feat: Add a unit test target (jest) to the UI extension and run it in CI (#1192)

- Introduce test targets.
- Adding additional tests.

Related to: https://github.com/harvester/harvester/issues/11892

Signed-off-by: Volker Theile <vtheile@suse.com>

pkg/harvester/utils/__tests__/feature-flags.test.js

@@ -0,0 +1,37 @@
+import { featureEnabled } from '../feature-flags';
+
+describe('featureEnabled', () => {
+  it('should enable a feature from the version it was released in', () => {
+    expect(featureEnabled('hotplugNic', 'v1.7.0')).toBe(true);
+    expect(featureEnabled('hotplugNic', 'v1.8.2')).toBe(true);
+  });
+
+  it('should not enable a feature before the version it was released in', () => {
+    expect(featureEnabled('hotplugNic', 'v1.6.1')).toBe(false);
+    expect(featureEnabled('hotplugCdRom', 'v1.7.1')).toBe(false);
+  });
+
+  it('should ignore pre-release suffixes of the server version', () => {
+    expect(featureEnabled('hotplugCdRom', 'v1.8.0-rc1')).toBe(true);
+    expect(featureEnabled('hotplugCdRom', 'v1.8.0-dev-20260101')).toBe(true);
+  });
+
+  it('should return false for unknown features', () => {
+    expect(featureEnabled('doesNotExist', 'v1.8.0')).toBe(false);
+  });
+
+  it('should not enable anything for versions that are no longer supported', () => {
+    const spy = jest.spyOn(console, 'error').mockImplementation(() => {});
+
+    expect(featureEnabled('cpuPinning', 'v1.2.0')).toBe(false);
+
+    spy.mockRestore();
+  });
+
+  it('should return the same result for repeated calls with different arguments', () => {
+    expect(featureEnabled('hotplugNic', 'v1.6.0')).toBe(false);
+    expect(featureEnabled('hotplugNic', 'v1.7.0')).toBe(true);
+    expect(featureEnabled('hotplugNic', 'v1.6.0')).toBe(false);
+    expect(featureEnabled('hotplugNic', 'v1.7.0')).toBe(true);
+  });
+});