Improve test_strptime_symmetry. NFC (#22152)

- Rename file to match test name
- Convert to C
- Capture detailed expectations

Author: sbc100

test/core/test_strptime_reentrant.c

@@ -5,6 +5,8 @@
  * found in the LICENSE file.
  */
 
+// glibc requires _XOPEN_SOURCE to be defined in order to get strptime.
+#define _XOPEN_SOURCE
 #include <time.h>
 #include <stdio.h>
 #include <string.h>
@@ -23,14 +25,14 @@ int main() {
       strptime("12", "%d", &tm) == NULL || strptime("Feb", "%b", &tm) == NULL ||
       strptime("13", "%M", &tm) == NULL || strptime("21", "%S", &tm) == NULL ||
       strptime("16", "%H", &tm) == NULL) {
-    printf("ERR: returned NULL");
+    printf("ERR: returned NULL\n");
     exit(EXIT_FAILURE);
   }
 
   if (tm.tm_sec != 21 || tm.tm_min != 13 || tm.tm_hour != 16 ||
       tm.tm_mday != 12 || tm.tm_mon != 1 || tm.tm_year != 107 ||
       tm.tm_wday != 1 || tm.tm_yday != 42) {
-    printf("ERR: unexpected tm content (1) - %d/%d/%d %d:%d:%d", tm.tm_mon + 1,
+    printf("ERR: unexpected tm content (1) - %d/%d/%d %d:%d:%d\n", tm.tm_mon + 1,
            tm.tm_mday, tm.tm_year + 1900, tm.tm_hour, tm.tm_min, tm.tm_sec);
     exit(EXIT_FAILURE);
   }
@@ -43,10 +45,10 @@ int main() {
   if (tm.tm_sec != 21 || tm.tm_min != 13 || tm.tm_hour != 16 ||
       tm.tm_mday != 8 || tm.tm_mon != 1 || tm.tm_year != 107 ||
       tm.tm_wday != 4 || tm.tm_yday != 38) {
-    printf("ERR: unexpected tm content (2) - %d/%d/%d %d:%d:%d", tm.tm_mon + 1,
+    printf("ERR: unexpected tm content (2) - %d/%d/%d %d:%d:%d\n", tm.tm_mon + 1,
            tm.tm_mday, tm.tm_year + 1900, tm.tm_hour, tm.tm_min, tm.tm_sec);
     exit(EXIT_FAILURE);
   }
 
-  printf("OK");
+  printf("OK\n");
 }

test/core/test_strptime_tm.c

@@ -5,6 +5,10 @@
  * found in the LICENSE file.
  */
 
+// glibc requires _XOPEN_SOURCE to be defined in order to get strptime.
+#define _XOPEN_SOURCE
+// glibc requires _DEFAULT_SOURCE to be defined in order to get tm_gmtoff.
+#define _DEFAULT_SOURCE
 #include <time.h>
 #include <stdio.h>
 #include <string.h>

test/other/test_strptime_symmetry.c

@@ -0,0 +1,72 @@
+// Copyright 2018 The Emscripten Authors.  All rights reserved.
+// Emscripten is available under two separate licenses, the MIT license and the
+// University of Illinois/NCSA Open Source License.  Both these licenses can be
+// found in the LICENSE file.
+
+// glibc requires _XOPEN_SOURCE to be defined in order to get strptime.
+#define _XOPEN_SOURCE
+#include <assert.h>
+#include <time.h>
+#include <string.h>
+#include <stdio.h>
+#include <stdbool.h>
+
+typedef struct tm TimeStruct;
+
+static void formatTM(TimeStruct const tm, char* buffer) {
+  sprintf(buffer, "%04d-%02d-%02dT%02d:%02d:%02d", tm.tm_year + 1900, tm.tm_mon + 1,
+    tm.tm_mday, tm.tm_hour, tm.tm_min, tm.tm_sec);
+}
+
+static bool isTimeStructEqual(const TimeStruct LHS, const TimeStruct RHS) {
+  return LHS.tm_year == RHS.tm_year && LHS.tm_mon == RHS.tm_mon && LHS.tm_mday == RHS.tm_mday &&
+         LHS.tm_hour == RHS.tm_hour && LHS.tm_min == RHS.tm_min && LHS.tm_sec == RHS.tm_sec;
+}
+
+bool parseAndCompare(const char* time, const char* expectedTime) {
+  TimeStruct tm;
+  memset(&tm, 0, sizeof(TimeStruct));
+  assert(strptime(time, "%FT%T%z", &tm));
+
+  char actualTime[256];
+  formatTM(tm, actualTime);
+  printf("input   : %s\n", time);
+  printf("expected: %s\n", expectedTime);
+  printf("actual  : %s\n", actualTime);
+  bool isEqual = strcmp(actualTime, expectedTime) == 0;
+  return isEqual;
+}
+
+// Ensure that the %c specifier can roundtrip. Meaning we use the same format
+// for strftime and strptime.
+bool roundTripCSpecifier() {
+  TimeStruct tm;
+  time_t t = time(NULL);
+  memcpy(&tm, localtime(&t), sizeof(TimeStruct));
+
+  char timeBuffer[256];
+  if (strftime(timeBuffer, sizeof(timeBuffer), "%c", &tm) == 0) {
+    printf("Failed to format current time\n");
+    return false;
+  }
+
+  TimeStruct newTm;
+  const char* lastParsed;
+  if ((lastParsed = strptime(timeBuffer, "%c", &newTm)) == NULL) {
+    printf("Failed to parse time string '%s'\n", timeBuffer);
+    return false;
+  }
+
+  return isTimeStructEqual(tm, newTm);
+}
+
+int main(int argc, char** argv) {
+  assert(parseAndCompare("2018-03-27T19:33:09+0000", "2018-03-27T19:33:09"));
+  assert(parseAndCompare("2018-03-27T19:33:09-0735", "2018-03-27T19:33:09"));
+  assert(parseAndCompare("2018-03-27T19:33:09+1043", "2018-03-27T19:33:09"));
+  assert(parseAndCompare("1900-01-01T00:00:00+0000", "1900-01-01T00:00:00"));
+  assert(parseAndCompare("2018-12-31T23:59:59+0000", "2018-12-31T23:59:59"));
+  assert(roundTripCSpecifier());
+  printf("TEST PASSED\n");
+  return 0;
+}

test/other/test_strptime_symmetry.out

@@ -0,0 +1,16 @@
+input   : 2018-03-27T19:33:09+0000
+expected: 2018-03-27T19:33:09
+actual  : 2018-03-27T19:33:09
+input   : 2018-03-27T19:33:09-0735
+expected: 2018-03-27T19:33:09
+actual  : 2018-03-27T19:33:09
+input   : 2018-03-27T19:33:09+1043
+expected: 2018-03-27T19:33:09
+actual  : 2018-03-27T19:33:09
+input   : 1900-01-01T00:00:00+0000
+expected: 1900-01-01T00:00:00
+actual  : 1900-01-01T00:00:00
+input   : 2018-12-31T23:59:59+0000
+expected: 2018-12-31T23:59:59
+actual  : 2018-12-31T23:59:59
+TEST PASSED

test/strptime_symmetry.cpp

@@ -2695,8 +2695,6 @@ def test_strptime_days(self):
     self.do_core_test('test_strptime_days.c')
 
   def test_strptime_reentrant(self):
-    # needs to flush stdio streams
-    self.set_setting('EXIT_RUNTIME')
     self.do_core_test('test_strptime_reentrant.c')
 
   @crossplatform

test/test_core.py

@@ -5884,7 +5884,7 @@ def test_strftime_zZ(self):
     self.do_runf('other/test_strftime_zZ.c', 'ok!')
 
   def test_strptime_symmetry(self):
-    self.do_runf('strptime_symmetry.cpp', 'TEST PASSED')
+    self.do_other_test('test_strptime_symmetry.c')
 
   @also_with_wasmfs
   def test_truncate_from_0(self):