单元测试使用gtest 1.6：如何检查什么是打印输出？ [英] unit test using gtest 1.6 : how to check what is printed out?

问题描述

如何检查打印到命令行的void函数？

How do i check a void function that print out sth to the command line?

例如：

void printFoo() {
                 cout << "Successful" < endl;
             }

然后在test.cpp我把这个测试用例：

and then in the test.cpp i put this test case:

TEST(test_printFoo, printFoo) {

    //what do i write here??

}

请解释清楚，因为我是新的单元测试gtest。谢谢

please explain clearly as i'm new to unit testing and gtest. Thank you

推荐答案

您必须更改函数才能使其可测试。最简单的方法是在你的单元测试中传递一个ostream（cout继承）到该函数，并使用一个字符串流（也继承ostream）。

You will have to change your function to make it testable. The easiest way to do this is to pass in an ostream ( which cout inherits ) to the function, and use a string stream ( also inherits ostream ) in your unit tests.

void printFoo( std::ostream &os ) 
{
  os << "Successful" << endl;
}

TEST(test_printFoo, printFoo) 
{
  std::ostringstream output;

  printFoo( output );

  // Not that familiar with gtest, but I think this is how you test they are 
  // equal. Not sure if it will work with stringstream.
  EXPECT_EQ( output, "Successful" );

  // For reference, this is the equivalent assert in mstest
  // Assert::IsTrue( output == "Successful" );
}

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