Make mock links mock parameter readonly (#2284)

* Make mock links mock parameter readonly

Since mocks are not modified at runtime, allow readonly mock lists

* Changelog update

Changelog.md

@@ -27,6 +27,8 @@
 - Allow a custom `cache` object to be passed into the test-utils
   `MockedProvider`.  <br/>
   [@palmfjord](https://github.com/palmfjord) in [#2254](https://github.com/apollographql/react-apollo/pull/2254)
+- Make the `MockedProvider` `mocks` prop read only.  <br/>
+  [@amacleay](https://github.com/amacleay) in [#2284](https://github.com/apollographql/react-apollo/pull/2284)
 
 ## 2.1.11 (August 9, 2018)
 

src/test-links.ts

@@ -33,7 +33,7 @@ export class MockLink extends ApolloLink {
   public addTypename: Boolean = true;
   private mockedResponsesByKey: { [key: string]: MockedResponse[] } = {};
 
-  constructor(mockedResponses: MockedResponse[], addTypename: Boolean = true) {
+  constructor(mockedResponses: ReadonlyArray<MockedResponse>, addTypename: Boolean = true) {
     super();
     this.addTypename = addTypename;
     if (mockedResponses)

src/test-utils.tsx

@@ -9,7 +9,7 @@ import { ApolloCache } from 'apollo-cache';
 export * from './test-links';
 
 export interface MockedProviderProps<TSerializedCache = {}> {
-  mocks?: MockedResponse[];
+  mocks?: ReadonlyArray<MockedResponse>;
   addTypename?: boolean;
   defaultOptions?: DefaultOptions;
   cache?: ApolloCache<TSerializedCache>;

test/test-utils.test.tsx

@@ -6,6 +6,7 @@ import gql from 'graphql-tag';
 
 import { graphql, ChildProps } from '../src';
 import { MockedProvider, mockSingleLink } from '../src/test-utils';
+import { MockedResponse } from '../src/test-links';
 import { DocumentNode } from 'graphql';
 
 const variables = {
@@ -53,7 +54,7 @@ const withUser = graphql<Variables, Data, Variables>(query, {
   }),
 });
 
-const mocks = [
+const mocks: ReadonlyArray<MockedResponse> = [
   {
     request: {
       query,