diff --git a/src/test/regress/citus_tests/query_generator/README.md b/src/test/regress/citus_tests/query_generator/README.md
index 3a52f245a..e804d035c 100644
--- a/src/test/regress/citus_tests/query_generator/README.md
+++ b/src/test/regress/citus_tests/query_generator/README.md
@@ -53,6 +53,7 @@ targetTables: <Table[]>
           name: <string>
           type: <string>
       distinctCopyCount: <int>
+      colocateWith: Optional<string>
 ```
 
 Explanation:
@@ -72,6 +73,7 @@ targetTables: "array of tables that will be used in generated queries"
           name: "name of column"
           type: "name of data type of column(only support 'int' now)"
       distinctCopyCount: "how many tables with the same configuration we should create(only by changing full name, still using the same name prefix)"
+      colocateWith: "colocated_with parameter"
 ```
 
 
diff --git a/src/test/regress/citus_tests/query_generator/bin/diff-checker.py b/src/test/regress/citus_tests/query_generator/bin/diff-checker.py
index 5bd2898a9..45df94971 100644
--- a/src/test/regress/citus_tests/query_generator/bin/diff-checker.py
+++ b/src/test/regress/citus_tests/query_generator/bin/diff-checker.py
@@ -73,6 +73,8 @@ def removeFailedQueryOutputFromFiles(distQueryOutFile, localQueryOutFile):
     acceptableErrors = [
         "ERROR:  complex joins are only supported when all distributed tables are co-located and joined on their distribution columns",
         "ERROR:  recursive complex joins are only supported when all distributed tables are co-located and joined on their distribution columns",
+        "ERROR:  cannot push down this subquery",
+        "ERROR:  cannot perform a lateral outer join when a distributed subquery references complex subqueries, CTEs or local tables",
     ]
     failedDistQueryIds = findFailedQueriesFromFile(distQueryOutFile, acceptableErrors)
     removeFailedQueryOutputFromFile(distQueryOutFile, failedDistQueryIds)
diff --git a/src/test/regress/citus_tests/query_generator/config/config.yaml b/src/test/regress/citus_tests/query_generator/config/config.yaml
index 10f5b4804..ee5bf04bf 100644
--- a/src/test/regress/citus_tests/query_generator/config/config.yaml
+++ b/src/test/regress/citus_tests/query_generator/config/config.yaml
@@ -36,18 +36,19 @@ targetTables:
           name: id
           type: int
       distinctCopyCount: 2
-  # - Table:
-  #     name: single_dist
-  #     citusType: SINGLE_SHARD_DISTRIBUTED
-  #     maxAllowedUseOnQuery: 10
-  #     rowCount: 10
-  #     nullRate: 0.1
-  #     duplicateRate: 0.1
-  #     columns:
-  #       - Column:
-  #         name: id
-  #         type: int
-  #     distinctCopyCount: 2
+  - Table:
+      name: single_dist
+      citusType: SINGLE_SHARD_DISTRIBUTED
+      maxAllowedUseOnQuery: 10
+      rowCount: 10
+      nullRate: 0.1
+      duplicateRate: 0.1
+      columns:
+        - Column:
+          name: id
+          type: int
+      distinctCopyCount: 2
+      colocateWith: none
   - Table:
       name: ref
       citusType: REFERENCE
diff --git a/src/test/regress/citus_tests/query_generator/config/config_parser.py b/src/test/regress/citus_tests/query_generator/config/config_parser.py
index 0b4f3837f..09a1438b7 100755
--- a/src/test/regress/citus_tests/query_generator/config/config_parser.py
+++ b/src/test/regress/citus_tests/query_generator/config/config_parser.py
@@ -49,6 +49,7 @@ def parseTable(targetTableDict):
         col = parseColumn(columnDict)
         columns.append(col)
     distinctCopyCount = targetTableDict["distinctCopyCount"]
+    colocateWith = targetTableDict.get("colocateWith", "default")
     return Table(
         name,
         citusType,
@@ -58,6 +59,7 @@ def parseTable(targetTableDict):
         duplicateRate,
         columns,
         distinctCopyCount,
+        colocateWith,
     )
 
 
diff --git a/src/test/regress/citus_tests/query_generator/data_gen.py b/src/test/regress/citus_tests/query_generator/data_gen.py
index a6ff5f232..d48b3ace4 100644
--- a/src/test/regress/citus_tests/query_generator/data_gen.py
+++ b/src/test/regress/citus_tests/query_generator/data_gen.py
@@ -35,51 +35,23 @@ def getTableData():
 
 def _genOverlappingData(tableName, startVal, rowCount):
     """returns string to fill table with [startVal,startVal+rowCount] range of integers"""
-    dataGenerationSql = ""
-    dataGenerationSql += "INSERT INTO " + tableName
-    dataGenerationSql += (
-        " SELECT i FROM generate_series("
-        + str(startVal)
-        + ","
-        + str(startVal + rowCount)
-        + ") i;"
-    )
-    return dataGenerationSql
+    return f"INSERT INTO {tableName} SELECT i FROM generate_series({startVal}, {startVal + rowCount}) i;"
 
 
 def _genNullData(tableName, nullCount):
     """returns string to fill table with NULLs"""
-    dataGenerationSql = ""
-    dataGenerationSql += "INSERT INTO " + tableName
-    dataGenerationSql += (
-        " SELECT NULL FROM generate_series(0," + str(nullCount) + ") i;"
+    return (
+        f"INSERT INTO {tableName} SELECT NULL FROM generate_series(0, {nullCount}) i;"
     )
-    return dataGenerationSql
 
 
 def _genDupData(tableName, dupRowCount):
     """returns string to fill table with duplicate integers which are fetched from given table"""
-    dataGenerationSql = ""
-    dataGenerationSql += "INSERT INTO " + tableName
-    dataGenerationSql += (
-        " SELECT * FROM "
-        + tableName
-        + " ORDER BY "
-        + getConfig().commonColName
-        + " LIMIT "
-        + str(dupRowCount)
-        + ";"
-    )
-    return dataGenerationSql
+    return f"INSERT INTO {tableName} SELECT * FROM {tableName} ORDER BY {getConfig().commonColName} LIMIT {dupRowCount};"
 
 
 def _genNonOverlappingData(tableName, startVal, tableIdx):
     """returns string to fill table with different integers for given table"""
     startVal = startVal + tableIdx * 20
     endVal = startVal + 20
-    dataGenerationSql = ""
-    dataGenerationSql += "INSERT INTO " + tableName
-    dataGenerationSql += (
-        " SELECT i FROM generate_series(" + str(startVal) + "," + str(endVal) + ") i;"
-    )
-    return dataGenerationSql
+    return f"INSERT INTO {tableName} SELECT i FROM generate_series({startVal}, {endVal}) i;"
diff --git a/src/test/regress/citus_tests/query_generator/ddl_gen.py b/src/test/regress/citus_tests/query_generator/ddl_gen.py
index 2e7d2e999..8d7b05950 100755
--- a/src/test/regress/citus_tests/query_generator/ddl_gen.py
+++ b/src/test/regress/citus_tests/query_generator/ddl_gen.py
@@ -17,10 +17,8 @@ def getTableDDLs():
 
 def _genTableDDL(table):
     ddl = ""
-    ddl += "DROP TABLE IF EXISTS " + table.name + ";"
-    ddl += "\n"
-
-    ddl += "CREATE TABLE " + table.name + "("
+    ddl += f"DROP TABLE IF EXISTS {table.name};\n"
+    ddl += f"CREATE TABLE {table.name}("
     for column in table.columns[:-1]:
         ddl += _genColumnDDL(column)
         ddl += ",\n"
@@ -29,28 +27,13 @@ def _genTableDDL(table):
     ddl += ");\n"
 
     if isTableHashDistributed(table):
-        ddl += (
-            "SELECT create_distributed_table("
-            + "'"
-            + table.name
-            + "','"
-            + getConfig().commonColName
-            + "'"
-            + ");"
-        )
-        ddl += "\n"
+        ddl += f"SELECT create_distributed_table('{table.name}','{getConfig().commonColName}', colocate_with=>'{table.colocateWith}');\n"
     if isTableSingleShardDistributed(table):
-        ddl += "SELECT create_distributed_table(" + "'" + table.name + "'" ",NULL);"
-        ddl += "\n"
+        ddl += f"SELECT create_distributed_table('{table.name}', NULL, colocate_with=>'{table.colocateWith}');\n"
     elif isTableReference(table):
-        ddl += "SELECT create_reference_table(" + "'" + table.name + "'" + ");"
-        ddl += "\n"
+        ddl += f"SELECT create_reference_table('{table.name}');\n"
     return ddl
 
 
 def _genColumnDDL(column):
-    ddl = ""
-    ddl += column.name
-    ddl += " "
-    ddl += column.type
-    return ddl
+    return f"{column.name} {column.type}"
diff --git a/src/test/regress/citus_tests/query_generator/node_defs.py b/src/test/regress/citus_tests/query_generator/node_defs.py
index 62135d177..3b8e2acfa 100755
--- a/src/test/regress/citus_tests/query_generator/node_defs.py
+++ b/src/test/regress/citus_tests/query_generator/node_defs.py
@@ -39,6 +39,7 @@ class Table:
         duplicateRate,
         columns,
         distinctCopyCount,
+        colocateWith,
     ):
         self.name = name
         self.citusType = citusType
@@ -48,6 +49,7 @@ class Table:
         self.duplicateRate = duplicateRate
         self.columns = columns
         self.distinctCopyCount = distinctCopyCount
+        self.colocateWith = colocateWith
 
 
 class Column:
diff --git a/src/test/regress/citus_tests/query_generator/query_gen.py b/src/test/regress/citus_tests/query_generator/query_gen.py
index e25525d29..bf5da3c05 100644
--- a/src/test/regress/citus_tests/query_generator/query_gen.py
+++ b/src/test/regress/citus_tests/query_generator/query_gen.py
@@ -114,15 +114,15 @@ class GeneratorContext:
     def randomCteName(self):
         """returns a randomly selected cte name"""
         randCteRef = random.randint(0, self.currentCteCount - 1)
-        return " cte_" + str(randCteRef)
+        return f" cte_{randCteRef}"
 
     def curAlias(self):
         """returns current alias name to be used for the current table"""
-        return " table_" + str(self.totalRteCount)
+        return f" table_{self.totalRteCount}"
 
     def curCteAlias(self):
         """returns current alias name to be used for the current cte"""
-        return " cte_" + str(self.currentCteCount)
+        return f" cte_{self.currentCteCount}"
 
     def hasAnyCte(self):
         """returns if context has any cte"""
@@ -153,7 +153,7 @@ class GeneratorContext:
         # do not enforce per table rte limit if we are inside cte
         if self.insideCte:
             rteName = random.choice(getAllTableNames())
-            return " " + rteName + " "
+            return f" {rteName} "
 
         while True:
             # keep trying to find random table by eliminating the ones which hit table limit
@@ -173,7 +173,7 @@ class GeneratorContext:
 
         # increment rte count for the table name
         self.perTableRtes[rteName] += 1
-        return " " + rteName + " "
+        return f" {rteName} "
 
 
 def newQuery():
@@ -206,8 +206,7 @@ def _genQuery(genCtx):
         and not genCtx.usedAvg
     ):
         genCtx.usedAvg = True
-        query += "SELECT "
-        query += "count(*), avg(avgsub." + getConfig().commonColName + ") FROM "
+        query += f"SELECT count(*), avg(avgsub.{getConfig().commonColName}) FROM "
         query += _genSubqueryRte(genCtx)
         query += " AS avgsub"
     else:
@@ -226,35 +225,24 @@ def _genQuery(genCtx):
 
 def _genOrderBy(genCtx):
     # 'ORDER BY' DistColName
-    query = ""
-    query += " ORDER BY "
-    query += getConfig().commonColName + " "
-    return query
+    return f" ORDER BY {getConfig().commonColName} "
 
 
 def _genLimit(genCtx):
     # 'LIMIT' 'random()'
-    query = ""
-    query += " LIMIT "
     (fromVal, toVal) = getConfig().limitRange
-    query += str(random.randint(fromVal, toVal))
-    return query
+    return f" LIMIT {random.randint(fromVal, toVal)}"
 
 
 def _genSelectExpr(genCtx):
     # 'SELECT' 'curAlias()' '.' DistColName
-    query = ""
-    query += " SELECT "
     commonColName = getConfig().commonColName
-    query += genCtx.curAlias() + "." + commonColName + " "
-
-    return query
+    return f" SELECT {genCtx.curAlias()}.{commonColName} "
 
 
 def _genFromExpr(genCtx):
     # 'FROM' (Rte JoinList JoinOp Rte Using || RteList) ['WHERE' 'nextRandomAlias()' '.' DistColName RestrictExpr]
-    query = ""
-    query += " FROM "
+    query = " FROM "
 
     if shouldSelectThatBranch():
         query += _genRte(genCtx)
@@ -267,8 +255,7 @@ def _genFromExpr(genCtx):
 
     alias = genCtx.removeLastAlias()
     if shouldSelectThatBranch():
-        query += " WHERE "
-        query += alias + "." + getConfig().commonColName
+        query += f" WHERE {alias}.{getConfig().commonColName}"
         query += _genRestrictExpr(genCtx)
     return query
 
@@ -353,9 +340,7 @@ def _genJoinList(genCtx):
 
 def _genUsing(genCtx):
     # 'USING' '(' DistColName ')'
-    query = ""
-    query += " USING (" + getConfig().commonColName + " ) "
-    return query
+    return f" USING ({getConfig().commonColName}) "
 
 
 def _genRte(genCtx):
@@ -392,7 +377,7 @@ def _genRte(genCtx):
         query += _genCteRte(genCtx)
     elif rteType == RTEType.VALUES:
         query += _genValuesRte(genCtx)
-        modifiedAlias = alias + "(" + getConfig().commonColName + ") "
+        modifiedAlias = f"{alias}({getConfig().commonColName}) "
     else:
         raise BaseException("unknown RTE type")
 
@@ -428,7 +413,5 @@ def _genCteRte(genCtx):
 
 def _genValuesRte(genCtx):
     # '( VALUES(random()) )'
-    query = ""
     (fromVal, toVal) = getConfig().dataRange
-    query += " ( VALUES(" + str(random.randint(fromVal, toVal)) + " ) ) "
-    return query
+    return f" ( VALUES({random.randint(fromVal, toVal)}) ) "
diff --git a/src/test/regress/citus_tests/query_generator/random_selections.py b/src/test/regress/citus_tests/query_generator/random_selections.py
index ee32c620a..47f55b3e5 100644
--- a/src/test/regress/citus_tests/query_generator/random_selections.py
+++ b/src/test/regress/citus_tests/query_generator/random_selections.py
@@ -25,7 +25,7 @@ def randomRteType():
 def randomJoinOp():
     """returns a randomly selected JoinOp given at config"""
     joinTypes = getConfig().targetJoinTypes
-    return " " + random.choice(joinTypes).name + " JOIN"
+    return f" {random.choice(joinTypes).name} JOIN"
 
 
 def randomRestrictOp():
@@ -42,4 +42,4 @@ def randomRestrictOp():
     else:
         raise BaseException("Unknown restrict op")
 
-    return " " + opText + " "
+    return f" {opText} "