Allow tx timeout to be 0 and send it

Altering TestKit back end to treat exceptions on session.run and tx.run
as `DriverError`s

Author: robsdedude

packages/bolt-connection/src/bolt/request-message.js

@@ -256,7 +256,7 @@ export default class RequestMessage {
     if ( databaseContext.databaseName ) {
       dbContext.db = databaseContext.databaseName
     }
-    
+
     if ( databaseContext.impersonatedUser ) {
       dbContext.imp_user = databaseContext.impersonatedUser
     }
@@ -286,7 +286,7 @@ function buildTxMetadata (bookmark, txConfig, database, mode, impersonatedUser)
   if (!bookmark.isEmpty()) {
     metadata.bookmarks = bookmark.values()
   }
-  if (txConfig.timeout) {
+  if (txConfig.timeout != null) {
     metadata.tx_timeout = txConfig.timeout
   }
   if (txConfig.metadata) {

packages/core/src/internal/tx-config.ts

@@ -67,9 +67,6 @@ function extractTimeout(config: any): Integer | null {
   if (util.isObject(config) && (config.timeout || config.timeout === 0)) {
     util.assertNumberOrInteger(config.timeout, 'Transaction timeout')
     const timeout = int(config.timeout)
-    if (timeout.isZero()) {
-      throw newError('Transaction timeout should not be zero')
-    }
     if (timeout.isNegative()) {
       throw newError('Transaction timeout should not be negative')
     }

packages/testkit-backend/src/request-handlers.js

@@ -153,7 +153,14 @@ export function SessionRun (context, data, wire) {
   Promise.all(observers.map(obs => obs.completitionPromise()))
     .catch(_ => null)
     .then(_ => {
-      const result = session.run(cypher, params, { metadata, timeout })
+      let result
+      try {
+        result = session.run(cypher, params, { metadata, timeout })
+      } catch (e) {
+        console.log('got some err: ' + JSON.stringify(e))
+        wire.writeError(e)
+        return
+      }
       const resultObserver = new ResultObserver({ sessionId, result })
       const id = context.addResultObserver(resultObserver)
       wire.writeResponse('Result', { id })
@@ -261,7 +268,14 @@ export function RetryableNegative (context, data, wire) {
 export function SessionBeginTransaction (context, data, wire) {
   const { sessionId, txMeta: metadata, timeout } = data
   const session = context.getSession(sessionId)
-  const tx = session.beginTransaction({ metadata, timeout })
+  let tx
+  try {
+    tx = session.beginTransaction({ metadata, timeout })
+  } catch (e) {
+    console.log('got some err: ' + JSON.stringify(e))
+    wire.writeError(e)
+    return
+  }
   const id = context.addTx(tx, sessionId)
   wire.writeResponse('Transaction', { id })
 }