Fix a Flaky Test in CalculatorAppTest (#1919)

Summary:
Pull Request resolved: #1919

## What
Modified CalculatorGame's `playFromSecretShare` method to return a dummy item with the publisherBreakdown field populated with dummy items as well, when the number of rows is zero.

Added test cases for empty intersection.

Added "long_running" and "heavyweight" tags to the test target, to reduce the probability of tests timing out.

## Why
A Calculator app test with random input shows as flaky. After investigation, it seems that the test fails when 1) UDP is turned on and 2) the intersection size = 0. In this case, both expected and actual results are dummy, but their formats are different, causing the test to fail.

The intersection size = 0 happens with a small probability, which is why the test only fails sometimes.

There are also some tests in the suite that requires longer than 600 seconds to run. So I added the tags to increase the timeout limit.

## Investigation process
https://docs.google.com/document/d/1raKj9_aaXUED5oCc48ICc5qyf_Anp0Fcy79ZhzV_YTM/edit#

Reviewed By: robotal

Differential Revision: D41241066

fbshipit-source-id: ba0ecbba728c8f357ab19dfd534bca09796d191e

Author: Hao Chen (Signals)

fbpcs/emp_games/lift/pcf2_calculator/CalculatorGame.h

@@ -63,7 +63,11 @@ class CalculatorGame : public fbpcf::frontend::MpcGame<schedulerId> {
     if (inputProcessor.getLiftGameProcessedData().numRows == 0) {
       XLOG(WARN) << "skipped calculating as numRows==0.";
       // skip game::run(), just output the default metrics.
-      return GroupedLiftMetrics().toJson();
+      return GroupedLiftMetrics(
+                 inputProcessor.getLiftGameProcessedData().numPartnerCohorts,
+                 inputProcessor.getLiftGameProcessedData()
+                     .numPublisherBreakdowns)
+          .toJson();
     }
 
     auto attributor = std::make_unique<Attributor<schedulerId>>(

fbpcs/emp_games/lift/pcf2_calculator/input_processing/CompactionBasedInputProcessor.h

@@ -64,7 +64,7 @@ class CompactionBasedInputProcessor : public IInputProcessor<schedulerId> {
     auto intersectionMap = getIntersectionMap(unionMap);
 
     if (intersectionMap.size() == 0) {
-      liftGameProcessedData_ = {};
+      liftGameProcessedData_.numRows = 0;
       return;
     }
 

fbpcs/emp_games/lift/pcf2_calculator/input_processing/LiftGameProcessedData_impl.h

@@ -141,7 +141,7 @@ LiftGameProcessedData<schedulerId>::readFromCSV(
           testReachShares));
 
   if (result.numRows == 0) {
-    return LiftGameProcessedData<schedulerId>{};
+    return result;
   }
 
   result.indexShares = transpose(indexShares);

fbpcs/emp_games/lift/pcf2_calculator/test/CalculatorAppTest.cpp

@@ -31,6 +31,9 @@
 
 namespace private_lift {
 
+constexpr uint64_t kDefaultNumPublisherBreakdowns = 2;
+constexpr uint64_t kDefaultNumCohorts = 4;
+
 template <int schedulerId>
 void runCalculatorApp(
     int myId,
@@ -356,7 +359,9 @@ GroupedLiftMetrics computeCorrectResults(
     bool usingCohorts) {
   // Calculate expected results with simple lift calculator
   LiftCalculator liftCalculator(
-      usingCohorts ? 4 : 0, usingPublisherBreakdowns ? 2 : 0, 0);
+      usingCohorts ? kDefaultNumCohorts : 0,
+      usingPublisherBreakdowns ? kDefaultNumPublisherBreakdowns : 0,
+      0);
   std::ifstream inFilePublisher{publisherPlaintextInputPath};
   std::ifstream inFilePartner{partnerPlaintextInputPath};
   int32_t tsOffset = 10;
@@ -386,12 +391,13 @@ void generateSyntheticData(
     int numRows,
     int numConversionsPerUser,
     bool generatePublisherBreakdowns,
-    bool useCohorts) {
+    bool useCohorts,
+    bool forceEmptyIntersection) {
   // Generate test input files with random data
   GenFakeData testDataGenerator;
   LiftFakeDataParams params;
   params.setNumRows(numRows)
-      .setOpportunityRate(0.5)
+      .setOpportunityRate(forceEmptyIntersection ? 0 : 0.5)
       .setTestRate(0.5)
       .setPurchaseRate(0.5)
       .setIncrementalityRate(0.0)
@@ -426,6 +432,7 @@ TEST_P(CalculatorAppTestFixture, TestCorrectnessRandomInput) {
       15,
       numConversionsPerUser,
       computePublisherBreakdowns,
+      false,
       false);
 
   GroupedLiftMetrics res = readInputFromSecretShares
@@ -462,6 +469,58 @@ TEST_P(CalculatorAppTestFixture, TestCorrectnessRandomInput) {
   EXPECT_EQ(expectedResult, res);
 }
 
+TEST_P(CalculatorAppTestFixture, TestCorrectnessRandomInputEmptyIntersection) {
+  // Run calculator app with test input
+  bool useTls = std::get<0>(GetParam());
+  bool useXorEncryption = std::get<1>(GetParam());
+  bool computePublisherBreakdowns = std::get<2>(GetParam());
+  bool readInputFromSecretShares = std::get<3>(GetParam());
+
+  // Generate test input files with random data
+  int numConversionsPerUser = 25;
+  generateSyntheticData(
+      publisherPlaintextInputPath_,
+      partnerPlaintextInputPath_,
+      15,
+      numConversionsPerUser,
+      computePublisherBreakdowns,
+      false,
+      true);
+
+  GroupedLiftMetrics res = readInputFromSecretShares
+      ? runUdpTest(
+            publisherPlaintextInputPath_,
+            partnerPlaintextInputPath_,
+            publisherGlobalParamsInputPath_,
+            partnerGlobalParamsInputPath_,
+            publisherSecretInputPath_,
+            partnerSecretInputPath_,
+            publisherOutputPath_,
+            partnerOutputPath_,
+            numConversionsPerUser,
+            computePublisherBreakdowns,
+            useTls,
+            useXorEncryption)
+      : runTest(
+            publisherPlaintextInputPath_,
+            partnerPlaintextInputPath_,
+            "",
+            publisherOutputPath_,
+            partnerOutputPath_,
+            numConversionsPerUser,
+            computePublisherBreakdowns,
+            useTls,
+            useXorEncryption);
+
+  GroupedLiftMetrics expectedResult = computeCorrectResults(
+      publisherPlaintextInputPath_,
+      partnerPlaintextInputPath_,
+      computePublisherBreakdowns,
+      false);
+
+  EXPECT_EQ(expectedResult, res);
+}
+
 TEST_P(CalculatorAppTestFixture, TestCorrectnessRandomInputAndCohort) {
   // Run calculator app with test input
   bool useTls = std::get<0>(GetParam());
@@ -478,7 +537,8 @@ TEST_P(CalculatorAppTestFixture, TestCorrectnessRandomInputAndCohort) {
       15,
       numConversionsPerUser,
       computePublisherBreakdowns,
-      true);
+      true,
+      false);
 
   GroupedLiftMetrics res = readInputFromSecretShares
       ? runUdpTest(
@@ -530,7 +590,8 @@ TEST_P(CalculatorAppTestFixture, TestWithEmptyInput) {
       0,
       numConversionsPerUser,
       computePublisherBreakdowns,
-      true);
+      true,
+      false);
 
   GroupedLiftMetrics res = readInputFromSecretShares
       ? runUdpTest(