexistent-route');
+    });
+  });
+
+  describe('CORS and Security', () => {
+    it('should include CORS headers', async() => {
+      const response = await request(app)
+        .get('/api/system')
+        .expect(200);
+
+      expect(response.headers).toHaveProperty('access-control-allow-origin');
+    });
+
+    it('should include basic Express headers', async() => {
+      const response = await request(app)
+        .get('/')
+        .expect(200);
+
+      // Check for basic Express headers that should be present
+      expect(response.headers).toHaveProperty('x-powered-by', 'Express');
+      expect(response.headers).toHaveProperty('content-type');
+    });
+  });
+
+  describe('Request logging', () => {
+    it('should log requests without errors', async() => {
+      // This test ensures the logging middleware doesn't crash
+      const response = await request(app)
+        .get('/health')
+        .expect(200);
+
+      expect(response.body).toHaveProperty('status', 'healthy');
+    });
+  });
+});
diff --git a/tests/health.test.js b/tests/health.test.js
new file mode 100644
index 0000000..c597d80
--- /dev/null
+++ b/tests/health.test.js
@@ -0,0 +1,103 @@
+const request = require('supertest');
+const app = require('../src/app');
+
+describe('Health Check Endpoints', () => {
+  describe('GET /health', () => {
+    it('should return basic health status', async() => {
+      const response = await request(app)
+        .get('/health')
+        .expect(200);
+
+      expect(response.body).toHaveProperty('status', 'healthy');
+      expect(response.body).toHaveProperty('timestamp');
+      expect(response.body).toHaveProperty('uptime');
+      expect(response.body).toHaveProperty('service', 'harbor-ci-cd-demo');
+      expect(typeof response.body.uptime).toBe('number');
+    });
+  });
+
+  describe('GET /health/detailed', () => {
+    it('should return detailed health information', async() => {
+      const response = await request(app)
+        .get('/health/detailed')
+        .expect(200);
+
+      expect(response.body).toHaveProperty('status');
+      expect(response.body).toHaveProperty('timestamp');
+      expect(response.body).toHaveProperty('service', 'harbor-ci-cd-demo');
+      expect(response.body).toHaveProperty('uptime');
+      expect(response.body).toHaveProperty('memory');
+      expect(response.body).toHaveProperty('loadAverage');
+      expect(response.body).toHaveProperty('environment');
+
+      // Check memory structure
+      expect(response.body.memory).toHaveProperty('status');
+      expect(response.body.memory).toHaveProperty('system');
+      expect(response.body.memory).toHaveProperty('process');
+      expect(response.body.memory.system).toHaveProperty('total');
+      expect(response.body.memory.system).toHaveProperty('used');
+      expect(response.body.memory.system).toHaveProperty('percentage');
+
+      // Check uptime structure
+      expect(response.body.uptime).toHaveProperty('process');
+      expect(response.body.uptime).toHaveProperty('system');
+      expect(typeof response.body.uptime.process).toBe('number');
+      expect(typeof response.body.uptime.system).toBe('number');
+
+      // Check load average
+      expect(Array.isArray(response.body.loadAverage)).toBe(true);
+      expect(response.body.loadAverage).toHaveLength(3);
+    });
+
+    it('should include version information', async() => {
+      const response = await request(app)
+        .get('/health/detailed')
+        .expect(200);
+
+      expect(response.body).toHaveProperty('version');
+    });
+  });
+
+  describe('GET /health/ready', () => {
+    it('should return readiness status', async() => {
+      const response = await request(app)
+        .get('/health/ready')
+        .expect(200);
+
+      expect(response.body).toHaveProperty('status', 'ready');
+      expect(response.body).toHaveProperty('timestamp');
+    });
+  });
+
+  describe('GET /health/live', () => {
+    it('should return liveness status', async() => {
+      const response = await request(app)
+        .get('/health/live')
+        .expect(200);
+
+      expect(response.body).toHaveProperty('status', 'alive');
+      expect(response.body).toHaveProperty('timestamp');
+      expect(response.body).toHaveProperty('uptime');
+      expect(typeof response.body.uptime).toBe('number');
+    });
+  });
+
+  describe('Health status validation', () => {
+    it('should return valid timestamp format', async() => {
+      const response = await request(app)
+        .get('/health')
+        .expect(200);
+
+      const timestamp = new Date(response.body.timestamp);
+      expect(timestamp).toBeInstanceOf(Date);
+      expect(timestamp.getTime()).not.toBeNaN();
+    });
+
+    it('should return consistent service name across endpoints', async() => {
+      const basicHealth = await request(app).get('/health');
+      const detailedHealth = await request(app).get('/health/detailed');
+
+      expect(basicHealth.body.service).toBe(detailedHealth.body.service);
+    });
+  });
+});
diff --git a/tests/metrics.test.js b/tests/metrics.test.js
new file mode 100644
index 0000000..522ab62
--- /dev/null
+++ b/tests/metrics.test.js
@@ -0,0 +1,121 @@
+const {
+  incrementCounter,
+  setGauge,
+  recordHistogram,
+  getMetrics,
+  resetMetrics
+} = require('../src/utils/metrics');
+
+describe('Metrics Utility', () => {
+  beforeEach(() => {
+    resetMetrics();
+  });
+
+  describe('incrementCounter', () => {
+    it('should increment a counter', () => {
+      incrementCounter('test_counter');
+      incrementCounter('test_counter');
+
+      const metrics = getMetrics();
+      const counter = metrics.counters.find(c => c.name === 'test_counter');
+
+      expect(counter).toBeDefined();
+      expect(counter.value).toBe(2);
+    });
+
+    it('should handle counters with labels', () => {
+      incrementCounter('http_requests', { method: 'GET' });
+      incrementCounter('http_requests', { method: 'POST' });
+      incrementCounter('http_requests', { method: 'GET' });
+
+      const metrics = getMetrics();
+      const getCounter = metrics.counters.find(c =>
+        c.name === 'http_requests' && c.labels.method === 'GET'
+      );
+      const postCounter = metrics.counters.find(c =>
+        c.name === 'http_requests' && c.labels.method === 'POST'
+      );
+
+      expect(getCounter.value).toBe(2);
+      expect(postCounter.value).toBe(1);
+    });
+  });
+
+  describe('setGauge', () => {
+    it('should set a gauge value', () => {
+      setGauge('memory_usage', 85.5);
+
+      const metrics = getMetrics();
+      const gauge = metrics.gauges.find(g => g.name === 'memory_usage');
+
+      expect(gauge).toBeDefined();
+      expect(gauge.value).toBe(85.5);
+    });
+
+    it('should update existing gauge values', () => {
+      setGauge('cpu_usage', 50);
+      setGauge('cpu_usage', 75);
+
+      const metrics = getMetrics();
+      const gauge = metrics.gauges.find(g => g.name === 'cpu_usage');
+
+      expect(gauge.value).toBe(75);
+    });
+  });
+
+  describe('recordHistogram', () => {
+    it('should record histogram values', () => {
+      recordHistogram('response_time', 100);
+      recordHistogram('response_time', 150);
+      recordHistogram('response_time', 200);
+
+      const metrics = getMetrics();
+      const histogram = metrics.histograms.find(h => h.name === 'response_time');
+
+      expect(histogram).toBeDefined();
+      expect(histogram.count).toBe(3);
+      expect(histogram.sum).toBe(450);
+      expect(histogram.average).toBe(150);
+      expect(histogram.min).toBe(100);
+      expect(histogram.max).toBe(200);
+    });
+  });
+
+  describe('getMetrics', () => {
+    it('should return all metrics with runtime info', () => {
+      incrementCounter('test_counter');
+      setGauge('test_gauge', 42);
+      recordHistogram('test_histogram', 100);
+
+      const metrics = getMetrics();
+
+      expect(metrics).toHaveProperty('counters');
+      expect(metrics).toHaveProperty('gauges');
+      expect(metrics).toHaveProperty('histograms');
+      expect(metrics).toHaveProperty('runtime');
+      expect(metrics).toHaveProperty('timestamp');
+
+      expect(metrics.counters).toHaveLength(1);
+      expect(metrics.gauges).toHaveLength(1);
+      expect(metrics.histograms).toHaveLength(1);
+
+      expect(metrics.runtime).toHaveProperty('uptime_seconds');
+      expect(metrics.runtime).toHaveProperty('memory_usage_bytes');
+    });
+  });
+
+  describe('resetMetrics', () => {
+    it('should clear all metrics', () => {
+      incrementCounter('test_counter');
+      setGauge('test_gauge', 42);
+      recordHistogram('test_histogram', 100);
+
+      resetMetrics();
+
+      const metrics = getMetrics();
+      expect(metrics.counters).toHaveLength(0);
+      expect(metrics.gauges).toHaveLength(0);
+      expect(metrics.histograms).toHaveLength(0);
+    });
+  });
+});