Add typings tests to Store modules.

packages/@uppy/store-default/types/store-default-tests.ts

@@ -0,0 +1,9 @@
+import Uppy = require('@uppy/core');
+import DefaultStore = require('../');
+
+const store = DefaultStore();
+
+store.setState({ a: 'b' });
+store.getState();
+
+Uppy({ store });

packages/@uppy/store-redux/types/store-redux-tests.ts

@@ -0,0 +1,13 @@
+import { createStore, combineReducers } from 'redux';
+import Uppy = require('@uppy/core');
+import ReduxStore = require('../');
+
+const reducer = combineReducers({
+  uppy: ReduxStore.reducer
+});
+
+const store = ReduxStore({
+  store: createStore(reducer)
+});
+
+Uppy({ store });