Question

我有一个类型为

的模板类

<size_t N>
class Line {
   ...
};

我怎么能为这个类的几个实例创建一个测试？例如行＆lt; 1＆gt;，行＆lt; 2＆gt;，...

我查了一下文档，有：

值 - 参数化测试，适用于运行时值
Type-Parametrized测试，允许您在编译时更改typename。

但是，我没有找到任何在编译时更改值的内容。

Answer 1

Googletest没有现成的解决方案来生成测试一组非类型模板参数的模板，如您所愿。

假设C ++ 11或更高版本，您可以利用std::integral_constant<T,N> 创建一个唯一代表std::size_t范围的类的类您希望测试涵盖N的参数Line<N>，并使用std::integral_constant<std::size_t,N> 作为N的代理来构建TYPED_TEST_CASE和关联的TYPED_TEST。像这样：

玩具Line课程用于说明：

<强> Line.h

#ifndef LINE_H
#define LINE_H
#include <cstddef>

template <std::size_t N>
class Line {
public:
    static constexpr std::size_t capacity() {
        return N;
    }
    explicit Line(std::size_t n)
    : _length{n < N ? n : N}{};

    std::size_t length() const {
        return _length;
    }

private:
    std::size_t _length = 0;

};

#endif

Googletest测试跑步者：

<强> line_test.cpp

#include <gtest/gtest.h>
#include <type_traits>
#include "line.h"

template <typename T>
class line_tester : public ::testing::Test{};

using test_types = ::testing::Types<
    std::integral_constant<std::size_t,2>,
    std::integral_constant<std::size_t,3>, 
    std::integral_constant<std::size_t,5>>;

TYPED_TEST_CASE(line_tester, test_types);

TYPED_TEST(line_tester, get_capacity) {
    static constexpr std::size_t n = TypeParam::value;
    ASSERT_EQ(n,Line<n>::capacity());
}

TYPED_TEST(line_tester, set_length_preserved) {
    Line<TypeParam::value> line{1};
    ASSERT_EQ(line.length(),1);
}

TYPED_TEST(line_tester, set_length_trunctated) {
    static constexpr std::size_t n = TypeParam::value;
    Line<n> line{999};
    ASSERT_EQ(line.length(),Line<n>::capacity());
}

int main(int argc, char **argv) {
  ::testing::InitGoogleTest(&argc, argv);
  return RUN_ALL_TESTS();
}

运行方式如下：

$ ./line_tester 
[==========] Running 9 tests from 3 test cases.
[----------] Global test environment set-up.
[----------] 3 tests from line_tester/0, where TypeParam = std::integral_constant<unsigned long, 2ul>
[ RUN      ] line_tester/0.get_capacity
[       OK ] line_tester/0.get_capacity (0 ms)
[ RUN      ] line_tester/0.set_length_preserved
[       OK ] line_tester/0.set_length_preserved (0 ms)
[ RUN      ] line_tester/0.set_length_trunctated
[       OK ] line_tester/0.set_length_trunctated (0 ms)
[----------] 3 tests from line_tester/0 (1 ms total)

[----------] 3 tests from line_tester/1, where TypeParam = std::integral_constant<unsigned long, 3ul>
[ RUN      ] line_tester/1.get_capacity
[       OK ] line_tester/1.get_capacity (0 ms)
[ RUN      ] line_tester/1.set_length_preserved
[       OK ] line_tester/1.set_length_preserved (0 ms)
[ RUN      ] line_tester/1.set_length_trunctated
[       OK ] line_tester/1.set_length_trunctated (0 ms)
[----------] 3 tests from line_tester/1 (0 ms total)

[----------] 3 tests from line_tester/2, where TypeParam = std::integral_constant<unsigned long, 5ul>
[ RUN      ] line_tester/2.get_capacity
[       OK ] line_tester/2.get_capacity (0 ms)
[ RUN      ] line_tester/2.set_length_preserved
[       OK ] line_tester/2.set_length_preserved (0 ms)
[ RUN      ] line_tester/2.set_length_trunctated
[       OK ] line_tester/2.set_length_trunctated (0 ms)
[----------] 3 tests from line_tester/2 (0 ms total)

[----------] Global test environment tear-down
[==========] 9 tests from 3 test cases ran. (1 ms total)
[  PASSED  ] 9 tests.

为模板类创建gtest值参数化测试

1 个答案: