test_runner: before and after each hooks

Author: MoLow

lib/internal/test_runner/harness.js

@@ -170,8 +170,20 @@ function runInParentContext(Factory) {
   return cb;
 }
 
+function afterEach(fn, options) {
+  const parent = testResources.get(executionAsyncId()) || setup(root);
+  parent.createBeforeEachHook(fn, options);
+
+}
+function beforeEach(fn, options) {
+  const parent = testResources.get(executionAsyncId()) || setup(root);
+  parent.createBeforeEachHook(fn, options);
+}
+
 module.exports = {
   test: FunctionPrototypeBind(test, root),
   describe: runInParentContext(Suite),
   it: runInParentContext(ItTest),
+  afterEach,
+  beforeEach,
 };

lib/internal/test_runner/test.js

@@ -47,6 +47,10 @@ class TestContext {
     this.#test = test;
   }
 
+  get name() {
+    return this.#test.name;
+  }
+
   diagnostic(message) {
     this.#test.diagnostic(message);
   }
@@ -69,6 +73,14 @@ class TestContext {
 
     return subtest.start();
   }
+
+  beforeEach(fn, options) {
+    this.#test.createBeforeEachHook(fn, options);
+  }
+
+  afterEach(fn, options) {
+    this.#test.createAfterEachHook(fn, options);
+  }
 }
 
 class Test extends AsyncResource {
@@ -140,6 +152,8 @@ class Test extends AsyncResource {
     this.pendingSubtests = [];
     this.readySubtests = new SafeMap();
     this.subtests = [];
+    this.beforeEachHooks = [];
+    this.afterEachHooks = [];
     this.waitingOn = 0;
     this.finished = false;
   }
@@ -242,6 +256,18 @@ class Test extends AsyncResource {
     return test;
   }
 
+  createBeforeEachHook(fn, options) {
+    const hook = new TestHook(fn, options);
+    ArrayPrototypePush(this.beforeEachHooks, hook);
+    return hook;
+  }
+
+  createAfterEachHook(fn, options) {
+    const hook = new TestHook(fn, options);
+    ArrayPrototypePush(this.afterEachHooks, hook);
+    return hook;
+  }
+
   cancel() {
     if (this.endTime !== null) {
       return;
@@ -253,6 +279,7 @@ class Test extends AsyncResource {
         kCancelledByParent
       )
     );
+    this.startTime = this.startTime || this.endTime; // if a test was canceled before it was started, e.g inside a hook
     this.cancelled = true;
   }
 
@@ -309,12 +336,24 @@ class Test extends AsyncResource {
     return { ctx, args: [ctx] };
   }
 
-  async run() {
-    this.parent.activeSubtests++;
+  async #runHooks(hooks) {
+    await ArrayPrototypeReduce(hooks, async (prev, hook) => {
+      await prev;
+      await hook.run(this.getRunArgs());
+    }, PromiseResolve()); 
+  }
+
+  async run(...runArgs) {
+    if (this.parent !== null) {
+      this.parent.activeSubtests++;
+    }
+    if (this.parent?.beforeEachHooks.length > 0) {
+      await this.#runHooks(this.parent.beforeEachHooks);
+    }
     this.startTime = hrtime();
 
     try {
-      const { args, ctx } = this.getRunArgs();
+      const { args, ctx } = ReflectApply(this.getRunArgs, this, runArgs);
       ArrayPrototypeUnshift(args, this.fn, ctx); // Note that if it's not OK to mutate args, we need to first clone it.
 
       if (this.fn.length === args.length - 1) {
@@ -347,9 +386,13 @@ class Test extends AsyncResource {
       }
     }
 
+    if (this.parent?.afterEachHooks.length > 0) {
+      await this.#runHooks(this.parent.afterEachHooks);
+    }
+
     // Clean up the test. Then, try to report the results and execute any
     // tests that were pending due to available concurrency.
-    this.postRun();
+    await this.postRun();
   }
 
   postRun() {
@@ -387,7 +430,7 @@ class Test extends AsyncResource {
       this.parent.activeSubtests--;
       this.parent.addReadySubtest(this);
       this.parent.processReadySubtestRange(false);
-      this.parent.processPendingSubtests();
+      return this.parent.processPendingSubtests();
     }
   }
 
@@ -447,10 +490,23 @@ class Test extends AsyncResource {
   }
 }
 
+class TestHook extends Test {
+  constructor(fn, options) { 
+    if (options === null || typeof options !== 'object') {
+      options = kEmptyObject;
+    }
+    super({ fn, ...options }); 
+  }
+  getRunArgs(testContext) {
+    return testContext;
+  }
+}
+
 class ItTest extends Test {
   constructor(opt) { super(opt); } // eslint-disable-line no-useless-constructor
   getRunArgs() {
-    return { ctx: {}, args: [] };
+    const ctx = new TestContext(this);
+    return { ctx, args: [] };
   }
 }
 class Suite extends Test {

lib/test.js

@@ -1,5 +1,5 @@
 'use strict';
-const { test, describe, it } = require('internal/test_runner/harness');
+const { test, describe, it, afterEach, beforeEach } = require('internal/test_runner/harness');
 const { emitExperimentalWarning } = require('internal/util');
 
 emitExperimentalWarning('The test runner');
@@ -8,3 +8,5 @@ module.exports = test;
 module.exports.test = test;
 module.exports.describe = describe;
 module.exports.it = it;
+module.exports.afterEach = afterEach;
+module.exports.beforeEach = beforeEach;

test/message/test_runner_desctibe_it.js

@@ -219,19 +219,6 @@ it('callback fail', (done) => {
   });
 });
 
-it('sync t is this in test', function() {
-  assert.deepStrictEqual(this, {});
-});
-
-it('async t is this in test', async function() {
-  assert.deepStrictEqual(this, {});
-});
-
-it('callback t is this in test', function(done) {
-  assert.deepStrictEqual(this, {});
-  done();
-});
-
 it('callback also returns a Promise', async (done) => {
   throw new Error('thrown from callback also returns a Promise');
 });

test/message/test_runner_desctibe_it.out

@@ -74,6 +74,9 @@ not ok 8 - sync throw fail
     *
     *
     *
+    *
+    *
+    *
   ...
 # Subtest: async skip pass
 ok 9 - async skip pass # SKIP
@@ -100,6 +103,9 @@ not ok 11 - async throw fail
     *
     *
     *
+    *
+    *
+    *
   ...
 # Subtest: async assertion fail
 not ok 12 - async assertion fail
@@ -108,9 +114,9 @@ not ok 12 - async assertion fail
   failureType: 'testCodeFailure'
   error: |-
     Expected values to be strictly equal:
-
+    
     true !== false
-
+    
   code: 'ERR_ASSERTION'
   stack: |-
     *
@@ -120,6 +126,9 @@ not ok 12 - async assertion fail
     *
     *
     *
+    *
+    *
+    *
   ...
 # Subtest: resolve pass
 ok 13 - resolve pass
@@ -141,6 +150,9 @@ not ok 14 - reject fail
     *
     *
     *
+    *
+    *
+    *
   ...
 # Subtest: unhandled rejection - passes but warns
 ok 15 - unhandled rejection - passes but warns
@@ -277,6 +289,9 @@ not ok 27 - sync skip option is false fail
     *
     *
     *
+    *
+    *
+    *
   ...
 # Subtest: <anonymous>
 ok 28 - <anonymous>
@@ -349,31 +364,16 @@ not ok 40 - callback fail
     *
     *
   ...
-# Subtest: sync t is this in test
-ok 41 - sync t is this in test
-  ---
-  duration_ms: *
-  ...
-# Subtest: async t is this in test
-ok 42 - async t is this in test
-  ---
-  duration_ms: *
-  ...
-# Subtest: callback t is this in test
-ok 43 - callback t is this in test
-  ---
-  duration_ms: *
-  ...
 # Subtest: callback also returns a Promise
-not ok 44 - callback also returns a Promise
+not ok 41 - callback also returns a Promise
   ---
   duration_ms: *
   failureType: 'callbackAndPromisePresent'
   error: 'passed a callback but also returned a Promise'
   code: 'ERR_TEST_FAILURE'
   ...
 # Subtest: callback throw
-not ok 45 - callback throw
+not ok 42 - callback throw
   ---
   duration_ms: *
   failureType: 'testCodeFailure'
@@ -387,9 +387,12 @@ not ok 45 - callback throw
     *
     *
     *
+    *
+    *
+    *
   ...
 # Subtest: callback called twice
-not ok 46 - callback called twice
+not ok 43 - callback called twice
   ---
   duration_ms: *
   failureType: 'multipleCallbackInvocations'
@@ -400,12 +403,12 @@ not ok 46 - callback called twice
     *
   ...
 # Subtest: callback called twice in different ticks
-ok 47 - callback called twice in different ticks
+ok 44 - callback called twice in different ticks
   ---
   duration_ms: *
   ...
 # Subtest: callback called twice in future tick
-not ok 48 - callback called twice in future tick
+not ok 45 - callback called twice in future tick
   ---
   duration_ms: *
   failureType: 'uncaughtException'
@@ -415,7 +418,7 @@ not ok 48 - callback called twice in future tick
     *
   ...
 # Subtest: callback async throw
-not ok 49 - callback async throw
+not ok 46 - callback async throw
   ---
   duration_ms: *
   failureType: 'uncaughtException'
@@ -425,20 +428,20 @@ not ok 49 - callback async throw
     *
   ...
 # Subtest: callback async throw after done
-ok 50 - callback async throw after done
+ok 47 - callback async throw after done
   ---
   duration_ms: *
   ...
 # Subtest: custom inspect symbol fail
-not ok 51 - custom inspect symbol fail
+not ok 48 - custom inspect symbol fail
   ---
   duration_ms: *
   failureType: 'testCodeFailure'
   error: 'customized'
   code: 'ERR_TEST_FAILURE'
   ...
 # Subtest: custom inspect symbol that throws fail
-not ok 52 - custom inspect symbol that throws fail
+not ok 49 - custom inspect symbol that throws fail
   ---
   duration_ms: *
   failureType: 'testCodeFailure'
@@ -482,15 +485,15 @@ not ok 52 - custom inspect symbol that throws fail
         *
       ...
     1..2
-not ok 53 - subtest sync throw fails
+not ok 50 - subtest sync throw fails
   ---
   duration_ms: *
   failureType: 'subtestsFailed'
   error: '2 subtests failed'
   code: 'ERR_TEST_FAILURE'
   ...
 # Subtest: invalid subtest fail
-not ok 54 - invalid subtest fail
+not ok 51 - invalid subtest fail
   ---
   duration_ms: *
   failureType: 'parentAlreadyFinished'
@@ -499,15 +502,15 @@ not ok 54 - invalid subtest fail
   stack: |-
     *
   ...
-1..54
+1..51
 # Warning: Test "unhandled rejection - passes but warns" generated asynchronous activity after the test ended. This activity created the error "Error: rejected from unhandled rejection fail" and would have caused the test to fail, but instead triggered an unhandledRejection event.
 # Warning: Test "async unhandled rejection - passes but warns" generated asynchronous activity after the test ended. This activity created the error "Error: rejected from async unhandled rejection fail" and would have caused the test to fail, but instead triggered an unhandledRejection event.
 # Warning: Test "immediate throw - passes but warns" generated asynchronous activity after the test ended. This activity created the error "Error: thrown from immediate throw fail" and would have caused the test to fail, but instead triggered an uncaughtException event.
 # Warning: Test "immediate reject - passes but warns" generated asynchronous activity after the test ended. This activity created the error "Error: rejected from immediate reject fail" and would have caused the test to fail, but instead triggered an unhandledRejection event.
 # Warning: Test "callback called twice in different ticks" generated asynchronous activity after the test ended. This activity created the error "Error [ERR_TEST_FAILURE]: callback invoked multiple times" and would have caused the test to fail, but instead triggered an uncaughtException event.
 # Warning: Test "callback async throw after done" generated asynchronous activity after the test ended. This activity created the error "Error: thrown from callback async throw after done" and would have caused the test to fail, but instead triggered an uncaughtException event.
-# tests 54
-# pass 23
+# tests 51
+# pass 20
 # fail 17
 # cancelled 0
 # skipped 9