fix(aio): ignore private exports

Closes #14992

aio/transforms/angular.io-package/processors/markBarredODocsAsPrivate.spec.js

@@ -0,0 +1,28 @@
+const testPackage = require('../../helpers/test-package');
+const processorFactory = require('./markBarredODocsAsPrivate');
+const Dgeni = require('dgeni');
+
+describe('generateApiListDoc processor', () => {
+
+  it('should be available on the injector', () => {
+    const dgeni = new Dgeni([testPackage('angular.io-package')]);
+    const injector = dgeni.configureInjector();
+    const processor = injector.get('markBarredODocsAsPrivate');
+    expect(processor.$process).toBeDefined();
+    expect(processor.$runAfter).toContain('readTypeScriptModules');
+    expect(processor.$runBefore).toContain('adding-extra-docs');
+  });
+
+  it('should mark docs starting with barred-o ɵ as private', () => {
+    const processor = processorFactory();
+    const docs = [
+      { name: 'ɵPrivate' },
+      { name: 'public' }
+    ]
+    processor.$process(docs);
+
+    expect(docs[0].privateExport).toBeTruthy();
+    expect(docs[1].privateExport).toBeFalsy();
+  });
+});
+