Move test_count_digits to format-impl-test and disable gtest warnings (#1147)

* This translation unit includes `gtest.h` in which using something like `strncpy`

Suppress MSVC warnings from `gtest.h` included.

Warning sample:
fmt-master\test\gtest\gtest.h(2873,10): warning: 'strncpy' is deprecated: This function or variable may be unsafe. Consider using strncpy_s instead. To disable deprecation, use _CRT_SECURE_NO_WARNINGS. See online help for details. [-Wdeprecated-declarations]

* Moving `test_count_digits` to format-impl-test then count_digits<4>(internal::uintptr_t) shall not be exported

* retaining _CRT_SECURE_NO_WARNINGS always defined should be no harms.

test/custom-formatter-test.cc

@@ -5,6 +5,10 @@
 //
 // For the license information refer to format.h.
 
+#ifndef _CRT_SECURE_NO_WARNINGS
+#  define _CRT_SECURE_NO_WARNINGS
+#endif
+
 #include "fmt/format.h"
 #include "gtest-extra.h"
 

test/format-impl-test.cc

@@ -237,3 +237,19 @@ TEST(FormatTest, FormatErrorCode) {
 TEST(FormatTest, CountCodePoints) {
   EXPECT_EQ(4, fmt::internal::count_code_points(fmt::u8string_view("ёжик")));
 }
+
+// Tests fmt::internal::count_digits for integer type Int.
+template <typename Int> void test_count_digits() {
+  for (Int i = 0; i < 10; ++i) EXPECT_EQ(1u, fmt::internal::count_digits(i));
+  for (Int i = 1, n = 1, end = std::numeric_limits<Int>::max() / 10; n <= end;
+       ++i) {
+    n *= 10;
+    EXPECT_EQ(i, fmt::internal::count_digits(n - 1));
+    EXPECT_EQ(i + 1, fmt::internal::count_digits(n));
+  }
+}
+
+TEST(UtilTest, CountDigits) {
+  test_count_digits<uint32_t>();
+  test_count_digits<uint64_t>();
+}

test/format-test.cc

@@ -140,22 +140,6 @@ template <typename Char> struct WriteChecker {
   EXPECT_PRED_FORMAT1(WriteChecker<wchar_t>(), value)
 }  // namespace
 
-// Tests fmt::internal::count_digits for integer type Int.
-template <typename Int> void test_count_digits() {
-  for (Int i = 0; i < 10; ++i) EXPECT_EQ(1u, fmt::internal::count_digits(i));
-  for (Int i = 1, n = 1, end = std::numeric_limits<Int>::max() / 10; n <= end;
-       ++i) {
-    n *= 10;
-    EXPECT_EQ(i, fmt::internal::count_digits(n - 1));
-    EXPECT_EQ(i + 1, fmt::internal::count_digits(n));
-  }
-}
-
-TEST(UtilTest, CountDigits) {
-  test_count_digits<uint32_t>();
-  test_count_digits<uint64_t>();
-}
-
 struct uint32_pair {
   uint32_t u[2];
 };

test/posix-mock-test.cc

@@ -6,7 +6,7 @@
 // For the license information refer to format.h.
 
 // Disable bogus MSVC warnings.
-#ifdef _MSC_VER
+#ifndef _CRT_SECURE_NO_WARNINGS
 #  define _CRT_SECURE_NO_WARNINGS
 #endif