[TD-2700]<fix>: fix incorrect generated time window.

src/os/CMakeLists.txt

@@ -10,3 +10,5 @@ ELSEIF (TD_WINDOWS)
 ENDIF ()
 
 ADD_SUBDIRECTORY(src/detail)
+ADD_SUBDIRECTORY(tests)
+

src/os/src/detail/osTime.c

@@ -502,8 +502,9 @@ int64_t taosTimeTruncate(int64_t t, const SInterval* pInterval, int32_t precisio
     }
 
     int64_t end = start + pInterval->interval - 1;
-    if (end < t) {
+    while(end < t) { // move forward to the correct time window
       start += pInterval->sliding;
+      end = start + pInterval->interval - 1;
     }
   }
 

src/os/tests/CMakeLists.txt

+CMAKE_MINIMUM_REQUIRED(VERSION 2.8)
+PROJECT(TDengine)
+
+FIND_PATH(HEADER_GTEST_INCLUDE_DIR gtest.h /usr/include/gtest /usr/local/include/gtest)
+FIND_LIBRARY(LIB_GTEST_STATIC_DIR libgtest.a /usr/lib/ /usr/local/lib)
+
+IF (HEADER_GTEST_INCLUDE_DIR AND LIB_GTEST_STATIC_DIR)
+    MESSAGE(STATUS "gTest library found, build unit test")
+
+    INCLUDE_DIRECTORIES(${HEADER_GTEST_INCLUDE_DIR})
+    AUX_SOURCE_DIRECTORY(${CMAKE_CURRENT_SOURCE_DIR} SOURCE_LIST)
+
+    ADD_EXECUTABLE(osTest ${SOURCE_LIST})
+    TARGET_LINK_LIBRARIES(osTest taos osdetail tutil common gtest pthread)
+ENDIF()
\ No newline at end of file

src/os/tests/test.cpp

+#include "os.h"
+#include <gtest/gtest.h>
+#include <cassert>
+#include <iostream>
+
+#include "taos.h"
+#include "tstoken.h"
+#include "tutil.h"
+
+int main(int argc, char** argv) {
+  testing::InitGoogleTest(&argc, argv);
+  return RUN_ALL_TESTS();
+}
+
+// test function in os module
+TEST(testCase, parse_time) {
+  taos_options(TSDB_OPTION_TIMEZONE, "GMT-8");
+  deltaToUtcInitOnce();
+
+  // window: 1500000001000, 1500002000000
+  // pQuery->interval: interval: 86400000, sliding:3600000
+  int64_t key = 1500000001000;
+  SInterval interval = {0};
+  interval.interval = 86400000;
+  interval.intervalUnit = 'd';
+  interval.sliding = 3600000;
+  interval.slidingUnit = 'h';
+
+  int64_t s = taosTimeTruncate(key, &interval, TSDB_TIME_PRECISION_MILLI);
+  ASSERT_TRUE(s + interval.interval >= key);
+}
+
+
+