fe483c056d
This is done by no longer requiring all assertions to be seen
by the JUnit reporter. Since the JUnit reporter never outputs
all assertions, even with `-s`, the only difference from storing
passing assertions in the `CumulativeReporterBase` was some
bookkeeping in deciding which sections are relevant to the output.
Given `TEST_CASE` that just runs many passing assertions, e.g.
```
TEST_CASE( "PERFORMANCE_TEST_CASE", "[.]" ) {
for (size_t i = 0; i < 1000'000'000; ++i) {
REQUIRE( i == i );
}
}
```
the new JUnit reporter will finish in 5:47, using up ~7.7 MB of RAM.
The old JUnit reporter would finish in 0:30, due to bad_alloc
after using up 14.5 GB of RAM (the system has 16 GB total).
If the total number of assertions is lowered to 10M, the old
implementation uses up ~7.1 GB of RAM and finishes in 12 minutes.
The new implementation still needs only ~7.7 MB of RAM, and finishes
in 4 minutes.
There is a slight downside in that the output is slightly different;
the new implementation will include the `TEST_CASE` level section
in output, even if it does not have its own assertion. In other words,
given a `TEST_CASE` like this
```
TEST_CASE( "JsonWriter", "[JSON][JsonWriter]" ) {
std::stringstream stream;
SECTION( "Newly constructed JsonWriter does nothing" ) {
Catch::JsonValueWriter writer{ stream };
REQUIRE( stream.str() == "" );
}
SECTION( "Calling writeObject will create an empty pair of braces" ) {
{ auto writer = Catch::JsonValueWriter{ stream }.writeObject(); }
REQUIRE( stream.str() == "{\n}" );
}
}
```
the new implementation will output 3 `testcase` tags, 2 for the explicit
`SECTION`s with tests, and 1 for the top level section.
However, this can be worked-around if required, and the performance
improvement is such that it is worth changing the current output,
even if it needs to be fixed in the future.
Closes #2897
What is Catch2?
Catch2 is mainly a unit testing framework for C++, but it also provides basic micro-benchmarking features, and simple BDD macros.
Catch2's main advantage is that using it is both simple and natural. Test names do not have to be valid identifiers, assertions look like normal C++ boolean expressions, and sections provide a nice and local way to share set-up and tear-down code in tests.
Example unit test
#include <catch2/catch_test_macros.hpp>
#include <cstdint>
uint32_t factorial( uint32_t number ) {
return number <= 1 ? number : factorial(number-1) * number;
}
TEST_CASE( "Factorials are computed", "[factorial]" ) {
REQUIRE( factorial( 1) == 1 );
REQUIRE( factorial( 2) == 2 );
REQUIRE( factorial( 3) == 6 );
REQUIRE( factorial(10) == 3'628'800 );
}
Example microbenchmark
#include <catch2/catch_test_macros.hpp>
#include <catch2/benchmark/catch_benchmark.hpp>
#include <cstdint>
uint64_t fibonacci(uint64_t number) {
return number < 2 ? number : fibonacci(number - 1) + fibonacci(number - 2);
}
TEST_CASE("Benchmark Fibonacci", "[!benchmark]") {
REQUIRE(fibonacci(5) == 5);
REQUIRE(fibonacci(20) == 6'765);
BENCHMARK("fibonacci 20") {
return fibonacci(20);
};
REQUIRE(fibonacci(25) == 75'025);
BENCHMARK("fibonacci 25") {
return fibonacci(25);
};
}
Note that benchmarks are not run by default, so you need to run it explicitly
with the [!benchmark] tag.
Catch2 v3 has been released!
You are on the devel branch, where the v3 version is being developed.
v3 brings a bunch of significant changes, the big one being that Catch2
is no longer a single-header library. Catch2 now behaves as a normal
library, with multiple headers and separately compiled implementation.
The documentation is slowly being updated to take these changes into account, but this work is currently still ongoing.
For migrating from the v2 releases to v3, you should look at our documentation. It provides a simple guidelines on getting started, and collects most common migration problems.
For the previous major version of Catch2 look into the v2.x branch
here on GitHub.
How to use it
This documentation comprises these three parts:
- Why do we need yet another C++ Test Framework?
- Tutorial - getting started
- Reference section - all the details
More
- Issues and bugs can be raised on the Issue tracker on GitHub
- For discussion or questions please use our Discord
- See who else is using Catch2 in Open Source Software or commercially.