Move scene reducer test over

src/views/__tests__/NavigationScenesReducer-test.js

@@ -0,0 +1,330 @@
+import ScenesReducer from '../ScenesReducer';
+
+const MOCK_DESCRIPTOR = {};
+
+/**
+ * Simulate scenes transtion with changes of navigation states.
+ */
+function testTransition(states) {
+  let descriptors = states
+    .reduce((acc, state) => acc.concat(state), [])
+    .reduce((acc, key) => {
+      acc[key] = MOCK_DESCRIPTOR;
+      return acc;
+    }, {});
+  const routes = states.map(keys => ({
+    index: 0,
+    routes: keys.map(key => ({ key, routeName: '' })),
+    isTransitioning: false,
+  }));
+
+  let scenes = [];
+  let prevState = null;
+  routes.forEach(nextState => {
+    scenes = ScenesReducer(scenes, nextState, prevState, descriptors);
+    prevState = nextState;
+  });
+
+  return scenes;
+}
+
+describe('ScenesReducer', () => {
+  it('gets initial scenes', () => {
+    const scenes = testTransition([['1', '2']]);
+
+    expect(scenes).toEqual([
+      {
+        index: 0,
+        isActive: true,
+        isStale: false,
+        descriptor: MOCK_DESCRIPTOR,
+        key: 'scene_1',
+        route: {
+          key: '1',
+          routeName: '',
+        },
+      },
+      {
+        index: 1,
+        isActive: false,
+        isStale: false,
+        descriptor: MOCK_DESCRIPTOR,
+        key: 'scene_2',
+        route: {
+          key: '2',
+          routeName: '',
+        },
+      },
+    ]);
+  });
+
+  it('pushes new scenes', () => {
+    // Transition from ['1', '2'] to ['1', '2', '3'].
+    const scenes = testTransition([['1', '2'], ['1', '2', '3']]);
+
+    expect(scenes).toEqual([
+      {
+        index: 0,
+        isActive: true,
+        isStale: false,
+        descriptor: MOCK_DESCRIPTOR,
+        key: 'scene_1',
+        route: {
+          key: '1',
+          routeName: '',
+        },
+      },
+      {
+        index: 1,
+        isActive: false,
+        isStale: false,
+        descriptor: MOCK_DESCRIPTOR,
+        key: 'scene_2',
+        route: {
+          key: '2',
+          routeName: '',
+        },
+      },
+      {
+        index: 2,
+        isActive: false,
+        isStale: false,
+        descriptor: MOCK_DESCRIPTOR,
+        key: 'scene_3',
+        route: {
+          key: '3',
+          routeName: '',
+        },
+      },
+    ]);
+  });
+
+  it('gets active scene when index changes', () => {
+    const state1 = {
+      index: 0,
+      routes: [{ key: '1', routeName: '' }, { key: '2', routeName: '' }],
+      isTransitioning: false,
+    };
+
+    const state2 = {
+      index: 1,
+      routes: [{ key: '1', routeName: '' }, { key: '2', routeName: '' }],
+      isTransitioning: false,
+    };
+
+    const scenes1 = ScenesReducer([], state1, null);
+    const scenes2 = ScenesReducer(scenes1, state2, state1);
+    const route = scenes2.find(scene => scene.isActive).route;
+    expect(route).toEqual({ key: '2', routeName: '' });
+  });
+
+  it('gets same scenes', () => {
+    const state1 = {
+      index: 0,
+      routes: [{ key: '1', routeName: '' }, { key: '2', routeName: '' }],
+      isTransitioning: false,
+    };
+
+    const state2 = {
+      index: 0,
+      routes: [{ key: '1', routeName: '' }, { key: '2', routeName: '' }],
+      isTransitioning: false,
+    };
+
+    const scenes1 = ScenesReducer([], state1, null);
+    const scenes2 = ScenesReducer(scenes1, state2, state1);
+    expect(scenes1).toBe(scenes2);
+  });
+
+  it('gets different scenes when keys are different', () => {
+    const state1 = {
+      index: 0,
+      routes: [{ key: '1', routeName: '' }, { key: '2', routeName: '' }],
+      isTransitioning: false,
+    };
+
+    const state2 = {
+      index: 0,
+      routes: [{ key: '2', routeName: '' }, { key: '1', routeName: '' }],
+      isTransitioning: false,
+    };
+
+    const descriptors = { 1: jest.mock(), 2: jest.mock() };
+
+    const scenes1 = ScenesReducer([], state1, null, descriptors);
+    const scenes2 = ScenesReducer(scenes1, state2, state1, descriptors);
+    expect(scenes1).not.toBe(scenes2);
+  });
+
+  it('gets different scenes when routes are different', () => {
+    const state1 = {
+      index: 0,
+      routes: [
+        { key: '1', x: 1, routeName: '' },
+        { key: '2', x: 2, routeName: '' },
+      ],
+      isTransitioning: false,
+    };
+
+    const state2 = {
+      index: 0,
+      routes: [
+        { key: '1', x: 3, routeName: '' },
+        { key: '2', x: 4, routeName: '' },
+      ],
+      isTransitioning: false,
+    };
+
+    const descriptors = { 1: MOCK_DESCRIPTOR, 2: MOCK_DESCRIPTOR };
+
+    const scenes1 = ScenesReducer([], state1, null, descriptors);
+    const scenes2 = ScenesReducer(scenes1, state2, state1, descriptors);
+    expect(scenes1).not.toBe(scenes2);
+  });
+
+  it('gets different scenes when state index changes', () => {
+    const state1 = {
+      index: 0,
+      routes: [
+        { key: '1', x: 1, routeName: '' },
+        { key: '2', x: 2, routeName: '' },
+      ],
+      isTransitioning: false,
+    };
+
+    const state2 = {
+      index: 1,
+      routes: [
+        { key: '1', x: 1, routeName: '' },
+        { key: '2', x: 2, routeName: '' },
+      ],
+      isTransitioning: false,
+    };
+
+    const descriptors = { 1: MOCK_DESCRIPTOR, 2: MOCK_DESCRIPTOR };
+    const scenes1 = ScenesReducer([], state1, null, descriptors);
+    const scenes2 = ScenesReducer(scenes1, state2, state1, descriptors);
+    expect(scenes1).not.toBe(scenes2);
+  });
+
+  it('pops scenes', () => {
+    // Transition from ['1', '2', '3'] to ['1', '2'].
+    const scenes = testTransition([['1', '2', '3'], ['1', '2']]);
+
+    expect(scenes).toEqual([
+      {
+        index: 0,
+        isActive: true,
+        isStale: false,
+        descriptor: MOCK_DESCRIPTOR,
+        key: 'scene_1',
+        route: {
+          key: '1',
+          routeName: '',
+        },
+      },
+      {
+        index: 1,
+        isActive: false,
+        isStale: false,
+        descriptor: MOCK_DESCRIPTOR,
+        key: 'scene_2',
+        route: {
+          key: '2',
+          routeName: '',
+        },
+      },
+      {
+        index: 2,
+        isActive: false,
+        isStale: true,
+        descriptor: MOCK_DESCRIPTOR,
+        key: 'scene_3',
+        route: {
+          key: '3',
+          routeName: '',
+        },
+      },
+    ]);
+  });
+
+  it('replaces scenes', () => {
+    const scenes = testTransition([['1', '2'], ['3']]);
+
+    expect(scenes).toEqual([
+      {
+        index: 0,
+        isActive: false,
+        isStale: true,
+        descriptor: MOCK_DESCRIPTOR,
+        key: 'scene_1',
+        route: {
+          key: '1',
+          routeName: '',
+        },
+      },
+      {
+        index: 0,
+        isActive: true,
+        isStale: false,
+        descriptor: MOCK_DESCRIPTOR,
+        key: 'scene_3',
+        route: {
+          key: '3',
+          routeName: '',
+        },
+      },
+      {
+        index: 1,
+        isActive: false,
+        isStale: true,
+        descriptor: MOCK_DESCRIPTOR,
+        key: 'scene_2',
+        route: {
+          key: '2',
+          routeName: '',
+        },
+      },
+    ]);
+  });
+
+  it('revives scenes', () => {
+    const scenes = testTransition([['1', '2'], ['3'], ['2']]);
+
+    expect(scenes).toEqual([
+      {
+        index: 0,
+        isActive: false,
+        isStale: true,
+        descriptor: MOCK_DESCRIPTOR,
+        key: 'scene_1',
+        route: {
+          key: '1',
+          routeName: '',
+        },
+      },
+      {
+        index: 0,
+        isActive: true,
+        isStale: false,
+        descriptor: MOCK_DESCRIPTOR,
+        key: 'scene_2',
+        route: {
+          key: '2',
+          routeName: '',
+        },
+      },
+      {
+        index: 0,
+        isActive: false,
+        isStale: true,
+        descriptor: MOCK_DESCRIPTOR,
+        key: 'scene_3',
+        route: {
+          key: '3',
+          routeName: '',
+        },
+      },
+    ]);
+  });
+});