mirror of
https://github.com/catchorg/Catch2.git
synced 2024-11-23 05:46:11 +01:00
51 lines
1.6 KiB
Markdown
51 lines
1.6 KiB
Markdown
<a id="top"></a>
|
|
# Data Generators
|
|
|
|
_Generators are currently considered an experimental feature and their
|
|
API can change between versions freely._
|
|
|
|
Data generators (also known as _data driven/parametrized test cases_)
|
|
let you reuse the same set of assertions across different input values.
|
|
In Catch2, this means that they respect the ordering and nesting
|
|
of the `TEST_CASE` and `SECTION` macros.
|
|
|
|
How does combining generators and test cases work might be better
|
|
explained by an example:
|
|
|
|
```cpp
|
|
TEST_CASE("Generators") {
|
|
auto i = GENERATE( range(1, 11) );
|
|
|
|
SECTION( "Some section" ) {
|
|
auto j = GENERATE( range( 11, 21 ) );
|
|
REQUIRE(i < j);
|
|
}
|
|
}
|
|
```
|
|
|
|
the assertion will be checked 100 times, because there are 10 possible
|
|
values for `i` (1, 2, ..., 10) and for each of them, there are 10 possible
|
|
values for `j` (11, 12, ..., 20).
|
|
|
|
You can also combine multiple generators by concatenation:
|
|
```cpp
|
|
static int square(int x) { return x * x; }
|
|
TEST_CASE("Generators 2") {
|
|
auto i = GENERATE(0, 1, -1, range(-20, -10), range(10, 20));
|
|
CAPTURE(i);
|
|
REQUIRE(square(i) >= 0);
|
|
}
|
|
```
|
|
|
|
This will call `square` with arguments `0`, `1`, `-1`, `-20`, ..., `-11`,
|
|
`10`, ..., `19`.
|
|
|
|
----------
|
|
|
|
Because of the experimental nature of the current Generator implementation,
|
|
we won't list all of the first-party generators in Catch2. Instead you
|
|
should look at our current usage tests in
|
|
[projects/SelfTest/UsageTests/Generators.tests.cpp](/projects/SelfTest/UsageTests/Generators.tests.cpp).
|
|
For implementing your own generators, you can look at their implementation in
|
|
[include/internal/catch_generators.hpp](/include/internal/catch_generators.hpp).
|