1.7 sample7--接口测试

值参数不限定类型，也可以是类的引用，这就可以实现对类接口的测试，一个基类可以有多个继承类，那么可以测试不同的子类功能，但是只需要写一个测试用例，然后使用参数列表实现对每个子类的测试。

使用值参数测试法去测试多个实现了相同接口（类）的共同属性（又叫做接口测试）

using ::testing::TestWithParam;
using ::testing::Values;
​
typedef PrimeTable* CreatePrimeTableFunc();
​
PrimeTable* CreateOnTheFlyPrimeTable() {return new OnTheFlyPrimeTable();
}
​
template 
PrimeTable* CreatePreCalculatedPrimeTable() {return new PreCalculatedPrimeTable(max_precalculated);
}
​
// Inside the test body, fixture constructor, SetUp(), and TearDown() you
// can refer to the test parameter by GetParam().  In this case, the test
// parameter is a factory function which we call in fixture's SetUp() to
// create and store an instance of PrimeTable.
class PrimeTableTestSmpl7 : public TestWithParam {public:~PrimeTableTestSmpl7() override { delete table_; }void SetUp() override { table_ = (*GetParam())(); }void TearDown() override {delete table_;table_ = nullptr;}
​protected:PrimeTable* table_;
};
​
TEST_P(PrimeTableTestSmpl7, ReturnsFalseForNonPrimes) {EXPECT_FALSE(table_->IsPrime(-5));EXPECT_FALSE(table_->IsPrime(0));EXPECT_FALSE(table_->IsPrime(1));EXPECT_FALSE(table_->IsPrime(4));EXPECT_FALSE(table_->IsPrime(6));EXPECT_FALSE(table_->IsPrime(100));
}
​
TEST_P(PrimeTableTestSmpl7, ReturnsTrueForPrimes) {EXPECT_TRUE(table_->IsPrime(2));EXPECT_TRUE(table_->IsPrime(3));EXPECT_TRUE(table_->IsPrime(5));EXPECT_TRUE(table_->IsPrime(7));EXPECT_TRUE(table_->IsPrime(11));EXPECT_TRUE(table_->IsPrime(131));
}TEST_P(PrimeTableTestSmpl7, CanGetNextPrime) {EXPECT_EQ(2, table_->GetNextPrime(1));EXPECT_EQ(3, table_->GetNextPrime(2));EXPECT_EQ(5, table_->GetNextPrime(3));EXPECT_EQ(7, table_->GetNextPrime(5));EXPECT_EQ(11, table_->GetNextPrime(7));EXPECT_EQ(131, table_->GetNextPrime(128));
}
​
// In order to run value-parameterized tests, you need to instantiate them,
// or bind them to a list of values which will be used as test parameters.
// You can instantiate them in a different translation module, or even
// instantiate them several times.
//
// Here, we instantiate our tests with a list of two PrimeTable object
// factory functions:
#define INSTANTIATE_TEST_SUITE_P INSTANTIATE_TEST_CASE_P
INSTANTIATE_TEST_SUITE_P(OnTheFlyAndPreCalculated, PrimeTableTestSmpl7,Values(&CreateOnTheFlyPrimeTable,&CreatePreCalculatedPrimeTable<1000>));

1.8sample8--值参数测试

有些时候，我们需要对代码实现的功能使用不同的参数进行测试，比如使用大量随机值来检验算法实现的正确性，或者比较同一个接口的不同实现之间的差别。gtest把“集中输入测试参数”的需求抽象出来提供支持，称为值参数化测试（Value Parameterized Test）。

代码实现

class HybridPrimeTable : public PrimeTable {public:HybridPrimeTable(bool force_on_the_fly, int max_precalculated): on_the_fly_impl_(new OnTheFlyPrimeTable),precalc_impl_(force_on_the_fly? nullptr: new PreCalculatedPrimeTable(max_precalculated)),max_precalculated_(max_precalculated) {}~HybridPrimeTable() override {delete on_the_fly_impl_;delete precalc_impl_;}
​bool IsPrime(int n) const override {if (precalc_impl_ != nullptr && n < max_precalculated_)return precalc_impl_->IsPrime(n);elsereturn on_the_fly_impl_->IsPrime(n);}
​int GetNextPrime(int p) const override {int next_prime = -1;if (precalc_impl_ != nullptr && p < max_precalculated_)next_prime = precalc_impl_->GetNextPrime(p);
​return next_prime != -1 ? next_prime : on_the_fly_impl_->GetNextPrime(p);}
​private:OnTheFlyPrimeTable* on_the_fly_impl_;PreCalculatedPrimeTable* precalc_impl_;int max_precalculated_;
};
​
using ::testing::TestWithParam;
using ::testing::Bool;
using ::testing::Values;
using ::testing::Combine;
​
// To test all code paths for HybridPrimeTable we must test it with numbers
// both within and outside PreCalculatedPrimeTable's capacity and also with
// PreCalculatedPrimeTable disabled. We do this by defining fixture which will
// accept different combinations of parameters for instantiating a
// HybridPrimeTable instance.
class PrimeTableTest : public TestWithParam< ::std::tuple > {protected:void SetUp() override {bool force_on_the_fly;int max_precalculated;std::tie(force_on_the_fly, max_precalculated) = GetParam();table_ = new HybridPrimeTable(force_on_the_fly, max_precalculated);}void TearDown() override {delete table_;table_ = nullptr;}HybridPrimeTable* table_;
};

PrimeTableTest类继承于TestWithParam，是测试固件类。接收参数tuple，如果bool为true时，使用OnTheFlyPrimeTable类的接口，当bool变量为false时，使用PreCalculatedPrimeTable接口测试。

测试编写：

TEST_P(PrimeTableTest, ReturnsFalseForNonPrimes) {EXPECT_FALSE(table_->IsPrime(-5));EXPECT_FALSE(table_->IsPrime(0));EXPECT_FALSE(table_->IsPrime(1));EXPECT_FALSE(table_->IsPrime(4));EXPECT_FALSE(table_->IsPrime(6));EXPECT_FALSE(table_->IsPrime(100));
}
​
TEST_P(PrimeTableTest, ReturnsTrueForPrimes) {EXPECT_TRUE(table_->IsPrime(2));EXPECT_TRUE(table_->IsPrime(3));EXPECT_TRUE(table_->IsPrime(5));EXPECT_TRUE(table_->IsPrime(7));EXPECT_TRUE(table_->IsPrime(11));EXPECT_TRUE(table_->IsPrime(131));
}
​
TEST_P(PrimeTableTest, CanGetNextPrime) {EXPECT_EQ(2, table_->GetNextPrime(0));EXPECT_EQ(3, table_->GetNextPrime(2));EXPECT_EQ(5, table_->GetNextPrime(3));EXPECT_EQ(7, table_->GetNextPrime(5));EXPECT_EQ(11, table_->GetNextPrime(7));EXPECT_EQ(131, table_->GetNextPrime(128));
}
​
​
#define INSTANTIATE_TEST_SUITE_P INSTANTIATE_TEST_CASE_P
INSTANTIATE_TEST_SUITE_P(MeaningfulTestParameters, PrimeTableTest,Combine(Bool(), Values(1, 10)));

共计3个测试case，测试名为MeaningfulTestParameters，输入的参数是一个comine类，生成正交参数集合：

Combine(Bool(), Values(1, 10)));
//  Combine() allows the user to combine two or more sequences to produce
//            values of a Cartesian product of those sequences' elements. 
/*|--Bool--|--------- Value---------||        |    1      |     10     ||  true  | (true,1)  | (true,10)  || false  | (false,1) | (false,10) |
*/

本例有3个测试，参数正交后是4组参数，每组参数运行一次测试，所以输出12个测试结果。运行截图如下。