test: add tests for getChildrenNavigationCache

packages/core/src/__tests__/getChildrenNavigationCache.test.js

@@ -0,0 +1,60 @@
+import getChildrenNavigationCache from '../getChildrenNavigationCache';
+
+it('should return empty table if navigation arg not provided', () => {
+  expect(getChildrenNavigationCache()._childrenNavigation).toBeUndefined();
+});
+
+it('should populate navigation._childrenNavigation as a side-effect', () => {
+  const navigation = {
+    state: {
+      routes: [{ key: 'one' }],
+    },
+  };
+  const result = getChildrenNavigationCache(navigation);
+  expect(result).toBeDefined();
+  expect(navigation._childrenNavigation).toBe(result);
+});
+
+it('should delete children cache keys that are no longer valid', () => {
+  const navigation = {
+    state: {
+      routes: [{ key: 'one' }, { key: 'two' }, { key: 'three' }],
+    },
+    _childrenNavigation: {
+      one: {},
+      two: {},
+      three: {},
+      four: {},
+    },
+  };
+
+  const result = getChildrenNavigationCache(navigation);
+  expect(result).toEqual({
+    one: {},
+    two: {},
+    three: {},
+  });
+});
+
+it('should not delete children cache keys if in transitioning state', () => {
+  const navigation = {
+    state: {
+      routes: [{ key: 'one' }, { key: 'two' }, { key: 'three' }],
+      isTransitioning: true,
+    },
+    _childrenNavigation: {
+      one: {},
+      two: {},
+      three: {},
+      four: {},
+    },
+  };
+
+  const result = getChildrenNavigationCache(navigation);
+  expect(result).toEqual({
+    one: {},
+    two: {},
+    three: {},
+    four: {},
+  });
+});