Correct buffer growth when formatting time (#367)

test/time-test.cc

@@ -0,0 +1,29 @@
+/*
+ Time formatting tests
+
+ Copyright (c) 2012 - 2016, Victor Zverovich
+ All rights reserved.
+
+ For the license information refer to format.h.
+ */
+
+#include "gmock/gmock.h"
+#include "fmt/time.h"
+
+TEST(TimeTest, Format) {
+  std::tm tm = std::tm();
+  tm.tm_year = 116;
+  tm.tm_mon  = 3;
+  tm.tm_mday = 25;
+  EXPECT_EQ("The date is 2016-04-25.",
+            fmt::format("The date is {:%Y-%m-%d}.", tm));
+}
+
+TEST(TimeTest, GrowBuffer) {
+  std::string s = "{:";
+  for (int i = 0; i < 30; ++i)
+    s += "%c";
+  s += "}\n";
+  std::time_t t = std::time(0);
+  fmt::format(s, *std::localtime(&t));
+}