Merge pull request #203 from arduino/fix-178

Fix of empty string printed in case of a 64-bit unsigned integer.

Author: aentinger

api/Print.cpp

@@ -287,6 +287,12 @@ size_t Print::printULLNumber(unsigned long long n64, uint8_t base)
   uint8_t i = 0;
   uint8_t innerLoops = 0;
 
+  // Special case workaround https://github.com/arduino/ArduinoCore-API/issues/178
+  if (n64 == 0) {
+    write('0');
+    return 1;
+  }
+
   // prevent crash if called with base == 1
   if (base < 2) base = 10;
 

test/src/Print/test_print.cpp

@@ -110,12 +110,24 @@ TEST_CASE ("Print::print(unsigned long long, int = DEC|HEX|OCT|BIN)", "[Print-pr
 {
   PrintMock mock;
 
-  unsigned long long const val = 17;
+  GIVEN("a value of zero ...")
+  {
+    unsigned long long const val = 0;
 
-  WHEN("DEC") { mock.print(val, DEC); REQUIRE(mock._str  == "17"); }
-  WHEN("HEX") { mock.print(val, HEX); REQUIRE(mock._str  == "11"); }
-  WHEN("OCT") { mock.print(val, OCT); REQUIRE(mock._str  == "21"); }
-  WHEN("BIN") { mock.print(val, BIN); REQUIRE(mock._str  == "10001"); }
+    WHEN("DEC") { mock.print(val, DEC); REQUIRE(mock._str  == "0"); }
+    WHEN("HEX") { mock.print(val, HEX); REQUIRE(mock._str  == "0"); }
+    WHEN("OCT") { mock.print(val, OCT); REQUIRE(mock._str  == "0"); }
+    WHEN("BIN") { mock.print(val, BIN); REQUIRE(mock._str  == "0"); }
+  }
+  GIVEN("a non-zero value ...")
+  {
+    unsigned long long const val = 17;
+
+    WHEN("DEC") { mock.print(val, DEC); REQUIRE(mock._str  == "17"); }
+    WHEN("HEX") { mock.print(val, HEX); REQUIRE(mock._str  == "11"); }
+    WHEN("OCT") { mock.print(val, OCT); REQUIRE(mock._str  == "21"); }
+    WHEN("BIN") { mock.print(val, BIN); REQUIRE(mock._str  == "10001"); }
+  }
 }
 
 TEST_CASE ("Print::print(double, int = 2)", "[Print-print-10]")