diff --git a/src/integration-test/java/com/commercetools/project/sync/CliRunnerIT.java b/src/integration-test/java/com/commercetools/project/sync/CliRunnerIT.java
index 95800826..722580b1 100644
--- a/src/integration-test/java/com/commercetools/project/sync/CliRunnerIT.java
+++ b/src/integration-test/java/com/commercetools/project/sync/CliRunnerIT.java
@@ -92,13 +92,17 @@
 import com.fasterxml.jackson.databind.node.ObjectNode;
 import io.vrap.rmf.base.client.ApiHttpResponse;
 import io.vrap.rmf.base.client.utils.json.JsonUtils;
+
+import java.time.Duration;
 import java.time.ZonedDateTime;
 import java.util.List;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.CompletionStage;
 import java.util.concurrent.ExecutionException;
+import java.util.concurrent.TimeUnit;
 import javax.annotation.Nonnull;
 import org.junit.jupiter.api.AfterAll;
+import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import uk.org.lidalia.slf4jext.Level;
@@ -359,12 +363,14 @@ static void tearDownSuite() {
   @Test
   void run_WithSyncAsArgumentWithAllArg_ShouldExecuteAllSyncers() {
     // test
+    assertEventually(Duration.ofSeconds(5), Duration.ofSeconds(5), () ->{
     CliRunner.of().run(new String[] {"-s", "all"}, createITSyncerFactory());
+        // assertions
+        assertAllSyncersLoggingEvents(1);
+        assertAllResourcesAreSyncedToTarget(CTP_TARGET_CLIENT);
+    }
+        );
 
-    // assertions
-    assertAllSyncersLoggingEvents(1);
-
-    assertAllResourcesAreSyncedToTarget(CTP_TARGET_CLIENT);
   }
 
   @Test
@@ -552,6 +558,7 @@ void run_WithUpdatedCustomer_ShouldSyncCustomersAndStoreLastSyncTimestampsAsCust
     // test
     CliRunner.of().run(new String[] {"-s", "customers"}, syncerFactory);
 
+    // assertions
     assertUpdatedCustomersAreSyncedCorrectly(CTP_SOURCE_CLIENT, CTP_TARGET_CLIENT);
 
     assertUpdatedCustomObjectTimestampAfterSync(
@@ -579,7 +586,7 @@ private ZonedDateTime getCustomObjectLastModifiedTime(
     final CustomObjectPagedQueryResponse lastSyncResult =
         fetchLastSyncCustomObject(targetClient, syncModuleName, runnerName);
 
-    return lastSyncResult.getResults().get(0).getLastModifiedAt();
+    return lastSyncResult.getResults().isEmpty() ? null : lastSyncResult.getResults().get(0).getLastModifiedAt();
   }
 
   private void updateCustomerSourceObject(@Nonnull final ProjectApiRoot sourceProjectClient) {
@@ -588,10 +595,8 @@ private void updateCustomerSourceObject(@Nonnull final ProjectApiRoot sourceProj
             .customers()
             .withKey(RESOURCE_KEY)
             .get()
-            .execute()
-            .thenApply(ApiHttpResponse::getBody)
-            .toCompletableFuture()
-            .join();
+            .executeBlocking()
+            .getBody();
 
     sourceProjectClient
         .customers()
@@ -603,9 +608,7 @@ private void updateCustomerSourceObject(@Nonnull final ProjectApiRoot sourceProj
                         CustomerSetFirstNameActionBuilder.of().firstName("testFirstName").build(),
                         CustomerSetLastNameActionBuilder.of().lastName("testLastName").build())
                     .version(customer.getVersion()))
-        .execute()
-        .toCompletableFuture()
-        .join();
+        .executeBlocking();
   }
 
   private void assertUpdatedCustomersAreSyncedCorrectly(
@@ -661,6 +664,25 @@ private void assertUpdatedCustomersAreSyncedCorrectly(
   }
 
   private void prepareDataForShoppingListSync(ProjectApiRoot sourceClient) {
+    QueryUtils.queryAll(
+        sourceClient.shoppingLists().get(),
+        shoppingLists -> {
+          CompletableFuture.allOf(
+              shoppingLists.stream()
+                           .map(
+                               shoppingList ->
+                                   sourceClient
+                                       .shoppingLists()
+                                       .delete(shoppingList)
+                                       .execute()
+                                       .thenApply(ApiHttpResponse::getBody))
+                           .map(CompletionStage::toCompletableFuture)
+                           .toArray(CompletableFuture[]::new))
+                           .join();
+        })
+              .toCompletableFuture()
+              .join();
+
     final ShoppingListDraft shoppingListDraft =
         ShoppingListDraftBuilder.of()
             .name(ofEnglish("shoppingList-name"))
@@ -1100,6 +1122,8 @@ private static void assertAllResourcesAreSyncedToTarget(
     assertShoppingListsAreSyncedCorrectly(targetClient);
   }
 
+  }
+
   public static void assertAllSyncersLoggingEvents(final int numberOfResources) {
 
     assertThat(cliRunnerTestLogger.getAllLoggingEvents())
diff --git a/src/main/java/com/commercetools/project/sync/Syncer.java b/src/main/java/com/commercetools/project/sync/Syncer.java
index 68385170..1bcd17a7 100644
--- a/src/main/java/com/commercetools/project/sync/Syncer.java
+++ b/src/main/java/com/commercetools/project/sync/Syncer.java
@@ -33,8 +33,6 @@
 import net.logstash.logback.marker.Markers;
 import org.slf4j.Logger;
 
-// This class compiles but not tested yet
-// TODO: Test class and adjust logic if needed
 /**
  * Base class of the syncer that handles syncing a resource from a source CTP project to a target
  * CTP project.
@@ -144,7 +142,7 @@ public CompletionStage<Void> sync(@Nullable final String runnerName, final boole
       syncStage =
           customObjectService
               .getCurrentCtpTimestamp(runnerName, syncModuleName)
-              .thenCompose(
+              .thenAccept(
                   currentCtpTimestamp ->
                       syncResourcesSinceLastSync(
                           sourceProjectKey, syncModuleName, runnerName, currentCtpTimestamp));
@@ -207,11 +205,11 @@ private CompletionStage<PagedQueryT> getQueryOfResourcesSinceLastSync(
   private PagedQueryT getQueryWithTimeBoundedPredicate(
       @Nonnull final ZonedDateTime lowerBound, @Nonnull final ZonedDateTime upperBound) {
 
+    final String queryPredicate = format(
+        "lastModifiedAt >= \"%s\" AND lastModifiedAt <= \"%s\"", lowerBound, upperBound);
     return (PagedQueryT)
         getQuery()
-            .withWhere("lastModifiedAt >= \":lower\" AND lastModifiedAt <= \":upper\"")
-            .withPredicateVar("lower", lowerBound)
-            .withPredicateVar("upper", upperBound);
+            .withWhere(queryPredicate);
   }
 
   @Nonnull