Fix flaky tests on TransactionExecutor suite

The TransactionExecutor tests were mocking the global setTimeout and clearTimeout.
This mocks were conflicting with other calls to this api in the browser tests.
So, the calls to the set/clear were not being the expected in some situations.

Replace the global mock for injecting the functions resolve this issue in a less intrusive way.

Author: bigmontz

packages/core/src/internal/transaction-executor.ts

@@ -33,19 +33,30 @@ type Resolve<T> = (value: T | PromiseLike<T>) => void
 type Reject = (value: any) => void
 type Timeout = ReturnType<typeof setTimeout>
 
+interface Dependencies {
+  setTimeout: typeof setTimeout
+  clearTimeout: typeof clearTimeout
+}
+
 export class TransactionExecutor {
   private readonly _maxRetryTimeMs: number
   private readonly _initialRetryDelayMs: number
   private readonly _multiplier: number
   private readonly _jitterFactor: number
   private _inFlightTimeoutIds: Timeout[]
+  private readonly _setTimeout: typeof setTimeout
+  private readonly _clearTimeout: typeof clearTimeout
   public pipelineBegin: boolean
 
   constructor (
     maxRetryTimeMs?: number | null,
     initialRetryDelayMs?: number,
     multiplier?: number,
-    jitterFactor?: number
+    jitterFactor?: number,
+    dependencies: Dependencies = {
+      setTimeout,
+      clearTimeout
+    }
   ) {
     this._maxRetryTimeMs = _valueOrDefault(
       maxRetryTimeMs,
@@ -64,6 +75,9 @@ export class TransactionExecutor {
       DEFAULT_RETRY_DELAY_JITTER_FACTOR
     )
 
+    this._setTimeout = dependencies.setTimeout
+    this._clearTimeout = dependencies.clearTimeout
+
     this._inFlightTimeoutIds = []
     this.pipelineBegin = false
 
@@ -99,7 +113,7 @@ export class TransactionExecutor {
 
   close (): void {
     // cancel all existing timeouts to prevent further retries
-    this._inFlightTimeoutIds.forEach(timeoutId => clearTimeout(timeoutId))
+    this._inFlightTimeoutIds.forEach(timeoutId => this._clearTimeout(timeoutId))
     this._inFlightTimeoutIds = []
   }
 
@@ -119,7 +133,7 @@ export class TransactionExecutor {
 
     return new Promise<T>((resolve, reject) => {
       const nextRetryTime = this._computeDelayWithJitter(retryDelayMs)
-      const timeoutId = setTimeout(() => {
+      const timeoutId = this._setTimeout(() => {
         // filter out this timeoutId when time has come and function is being executed
         this._inFlightTimeoutIds = this._inFlightTimeoutIds.filter(
           id => id !== timeoutId

packages/neo4j-driver/test/internal/timers-util.js

@@ -15,47 +15,37 @@
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
+*/
+
+/**
+ * This is a liter mock which only creates mocked functions to work
+ * as timeouts.
  */
-class SetTimeoutMock {
+class TimeoutsMock {
   constructor () {
-    this._clearState()
+    this.clearState()
+    // bind it to be used as standalone functions
+    this.setTimeout = this.setTimeout.bind(this)
+    this.clearTimeout = this.clearTimeout.bind(this)
   }
 
-  install () {
-    this._originalSetTimeout = global.setTimeout
-    global.setTimeout = (code, delay) => {
-      if (!this._paused) {
-        code()
-        this.invocationDelays.push(delay)
-      }
-      return this._timeoutIdCounter++
-    }
-
-    this._originalClearTimeout = global.clearTimeout
-    global.clearTimeout = id => {
-      this.clearedTimeouts.push(id)
+  setTimeout (code, delay) {
+    if (!this._paused) {
+      code()
+      this.invocationDelays.push(delay)
     }
+    return this._timeoutIdCounter++
+  }
 
-    return this
+  clearTimeout (id) {
+    this.clearedTimeouts.push(id)
   }
 
   pause () {
     this._paused = true
   }
 
-  uninstall () {
-    global.setTimeout = this._originalSetTimeout
-    global.clearTimeout = this._originalClearTimeout
-    this._clearState()
-  }
-
-  setTimeoutOriginal (code, delay) {
-    return this._originalSetTimeout.call(null, code, delay)
-  }
-
-  _clearState () {
-    this._originalSetTimeout = null
-    this._originalClearTimeout = null
+  clearState () {
     this._paused = false
     this._timeoutIdCounter = 0
 
@@ -64,4 +54,6 @@ class SetTimeoutMock {
   }
 }
 
-export const setTimeoutMock = new SetTimeoutMock()
+export {
+  TimeoutsMock
+}