Add Jest tests and Prettier support (hound-search#343)

This commit adds support for Jest and writes a few simple tests as
proof. Adding a test is as easy as adding a file that ends in
`.test.js` next to the file you want to test. Any file that matches that
pattern should have access to Jest functions. The whole test suite can
be run with `npm run test`.

I also added support for Prettier. Running `npm run format`
should run Prettier on any staged changes. I thought about adding Husky
to automatically run Prettier as a pre-commit hook, but it seems as
though Husky requires git v2.13 which would require me upgrading Git.

I didn't add support for ESLint yet since I figured that may be a
slightly more involved conversation — Prettier seems to be generally
uncontroverical and is generally only slightly configurable, whereas
ESlint is highly configurable and behaves however we want it to.

.prettierignore

@@ -0,0 +1,3 @@
+ui/assets/js/JSXTransformer-0.12.2.js
+ui/assets/js/jquery-2.1.3.min.js
+ui/assets/js/react-0.12.2.min.js

.prettierrc

@@ -0,0 +1,3 @@
+{
+    "tabWidth": 4
+}

CONTRIBUTING.md

@@ -10,7 +10,7 @@ Once you're ready, open a [pull request](https://github.com/hound-search/hound/c
 your changes (you can read more about pull requests on GitHub [here](http://help.github.com/pull-requests/)).
 
 When you send a pull request, please be sure to include: 
-- unit tests that validate that your changes work as expected
+- unit tests that validate that your changes work as expected (both for Go and for JavaScript changes)
 - consice code comments (it can help to imagine that you're explaining your code to a total stranger)
 - an examples, if necessary.
 

Makefile

@@ -33,6 +33,7 @@ dev: ALL
 
 test:
 	go test github.com/hound-search/hound/...
+	npm test
 
 clean:
 	rm -rf .build node_modules

README.md

@@ -117,11 +117,19 @@ GOPATH=$(pwd) make -C src/github.com/hound-search/hound
 ### Testing
 
 There are an increasing number of tests in each of the packages in Hound. Please make sure these pass before uploading your Pull Request. You can run the tests with the following command.
+To run the entire test suite, use:
 
 ```
 make test
 ```
 
+If you want to just run the JavaScript test suite, use:
+```
+npm test
+```
+
+Any Go files that end in `_test.go` are assumed to be test files.  Similarly, any JavaScript files that ends in `.test.js` are automatically run by Jest, our test runner. Tests should live next to the files that they cover. [Check out Jest's docs](https://jestjs.io/docs/en/getting-started) for more details on writing Jest tests, and [check out Go's testing docs](https://golang.org/pkg/testing/) for more details on testing Go code.
+
 ### Working on the web UI
 
 Hound includes a web UI that is composed of several files (html, css, javascript, etc.). To make sure hound works seamlessly with the standard Go tools, these resources are all bundled inside of the `houndd` binary. Note that changes to the UI will result in local changes to the `ui/bindata.go` file. You must include these changes in your Pull Request.

jest.config.js

@@ -0,0 +1,188 @@
+// For a detailed explanation regarding each configuration property, visit:
+// https://jestjs.io/docs/en/configuration.html
+
+module.exports = {
+    // All imported modules in your tests should be mocked automatically
+    // automock: false,
+
+    // Stop running tests after `n` failures
+    // bail: 0,
+
+    // Respect "browser" field in package.json when resolving modules
+    // browser: false,
+
+    // The directory where Jest should store its cached dependency information
+    // cacheDirectory: "/tmp/jest_8hl",
+
+    // Automatically clear mock calls and instances between every test
+    clearMocks: true,
+
+    // Indicates whether the coverage information should be collected while executing the test
+    // collectCoverage: false,
+
+    // An array of glob patterns indicating a set of files for which coverage information should be collected
+    // collectCoverageFrom: undefined,
+
+    // The directory where Jest should output its coverage files
+    coverageDirectory: "coverage",
+
+    // An array of regexp pattern strings used to skip coverage collection
+    // coveragePathIgnorePatterns: [
+    //   "/node_modules/"
+    // ],
+
+    // A list of reporter names that Jest uses when writing coverage reports
+    // coverageReporters: [
+    //   "json",
+    //   "text",
+    //   "lcov",
+    //   "clover"
+    // ],
+
+    // An object that configures minimum threshold enforcement for coverage results
+    // coverageThreshold: undefined,
+
+    // A path to a custom dependency extractor
+    // dependencyExtractor: undefined,
+
+    // Make calling deprecated APIs throw helpful error messages
+    // errorOnDeprecated: false,
+
+    // Force coverage collection from ignored files using an array of glob patterns
+    // forceCoverageMatch: [],
+
+    // A path to a module which exports an async function that is triggered once before all test suites
+    // globalSetup: undefined,
+
+    // A path to a module which exports an async function that is triggered once after all test suites
+    // globalTeardown: undefined,
+
+    // A set of global variables that need to be available in all test environments
+    // globals: {},
+
+    // The maximum amount of workers used to run your tests. Can be specified as % or a number. E.g. maxWorkers: 10% will use 10% of your CPU amount + 1 as the maximum worker number. maxWorkers: 2 will use a maximum of 2 workers.
+    // maxWorkers: "50%",
+
+    // An array of directory names to be searched recursively up from the requiring module's location
+    // moduleDirectories: [
+    //   "node_modules"
+    // ],
+
+    // An array of file extensions your modules use
+    // moduleFileExtensions: [
+    //   "js",
+    //   "json",
+    //   "jsx",
+    //   "ts",
+    //   "tsx",
+    //   "node"
+    // ],
+
+    // A map from regular expressions to module names or to arrays of module names that allow to stub out resources with a single module
+    // moduleNameMapper: {},
+
+    // An array of regexp pattern strings, matched against all module paths before considered 'visible' to the module loader
+    // modulePathIgnorePatterns: [],
+
+    // Activates notifications for test results
+    // notify: false,
+
+    // An enum that specifies notification mode. Requires { notify: true }
+    // notifyMode: "failure-change",
+
+    // A preset that is used as a base for Jest's configuration
+    // preset: undefined,
+
+    // Run tests from one or more projects
+    // projects: undefined,
+
+    // Use this configuration option to add custom reporters to Jest
+    // reporters: undefined,
+
+    // Automatically reset mock state between every test
+    // resetMocks: false,
+
+    // Reset the module registry before running each individual test
+    // resetModules: false,
+
+    // A path to a custom resolver
+    // resolver: undefined,
+
+    // Automatically restore mock state between every test
+    // restoreMocks: false,
+
+    // The root directory that Jest should scan for tests and modules within
+    // rootDir: undefined,
+
+    // A list of paths to directories that Jest should use to search for files in
+    // roots: [
+    //   "<rootDir>"
+    // ],
+
+    // Allows you to use a custom runner instead of Jest's default test runner
+    // runner: "jest-runner",
+
+    // The paths to modules that run some code to configure or set up the testing environment before each test
+    // setupFiles: [],
+
+    // A list of paths to modules that run some code to configure or set up the testing framework before each test
+    // setupFilesAfterEnv: [],
+
+    // A list of paths to snapshot serializer modules Jest should use for snapshot testing
+    // snapshotSerializers: [],
+
+    // The test environment that will be used for testing
+    // testEnvironment: "jest-environment-jsdom",
+
+    // Options that will be passed to the testEnvironment
+    // testEnvironmentOptions: {},
+
+    // Adds a location field to test results
+    // testLocationInResults: false,
+
+    // The glob patterns Jest uses to detect test files
+    // testMatch: [
+    //   "**/__tests__/**/*.[jt]s?(x)",
+    //   "**/?(*.)+(spec|test).[tj]s?(x)"
+    // ],
+
+    // An array of regexp pattern strings that are matched against all test paths, matched tests are skipped
+    // testPathIgnorePatterns: [
+    //   "/node_modules/"
+    // ],
+
+    // The regexp pattern or array of patterns that Jest uses to detect test files
+    // testRegex: [],
+
+    // This option allows the use of a custom results processor
+    // testResultsProcessor: undefined,
+
+    // This option allows use of a custom test runner
+    // testRunner: "jasmine2",
+
+    // This option sets the URL for the jsdom environment. It is reflected in properties such as location.href
+    // testURL: "http://localhost",
+
+    // Setting this value to "fake" allows the use of fake timers for functions such as "setTimeout"
+    // timers: "real",
+
+    // A map from regular expressions to paths to transformers
+    // transform: undefined,
+
+    // An array of regexp pattern strings that are matched against all source file paths, matched files will skip transformation
+    // transformIgnorePatterns: [
+    //   "/node_modules/"
+    // ],
+
+    // An array of regexp pattern strings that are matched against all modules before the module loader will automatically return a mock for them
+    // unmockedModulePathPatterns: undefined,
+
+    // Indicates whether each individual test should be reported during the run
+    // verbose: undefined,
+
+    // An array of regexp patterns that are matched against all source file paths before re-running tests in watch mode
+    // watchPathIgnorePatterns: [],
+
+    // Whether to use watchman for file crawling
+    // watchman: true,
+};