adding Serial.prinf(const char* format, ...)

platformio.ini

@@ -10,5 +10,7 @@
 
 [env:native]
 platform = native
-build_flags = -std=gnu++17
+build_flags = -std=gnu++17 -Wa,-mbig-obj
 test_build_src = yes
+;build_type = debug
+;debug_test = *

src/ArduinoFake.h

@@ -122,10 +122,11 @@ class ArduinoFakeContext
 
         void reset(void)
         {
+            ArduinoFakeInstances* newInstances = new ArduinoFakeInstances();
             if (this->Instances) {
                 delete this->Instances;
             }
-            this->Instances = new ArduinoFakeInstances();
+            this->Instances = newInstances;
 
             this->Mocks->Function.Reset();
             this->Mocks->Stream.Reset();

src/PrintFake.cpp

@@ -1,11 +1,40 @@
 #include "ArduinoFake.h"
 #include "PrintFake.h"
+#include <stdarg.h>
 
 size_t Print::write(const uint8_t *buffer, size_t size)
 {
     return ArduinoFakeInstance(Print, this)->write(buffer, size);
 }
 
+
+size_t Print::printf(const char *format, ...) {
+  va_list arg;
+  va_start(arg, format);
+
+  char loc_buf[64];
+  char *temp = loc_buf;
+  int len = vsnprintf(temp, sizeof(loc_buf), format, arg);
+  if (len < 0) {
+    va_end(arg);
+    return 0;
+  }
+  if (len >= (int)sizeof(loc_buf)) {  // comparison of same sign type for the compiler
+    temp = (char *)malloc(len + 1);
+    if (temp == NULL) {
+      va_end(arg);
+      return 0;
+    }
+    len = vsnprintf(temp, len + 1, format, arg);
+  }
+  va_end(arg);
+  len = write((uint8_t *)temp, len);
+  if (temp != loc_buf) {
+    free(temp);
+  }
+  return len;
+}
+
 size_t Print::print(const __FlashStringHelper *ifsh)
 {
     return ArduinoFakeInstance(Print, this)->print(ifsh);

src/PrintFake.h

@@ -8,6 +8,9 @@ struct PrintFake
     virtual size_t write(const uint8_t *buffer, size_t size) = 0;
     virtual size_t write(uint8_t) = 0;
 
+    virtual size_t printf(const char *format, ...) = 0;
+
+
     virtual size_t print(const __FlashStringHelper *) = 0;
     virtual size_t print(const String &) = 0;
     virtual size_t print(const char[]) = 0;

src/arduino/Print.h

@@ -57,6 +57,9 @@ class Print
     size_t write(const char *buffer, size_t size) {
       return write((const uint8_t *)buffer, size);
     }
+
+
+    size_t printf(const char *format, ...) __attribute__((format(printf, 2, 3)));
 
     size_t print(const __FlashStringHelper *);
     size_t print(const String &);

test/main.cpp

@@ -28,6 +28,10 @@ void setUp(void)
 {
     ArduinoFakeReset();
 }
+void tearDown(void)
+{
+
+}
 
 int main(int argc, char **argv)
 {

test/test_print.h

@@ -95,10 +95,27 @@ namespace PrintTest
         Verify(OverloadedMethod(ArduinoFake(Print), println, size_t(unsigned long, int)).Using(unsigned_long_var, DEC)).Once();
     }
 
+
+    void test_printf(void)
+    {
+        const char * format = "format %d %s";
+        int int_var = 123;
+        const char * char_array_var = "char_array_var";
+        const char * expected_output = "format 123 char_array_var";
+
+        When(OverloadedMethod(ArduinoFake(Print), write, size_t(const uint8_t *, size_t ))).AlwaysReturn(strlen(expected_output));
+        Print* print = ArduinoFakeMock(Print);
+
+        size_t result = print->printf(format, int_var, char_array_var);
+        TEST_ASSERT_EQUAL(strlen(expected_output), result);
+
+    }       
+
     void run_tests()
     {
-        RUN_TEST(PrintTest::test_print_variables);
         RUN_TEST(PrintTest::test_println_variables);
+        RUN_TEST(PrintTest::test_print_variables);
+        RUN_TEST(PrintTest::test_printf);
     }
 }