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Methods to measure function unit test coverage in C include: using compiler flags, such as GCC's -fprofile-arcs and -ftest-coverage flags; using test frameworks, such as Google Test's --gtest_output=xml flag; Use external tools such as CovWrap.
#How to measure the coverage of C function unit tests?
Code coverage is an important indicator of unit test quality. It indicates how much function code was covered by the test suite when executed. In C, there are several ways to measure coverage.
Using Compiler Flags
Many compilers provide flags for measuring coverage. For example, using the GCC compiler:
g++ -fprofile-arcs -ftest-coverage your_code.cpp
After executing the program, it will generate a file named gcov.out
in the current directory, which contains coverage information.
Using testing frameworks
Testing frameworks such as Google Test (gtest) provide built-in coverage measurement tools. In gtest, run the test using the --gtest_output=xml
flag:
gtest your_test_case --gtest_output=xml
This will generate an XML file containing the coverage data.
Using external tools
CovWrap is an external tool that can generate gcov output. It is available for Windows and Linux systems.
Practical case
Consider a simple C function:
int sum(int a, int b) { return a + b; }
Create a unit test to test this function:
#include "gtest/gtest.h" TEST(SumTest, PositiveValues) { EXPECT_EQ(sum(1, 2), 3); }
Run the test using gtest and generate a coverage report:
gtest SumTest --gtest_output=xml
The generated XML report will show that the test covers the following lines of code for the sum
function:
return a + b;
This indicates that the test Use cases can override the function's logic.
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