ci(docs-infra): rename 'upload-server' to 'preview-server'

The server no longer has files uploaded to it. Instead it is more
accurate to refer to it as dealing with "previews" of PRs.

aio/aio-builds-setup/dockerbuild/scripts-js/test/preview-server/build-events.spec.ts

@@ -0,0 +1,58 @@
+// Imports
+import {ChangedPrVisibilityEvent, CreatedBuildEvent} from '../../lib/preview-server/build-events';
+
+// Tests
+describe('ChangedPrVisibilityEvent', () => {
+  let evt: ChangedPrVisibilityEvent;
+
+  beforeEach(() => evt = new ChangedPrVisibilityEvent(42, ['foo', 'bar'], true));
+
+
+  it('should have a static \'type\' property', () => {
+    expect(ChangedPrVisibilityEvent.type).toBe('pr.changedVisibility');
+  });
+
+
+  it('should have a \'pr\' property', () => {
+    expect(evt.pr).toBe(42);
+  });
+
+
+  it('should have a \'shas\' property', () => {
+    expect(evt.shas).toEqual(['foo', 'bar']);
+  });
+
+
+  it('should have an \'isPublic\' property', () => {
+    expect(evt.isPublic).toBe(true);
+  });
+
+});
+
+
+describe('CreatedBuildEvent', () => {
+  let evt: CreatedBuildEvent;
+
+  beforeEach(() => evt = new CreatedBuildEvent(42, 'bar', true));
+
+
+  it('should have a static \'type\' property', () => {
+    expect(CreatedBuildEvent.type).toBe('build.created');
+  });
+
+
+  it('should have a \'pr\' property', () => {
+    expect(evt.pr).toBe(42);
+  });
+
+
+  it('should have a \'sha\' property', () => {
+    expect(evt.sha).toBe('bar');
+  });
+
+
+  it('should have an \'isPublic\' property', () => {
+    expect(evt.isPublic).toBe(true);
+  });
+
+});