fix(logger): enable sequential invocation in e2e test (#658)

* fix(logger): add invocation mode in e2e tests

* fix(logger): enable cold start e2e test

Author: Dmitry Balabanov

Diff for: packages/logger/tests/e2e/basicFeatures.middy.test.ts

@@ -72,7 +72,7 @@ describe(`logger E2E tests basic functionalities (middy) for runtime: ${runtime}
     logGroupName = outputs[STACK_OUTPUT_LOG_GROUP];
 
     // Invoke the function twice (one for cold start, another for warm start)
-    invocationLogs = await invokeFunction(functionName, 2);
+    invocationLogs = await invokeFunction(functionName, 2, 'SEQUENTIAL');
 
     console.log('logGroupName', logGroupName);
 
@@ -103,12 +103,11 @@ describe(`logger E2E tests basic functionalities (middy) for runtime: ${runtime}
       for (const message of coldStartLogMessages) {
         expect(message).toContain(`"cold_start":true`);
       }
-      // TODO: There is an issue with the way in which functions are invoked that always forces a cold start. (#590) 
-      // Link to tracked issue: https://github.com/awslabs/aws-lambda-powertools-typescript/issues/590
-      // const normalLogMessages = invocationLogs[1].getFunctionLogs(LEVEL.INFO);
-      // for (const message of normalLogMessages) {
-      //   expect(message).not.toContain(`"cold_start":true`);
-      // }
+
+      const normalLogMessages = invocationLogs[1].getFunctionLogs(LEVEL.INFO);
+      for (const message of normalLogMessages) {
+        expect(message).not.toContain(`"cold_start":true`);
+      }
     }, TEST_CASE_TIMEOUT);
   });
 

Diff for: packages/logger/tests/helpers/e2eUtils.ts

@@ -68,11 +68,10 @@ export const deployStack = async (stackArtifact: CloudFormationStackArtifact ):
   return result.outputs;
 };
 
-export const invokeFunction = async (functionName: string, times: number = 1): Promise<InvocationLogs[]> => {
+export const invokeFunction = async (functionName: string, times: number = 1, invocationMode: 'PARALLEL' | 'SEQUENTIAL' = 'PARALLEL'): Promise<InvocationLogs[]> => {
   const invocationLogs: InvocationLogs[] = [];
-  const promises = [];
-    
-  for (let i = 0; i < times; i++) {
+
+  const promiseFactory = () : Promise<void> => {
     const invokePromise = lambdaClient
       .invoke({
         FunctionName: functionName,
@@ -86,9 +85,15 @@ export const invokeFunction = async (functionName: string, times: number = 1): P
           throw new Error('No LogResult field returned in the response of Lambda invocation. This should not happen.');
         }
       });
-    promises.push(invokePromise);
-  }
-  await Promise.all(promises);
+
+    return invokePromise;
+  };
+  
+  const promiseFactories = Array.from({ length: times }, () => promiseFactory );
+  const invocation = invocationMode == 'PARALLEL'
+    ? Promise.all(promiseFactories.map(factory => factory()))
+    : chainPromises(promiseFactories);
+  await invocation;
 
   return invocationLogs; 
 };
@@ -106,3 +111,10 @@ export const destroyStack = async (app: App, stack: Stack): Promise<void> => {
     quiet: true,
   });
 };
+
+const chainPromises = async (promiseFactories: (() => Promise<void>)[]) : Promise<void> => {
+  let chain = Promise.resolve();
+  promiseFactories.forEach(factory => chain = chain.then(factory));
+
+  return chain;
+};