I am trying to create a tester using googletest. the problem is that the function that I am testing is returning void and printing a result instead. I want to get the last string printed into the console so I can test the output. the string may include \n
.
so I have the function itself:
void f_sequence(char sequenceStr[])
{
//logic...
if(condotion1)
printf("somthing1");
else if(condotion2)
printf("somthing2")
(...)
}
and then the tester:
TEST(TesterGroup, TesterName)
{
f_sequence("input");
EXPECT_EQ("somthing1", /*how do i get the output?*/);
}
Is it possible?
The functions I test are in c, while the Test function itself (the tester) is in c++. the output is printed using printf
. I cannot change the function itself. I am using CLion latest version.
Redirect the standard output to a buffer.
#include <stdio.h>
#include <unistd.h>
#define BUFFER_SIZE 1024
int stdoutSave;
char outputBuffer[BUFFER_SIZE];
void replaceStdout()
{
fflush(stdout); //clean everything first
stdoutSave = dup(STDOUT_FILENO); //save the stdout state
freopen("NUL", "a", stdout); //redirect stdout to null pointer
setvbuf(stdout, outputBuffer, _IOFBF, 1024); //set buffer to stdout
}
void restoreStdout()
{
freopen("NUL", "a", stdout); //redirect stdout to null again
dup2(stdoutSave, STDOUT_FILENO); //restore the previous state of stdout
setvbuf(stdout, NULL, _IONBF, BUFFER_SIZE); //disable buffer to print to screen instantly
}
void printHelloWorld()
{
printf("hello\n");
printf("world");
}
int main()
{
replaceStdout();
printHelloWorld();
restoreStdout();
// Use outputBuffer to test EXPECT_EQ("somthing1", outputBuffer);
printf("Fetched output: (%s)", outputBuffer);
return 0;
}
References: http://kaskavalci.com/redirecting-stdout-to-array-and-restoring-it-back-in-c/