diff --git a/.gitignore b/.gitignore
index a9f4ed5..7c4bc80 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,3 @@
 lib
-node_modules
\ No newline at end of file
+node_modules
+coverage
diff --git a/package.json b/package.json
index 23876f7..6f99485 100644
--- a/package.json
+++ b/package.json
@@ -14,6 +14,7 @@
   "scripts": {
     "build": "mkdir -p lib && babel ./src/index.js --plugins transform-object-assign --out-file ./lib/index.js",
     "test": "mocha --compilers js:babel-core/register --recursive",
+    "test:cov": "babel-node $(npm bin)/isparta cover $(npm bin)/_mocha -- --recursive",
     "prepublish": "npm run build"
   },
   "tags": [
@@ -32,6 +33,7 @@
     "babel-preset-es2015": "^6.1.2",
     "expect": "^1.13.0",
     "history": "^1.13.1",
+    "isparta": "^4.0.0",
     "mocha": "^2.3.4",
     "redux": "^3.0.4"
   }
diff --git a/test/index.js b/test/index.js
index 2aa051c..1981f2f 100644
--- a/test/index.js
+++ b/test/index.js
@@ -184,4 +184,53 @@ describe('syncReduxAndRouter', () => {
       changeId: 3
     });
   })
+
+  it('throws if "routing" key is missing with default selectRouteState', () => {
+    const store = createStore(combineReducers({
+      notRouting: routeReducer
+    }));
+    const history = createHistory();
+    expect(
+      () => syncReduxAndRouter(history, store)
+    ).toThrow(/Cannot sync router: route state does not exist/);
+  });
+
+  it('accepts custom selectRouterState', () => {
+    const store = createStore(combineReducers({
+      notRouting: routeReducer
+    }));
+    const history = createHistory();
+    syncReduxAndRouter(history, store, state => state.notRouting)
+    history.pushState(null, '/bar');
+    expect(store.getState().notRouting.path).toEqual('/bar');
+  });
+
+  it('returns unsubscribe to stop listening to history and store', () => {
+    const store = createStore(combineReducers({
+      routing: routeReducer
+    }));
+    const history = createHistory();
+    const unsubscribe = syncReduxAndRouter(history, store)
+
+    history.pushState(null, '/foo');
+    expect(store.getState().routing.path).toEqual('/foo');
+
+    store.dispatch(updatePath('/bar'));
+    expect(store.getState().routing).toEqual({
+      path: '/bar',
+      changeId: 2
+    });
+
+    unsubscribe();
+
+    history.pushState(null, '/foo');
+    expect(store.getState().routing.path).toEqual('/bar');
+
+    history.listenBefore(location => {
+      throw new Error()
+    });
+    expect(
+      () => store.dispatch(updatePath('/foo'))
+    ).toNotThrow();
+  });
 });