EXPLAIN: Initialize *before* checking specific cases

* Initialize *before* checking specific cases
* add basic tests for EXPLAIN

Parser/ParserWrapper.cpp

@@ -148,6 +148,8 @@ ParserWrapper::~ParserWrapper() {}
 
 void ParserWrapper::initExplainType(std::string query_string) {
   // sets explain_type_ and caches a trimmed actual_query_
+  explain_type_ = ParserWrapper::ExplainType::None;
+
   if (boost::istarts_with(query_string, calcite_explain_str)) {
     actual_query_ = boost::trim_copy(query_string.substr(calcite_explain_str.size()));
     ParserWrapper inner{actual_query_};
@@ -184,8 +186,6 @@ void ParserWrapper::initExplainType(std::string query_string) {
       explain_type_ = ExplainType::IR;
     }
   }
-
-  explain_type_ = ParserWrapper::ExplainType::None;
 }
 
 ExplainInfo ParserWrapper::getExplainInfo() const {

Tests/CMakeLists.txt

@@ -33,6 +33,7 @@ add_executable(JSONTest JSONTest.cpp)
 endif()
 add_executable(DataRecyclerTest DataRecyclerTest.cpp)
 add_executable(DataMgrTest DataMgrTest.cpp)
+add_executable(ExplainTest ExplainTest.cpp)
 
 if(ENABLE_CUDA)
   message(DEBUG "Tests CUDA_COMPILATION_ARCH: ${CUDA_COMPILATION_ARCH}")
@@ -240,6 +241,7 @@ if(NOT MSVC)
 target_link_libraries(JSONTest gtest Logger Shared)
 endif()
 target_link_libraries(DataMgrTest DataMgr ${THRIFT_HANDLER_TEST_LIBRARIES})
+target_link_libraries(ExplainTest ${THRIFT_HANDLER_TEST_LIBRARIES})
 
 
 if(NOT ${CMAKE_SYSTEM_NAME} STREQUAL "Darwin")
@@ -347,6 +349,7 @@ if(NOT MSVC)
 add_test(JSONTest JSONTest ${TEST_ARGS})
 endif()
 add_test(DataMgrTest DataMgrTest ${TEST_ARGS})
+add_test(ExplainTest ExplainTest ${TEST_ARGS})
 
 if(ENABLE_SYSTEM_TFS)
   add_test(SystemTableFunctionsTest SystemTableFunctionsTest ${TEST_ARGS})
@@ -470,6 +473,8 @@ if(NOT MSVC)
 endif()
 list(APPEND TEST_PROGRAMS
   DataMgrTest)
+list(APPEND TEST_PROGRAMS
+  ExplainTest)
 
 if(NOT MSVC)
   list(APPEND TEST_PROGRAMS

Tests/ExplainTest.cpp

@@ -0,0 +1,86 @@
+/*
+ * Copyright 2022 HEAVY.AI, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * @file ExplainTest.cpp
+ * @brief Test suite for EXPLAIN commands
+ */
+
+#include <gtest/gtest.h>
+
+#include "DBHandlerTestHelpers.h"
+#include "Shared/SysDefinitions.h"
+#include "TestHelpers.h"
+
+#ifndef BASE_PATH
+#define BASE_PATH "./tmp"
+#endif
+
+class ExplainTest : public DBHandlerTestFixture {
+ public:
+  void SetUp() override {
+    DBHandlerTestFixture::SetUp();
+    sql("drop table if exists table_trivial;");
+    sql("create table table_trivial (c1 integer);");
+  }
+
+  void TearDown() override {
+    sql("drop table if exists table_trivial;");
+    DBHandlerTestFixture::TearDown();
+  }
+
+ private:
+};
+
+TEST_F(ExplainTest, ExplainCmds) {
+  // Basic tests to simply validate that EXPLAIN can be run
+  //   and successfully accomplish simple parsing
+
+  // TODO: verify output as well ?
+
+  // EXPLAIN
+  ASSERT_NO_THROW(sql("EXPLAIN SELECT COUNT(*) FROM table_trivial;"));
+
+  // EXPLAIN OPTIMIZED
+  ASSERT_NO_THROW(sql("EXPLAIN OPTIMIZED SELECT COUNT(*) FROM table_trivial;"));
+
+  // EXPLAIN CALCITE
+  ASSERT_NO_THROW(sql("EXPLAIN CALCITE SELECT COUNT(*) FROM table_trivial;"));
+
+  // EXPLAIN PLAN
+  ASSERT_NO_THROW(sql("EXPLAIN PLAN SELECT COUNT(*) FROM table_trivial;"));
+
+  // After the "EXPLAIN PLAN" is stripped off the input and
+  //   the remainder sent to Calcite it should throw an exception
+  //   because "nonexistant_table_name" does not exist
+  EXPECT_THROW(sql("EXPLAIN PLAN SELECT COUNT(*) FROM nonexistant_table_name;"),
+               TOmniSciException);
+}
+
+int main(int argc, char** argv) {
+  TestHelpers::init_logger_stderr_only(argc, argv);
+  testing::InitGoogleTest(&argc, argv);
+  DBHandlerTestFixture::initTestArgs(argc, argv);
+
+  int err{0};
+  try {
+    testing::AddGlobalTestEnvironment(new DBHandlerTestEnvironment);
+    err = RUN_ALL_TESTS();
+  } catch (const std::exception& e) {
+    LOG(ERROR) << e.what();
+  }
+  return err;
+}