DropIndex By Index Name Implementation #1090

Formatting Changes in catalog.cpp and catalog.h
Fix drop_test.cpp by applying EXPECT_EQ into proper transactions and removing EXPECT_EQ where it wasn't required. @poojanilangekar did the changes. I don't understand why the formatting changes keep on happening.
Solves #285

Author: dasdipanjan04

src/catalog/catalog.cpp

@@ -377,6 +377,7 @@ ResultType Catalog::CreateIndex(const std::string &database_name,
 
   LOG_TRACE("Trying to create index %s for table %s", index_name.c_str(),
             table_name.c_str());
+
   // check if database exists
   auto database_object =
       DatabaseCatalog::GetInstance()->GetDatabaseObject(database_name, txn);
@@ -392,9 +393,11 @@ ResultType Catalog::CreateIndex(const std::string &database_name,
 
   IndexConstraintType index_constraint =
       unique_keys ? IndexConstraintType::UNIQUE : IndexConstraintType::DEFAULT;
+
   ResultType success = CreateIndex(
       database_object->GetDatabaseOid(), table_object->GetTableOid(), key_attrs,
       index_name, index_type, index_constraint, unique_keys, txn);
+
   return success;
 }
 

src/include/catalog/catalog.h

@@ -176,8 +176,6 @@ class Catalog {
   std::shared_ptr<TableCatalogObject> GetTableObject(
       oid_t database_oid, oid_t table_oid,
       concurrency::TransactionContext *txn);
-
-
   //===--------------------------------------------------------------------===//
   // DEPRECATED FUNCTIONS
   //===--------------------------------------------------------------------===//

test/executor/drop_test.cpp

@@ -260,13 +260,8 @@ TEST_F(DropTests, DroppingIndexByName) {
   txn_manager.CommitTransaction(txn);
 
   txn = txn_manager.BeginTransaction();
-  auto index_catalog = catalog::IndexCatalog::GetInstance()->GetIndexObject(
-              index_name1, txn);
   // Check the effect of drop
   // Most major check in this test case
-  EXPECT_EQ(catalog::IndexCatalog::GetInstance()->GetIndexObject(
-                index_name1, txn), index_catalog);
-
   // Now dropping the index using the DropIndex functionality
   catalog->DropIndex(index_name1,txn);
   EXPECT_EQ(catalog::IndexCatalog::GetInstance()->GetIndexObject(
@@ -275,6 +270,11 @@ TEST_F(DropTests, DroppingIndexByName) {
 
   // Drop the table just created
   txn = txn_manager.BeginTransaction();
+  // Check the effect of drop index
+  EXPECT_EQ(catalog::IndexCatalog::GetInstance()->GetIndexObject(
+                index_name1, txn), nullptr);
+
+  // Now dropping the table
   catalog->DropTable(TEST_DB_NAME, "department_table_01", txn);
   txn_manager.CommitTransaction(txn);