From a43e1bb6eac69696f637c118edc87aa3eed995dc Mon Sep 17 00:00:00 2001
From: Simen Bekkhus <sbekkhus91@gmail.com>
Date: Sat, 11 Feb 2017 00:45:27 +0100
Subject: [PATCH] [WIP] Allow setting a test environment per file

---
 packages/jest-cli/src/runTest.js  | 127 +++++++++++++++++-------------
 packages/jest-config/src/index.js |   2 +
 2 files changed, 74 insertions(+), 55 deletions(-)

diff --git a/packages/jest-cli/src/runTest.js b/packages/jest-cli/src/runTest.js
index 19027e4f679a..aa5fb5a60004 100644
--- a/packages/jest-cli/src/runTest.js
+++ b/packages/jest-cli/src/runTest.js
@@ -13,7 +13,10 @@ import type {Path, Config} from 'types/Config';
 import type {TestResult} from 'types/TestResult';
 import type {Resolver} from 'types/Resolve';
 
+const fs = require('fs');
+const {getTestEnvironment} = require('jest-config');
 const BufferedConsole = require('./lib/BufferedConsole');
+const promisify = require('./lib/promisify');
 const {
   Console,
   NullConsole,
@@ -21,66 +24,80 @@ const {
 } = require('jest-util');
 const getConsoleOutput = require('./reporters/getConsoleOutput');
 
+const testEnvironmenPragmaRegex = /@testEnvironment\s+(.*)/;
+
 function runTest(path: Path, config: Config, resolver: Resolver) {
-  /* $FlowFixMe */
-  const TestEnvironment = require(config.testEnvironment);
-  /* $FlowFixMe */
-  const TestRunner = require(config.testRunner);
-  /* $FlowFixMe */
-  const ModuleLoader = require(config.moduleLoader || 'jest-runtime');
+  return promisify(fs.readFile)(path, 'utf8').then(data => {
+    let testEnvironment = config.testEnvironment;
+
+    const testEnvironmentPragma = data.match(testEnvironmenPragmaRegex);
 
-  const env = new TestEnvironment(config);
-  const TestConsole =
-    config.verbose
-      ? Console
-      : (config.silent
-        ? NullConsole
-        : BufferedConsole
+    if (testEnvironmentPragma && testEnvironmentPragma.length > 1) {
+      testEnvironment = getTestEnvironment(
+        Object.assign({}, config, {testEnvironment: testEnvironmentPragma[1]})
       );
-  const testConsole = new TestConsole(
-    config.useStderr ? process.stderr : process.stdout,
-    process.stderr,
-    (type, message) => getConsoleOutput(
-      config.rootDir,
-      !!config.verbose,
-      // 4 = the console call is burried 4 stack frames deep
-      BufferedConsole.write([], type, message, 4),
-    ),
-  );
-  setGlobal(env.global, 'console', testConsole);
-  const runtime = new ModuleLoader(config, env, resolver);
-  const start = Date.now();
-  return TestRunner(config, env, runtime, path)
-    .then((result: TestResult) => {
-      const testCount =
-        result.numPassingTests +
-        result.numFailingTests +
-        result.numPendingTests;
-      result.perfStats = {end: Date.now(), start};
-      result.testFilePath = path;
-      result.coverage = runtime.getAllCoverageInfo();
-      result.console = testConsole.getBuffer();
-      result.skipped = testCount === result.numPendingTests;
-      return result;
-    })
-    .then(
-      result => Promise.resolve().then(() => {
-        env.dispose();
-        if (config.logHeapUsage) {
-          if (global.gc) {
-            global.gc();
-          }
-          result.memoryUsage = process.memoryUsage().heapUsed;
-        }
+    }
+
+    /* $FlowFixMe */
+    const TestEnvironment = require(testEnvironment);
+    /* $FlowFixMe */
+    const TestRunner = require(config.testRunner);
+    /* $FlowFixMe */
+    const ModuleLoader = require(config.moduleLoader || 'jest-runtime');
 
-        // Delay the resolution to allow log messages to be output.
-        return new Promise(resolve => setImmediate(() => resolve(result)));
-      }),
-      err => Promise.resolve().then(() => {
-        env.dispose();
-        throw err;
-      }),
+    const env = new TestEnvironment(config);
+    const TestConsole =
+      config.verbose
+        ? Console
+        : (config.silent
+          ? NullConsole
+          : BufferedConsole
+        );
+    const testConsole = new TestConsole(
+      config.useStderr ? process.stderr : process.stdout,
+      process.stderr,
+      (type, message) => getConsoleOutput(
+        config.rootDir,
+        !!config.verbose,
+        // 4 = the console call is buried 4 stack frames deep
+        BufferedConsole.write([], type, message, 4),
+      ),
     );
+    setGlobal(env.global, 'console', testConsole);
+    const runtime = new ModuleLoader(config, env, resolver);
+    const start = Date.now();
+    return TestRunner(config, env, runtime, path)
+      .then((result: TestResult) => {
+        const testCount =
+          result.numPassingTests +
+          result.numFailingTests +
+          result.numPendingTests;
+        result.perfStats = {end: Date.now(), start};
+        result.testFilePath = path;
+        result.coverage = runtime.getAllCoverageInfo();
+        result.console = testConsole.getBuffer();
+        result.skipped = testCount === result.numPendingTests;
+        return result;
+      })
+      .then(
+        result => Promise.resolve().then(() => {
+          env.dispose();
+          if (config.logHeapUsage) {
+            if (global.gc) {
+              global.gc();
+            }
+            result.memoryUsage = process.memoryUsage().heapUsed;
+          }
+
+          // Delay the resolution to allow log messages to be output.
+          return new Promise(resolve => setImmediate(() => resolve(result)));
+        }),
+        err => Promise.resolve().then(() => {
+          env.dispose();
+          throw err;
+        }),
+      );
+  });
 }
 
 module.exports = runTest;
diff --git a/packages/jest-config/src/index.js b/packages/jest-config/src/index.js
index 624847bfe4fd..6f525094857e 100644
--- a/packages/jest-config/src/index.js
+++ b/packages/jest-config/src/index.js
@@ -15,6 +15,7 @@ const loadFromFile = require('./loadFromFile');
 const loadFromPackage = require('./loadFromPackage');
 const normalize = require('./normalize');
 const setFromArgv = require('./setFromArgv');
+const {getTestEnvironment} = require('./utils');
 
 const readConfig = (argv: Object, packageRoot: string) =>
   readRawConfig(argv, packageRoot)
@@ -48,6 +49,7 @@ const readRawConfig = (argv, root) => {
 };
 
 module.exports = {
+  getTestEnvironment,
   normalize,
   readConfig,
 };