Test negative precision.

format.cc

@@ -723,7 +723,6 @@ void fmt::BasicWriter<Char>::PrintfParser::Format(
           spec.precision_ = GetIntValue(arg);
         else if (!error)
           error = "precision is not integer";
-        // TODO: check for negative precision
       }
     }
 

test/printf-test.cc

@@ -266,11 +266,11 @@ TEST(PrintfTest, IgnorePrecisionForNonNumericArg) {
 
 TEST(PrintfTest, DynamicPrecision) {
   EXPECT_EQ("00042", str(fmt::sprintf("%.*d", 5, 42)));
+  EXPECT_EQ("42", str(fmt::sprintf("%.*d", -5, 42)));
   EXPECT_THROW_MSG(fmt::sprintf("%.*d", 5.0, 42), FormatError,
       "precision is not integer");
   EXPECT_THROW_MSG(fmt::sprintf("%.*d"), FormatError,
       "argument index is out of range in format");
-  // TODO: more tests
 }
 
 // TODO: test length and type specifier