Generate screenshots of stories (cruise-automation#26)

This is an intermediate step before adding
https://github.com/reg-viz/reg-suit for screenshot tests.

I did a few other things in this PR:
- Moved inScreenshotTests files to the stories directory as we can now
  share code.
- When doing that I ran into an issue of eslint not liking the dot in
  `.storybook` imports, so I renamed that directory to `stories`. Bonus:
  this directory now gets properly linted!
- Also I had to add the root directory to webpack.config.js to be able
  to refer to `storybook/inScreenshotTests`.
- And when doing that I discovered that eslint-import-resolver-webpack
  didn’t pick up the root webpack.config.js properly in some cases, so
  I had to change .eslintrc.yml to .eslintrc.js so I could use __dirname
  to explicitly point to the right file.

Also I had to add the withScreenshots decorator to every story.

Test plan: tested locally; verified that it runs in CI.

.circleci/config.yml

@@ -1,3 +1,9 @@
+# Copyright (c) 2018-present, GM Cruise LLC
+#
+# This source code is licensed under the Apache License, Version 2.0,
+# found in the LICENSE file in the root directory of this source tree.
+# You may not use this file except in compliance with the License.
+
 # See https://circleci.com/docs/2.0/language-javascript/
 version: 2
 jobs:
@@ -44,6 +50,10 @@ jobs:
           name: "npm run build"
           command: npm run build
 
+      - run:
+          name: "npm run screenshot-ci"
+          command: npm run screenshot-ci
+
       - add_ssh_keys:
           fingerprints:
             - "d5:b8:7b:18:02:16:f1:90:6c:6d:34:b7:71:55:ae:b4"

.eslintignore

@@ -3,3 +3,4 @@ node_modules
 coverage
 build
 /flow-typed
+!.eslintrc.js

.eslintrc.js

@@ -0,0 +1,44 @@
+module.exports = {
+  env: { browser: true, node: true, jest: true },
+  extends: [
+    "eslint:recommended",
+    "plugin:jest/recommended",
+    "plugin:react/recommended",
+    "plugin:flowtype/recommended",
+    "plugin:import/recommended",
+    "problems",
+    "plugin:prettier/recommended",
+    "prettier/flowtype",
+    "prettier/react",
+  ],
+  plugins: ["jest", "import-order-alphabetical"],
+  parser: "babel-eslint",
+  settings: { "import/resolver": { webpack: { config: `${__dirname}/webpack.config.js` } } },
+  rules: {
+    curly: "error",
+    "prettier/prettier": "error",
+    "no-console": ["error", { allow: ["warn", "error"] }],
+    "no-unused-vars": ["error", { args: "none", varsIgnorePattern: "^_" }],
+    "flowtype/no-unused-expressions": "error",
+    "no-underscore-dangle": ["error", { allowAfterThis: true }],
+    "react/prop-types": "off", // We use Flow instead.
+    "no-useless-computed-key": "off", // https://github.com/facebook/flow/issues/380#issuecomment-224380551
+    yoda: "off", // https://github.com/RyanZim/eslint-config-problems/pull/1 and https://github.com/eslint/eslint/issues/10591
+    // Some good ones that people really should be adding to import/recommended:
+    "import/first": "error",
+    "import/no-self-import": "error",
+    "import/no-useless-path-segments": "error",
+    "import/no-mutable-exports": "error",
+    "import/newline-after-import": "error",
+    "import/no-duplicates": "error", // https://github.com/benmosher/eslint-plugin-import/issues/242#issuecomment-230118951
+    "no-duplicate-imports": "off", // False positives on flow type imports, so we use import/no-duplicates instead which handles them correctly.
+    // Group imports into two groups: packages and files. Sort alphabetically
+    // within those groups.
+    "import-order-alphabetical/order": [
+      "error",
+      { "newlines-between": "always", groups: [["builtin", "external"], ["internal", "parent", "sibling", "index"]] },
+    ],
+    // TODO(JP): Fix this instead of disabling it:
+    "import/no-named-as-default": "off",
+  },
+};

docs/src/jsx/withRanges.js

@@ -6,7 +6,7 @@
 
 import React from "react";
 
-import inScreenshotTests from "./inScreenshotTests";
+import inScreenshotTests from "stories/inScreenshotTests";
 
 export default (fn) => {
   class WithRange extends React.Component {