1 files changed, 118 insertions, 0 deletions
diff --git a/ui/src/common/feature_flags_unittest.ts b/ui/src/common/feature_flags_unittest.ts
new file mode 100644
index 000000000..d2cb97beb
--- /dev/null
+++ b/ui/src/common/feature_flags_unittest.ts
@@ -0,0 +1,118 @@
+// Copyright (C) 2021 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+import {FlagsForTesting as Flags, FlagStore} from './feature_flags';
+
+class TestFlagStore implements FlagStore {
+  o: object = {};
+
+  load(): object {
+    return this.o;
+  }
+
+  save(o: object): void {
+    this.o = o;
+  }
+}
+
+test('create flag', () => {
+  const flags = new Flags(new TestFlagStore());
+  const myFlag = flags.register({
+    id: 'myFlag',
+    defaultValue: false,
+    description: '',
+  });
+  expect(myFlag.get()).toEqual(false);
+  expect(myFlag.isOverridden()).toEqual(false);
+});
+
+test('registering the same flag twice is an error', () => {
+  const flags = new Flags(new TestFlagStore());
+  flags.register({
+    id: 'foo',
+    defaultValue: false,
+    description: '',
+  });
+  expect(() => flags.register({
+    id: 'foo',
+    defaultValue: false,
+    description: '',
+  })).toThrow('Flag with id "foo" is already registered.');
+});
+
+test('can override', () => {
+  const flags = new Flags(new TestFlagStore());
+  const foo = flags.register({
+    id: 'foo',
+    defaultValue: false,
+    description: '',
+  });
+  foo.set(true);
+  expect(foo.isOverridden()).toEqual(true);
+  expect(foo.get()).toEqual(true);
+});
+
+test('overrides are persisted', () => {
+  const store = new TestFlagStore();
+  const flagsA = new Flags(store);
+  const fooA = flagsA.register({
+    id: 'foo',
+    defaultValue: true,
+    description: 'some description',
+  });
+
+  fooA.set(true);
+
+  const flagsB = new Flags(store);
+  const fooB = flagsB.register({
+    id: 'foo',
+    defaultValue: false,
+    description: 'a new description',
+  });
+
+  expect(fooB.get()).toEqual(true);
+  expect(fooB.isOverridden()).toEqual(true);
+});
+
+test('flags can be reset', () => {
+  const flags = new Flags(new TestFlagStore());
+  const foo = flags.register({
+    id: 'foo',
+    defaultValue: false,
+    description: 'some description',
+  });
+
+  foo.set(false);
+  foo.reset();
+  expect(foo.get()).toEqual(false);
+  expect(foo.isOverridden()).toEqual(false);
+});
+
+test('corrupt store is ignored', () => {
+  class Store {
+    load(): object {
+      return {'foo': 'bad state'};
+    }
+
+    save(_: object): void {}
+  }
+  const flags = new Flags(new Store());
+  const foo = flags.register({
+    id: 'foo',
+    defaultValue: false,
+    description: 'some description',
+  });
+
+  expect(foo.isOverridden()).toEqual(false);
+});