Add Async Test Environment APIs

Author: xfumihiro

packages/jest-runner/src/run_test.js

@@ -100,7 +100,11 @@ export default function runTest(
     mapCoverage: globalConfig.mapCoverage,
   });
   const start = Date.now();
-  return testFramework(globalConfig, config, environment, runtime, path)
+  return (environment.setup ? environment.setup() : (async () => ({}))())
+    .then(testSetup => {
+      setGlobal(environment.global, 'setup', testSetup);
+      return testFramework(globalConfig, config, environment, runtime, path);
+    })
     .then((result: TestResult) => {
       const testCount =
         result.numPassingTests +
@@ -117,22 +121,36 @@ export default function runTest(
     })
     .then(
       result =>
-        Promise.resolve().then(() => {
-          environment.dispose();
-          if (globalConfig.logHeapUsage) {
-            if (global.gc) {
-              global.gc();
+        Promise.resolve()
+          .then(
+            () =>
+              environment.teardown
+                ? environment.teardown()
+                : (async () => ({}))(),
+          )
+          .then(() => {
+            environment.dispose();
+            if (globalConfig.logHeapUsage) {
+              if (global.gc) {
+                global.gc();
+              }
+              result.memoryUsage = process.memoryUsage().heapUsed;
             }
-            result.memoryUsage = process.memoryUsage().heapUsed;
-          }
 
-          // Delay the resolution to allow log messages to be output.
-          return new Promise(resolve => setImmediate(() => resolve(result)));
-        }),
+            // Delay the resolution to allow log messages to be output.
+            return new Promise(resolve => setImmediate(() => resolve(result)));
+          }),
       err =>
-        Promise.resolve().then(() => {
-          environment.dispose();
-          throw err;
-        }),
+        Promise.resolve()
+          .then(
+            () =>
+              environment.teardown
+                ? environment.teardown()
+                : (async () => ({}))(),
+          )
+          .then(() => {
+            environment.dispose();
+            throw err;
+          }),
     );
 }

types/Environment.js

@@ -31,6 +31,8 @@ declare class $JestEnvironment {
   },
   testFilePath: string,
   moduleMocker: ModuleMocker,
+  setup(): Promise<Global>,
+  teardown(): Promise<void>,
 }
 
 export type Environment = $JestEnvironment;