文章目录
- 1.简介
- 2.用法
1.简介
示例#3使用测试fixture(固定)
2.用法
CMakeLists.txt
cmake_minimum_required(VERSION 3.0.0)
project(hello_gtest VERSION 0.1.0)
add_executable(${PROJECT_NAME} main.cc sample.cc sample_unitest.cc)
target_link_libraries(${PROJECT_NAME} gtest pthread)
main.cc
#include <gtest/gtest.h>
int main(int argc, char *argv[])
{
testing::InitGoogleTest(&argc, argv);
return RUN_ALL_TESTS();
}
sample.h
// A sample program demonstrating using Google C++ testing framework.
#ifndef GOOGLETEST_SAMPLES_SAMPLE3_INL_H_
#define GOOGLETEST_SAMPLES_SAMPLE3_INL_H_
#include <stddef.h>
// Queue is a simple queue implemented as a singled-linked list.
//
// The element type must support copy constructor.
template <typename E> // E is the element type
class Queue;
// QueueNode is a node in a Queue, which consists of an element of
// type E and a pointer to the next node.
template <typename E> // E is the element type
class QueueNode {
friend class Queue<E>;
public:
// Gets the element in this node.
const E& element() const { return element_; }
// Gets the next node in the queue.
QueueNode* next() { return next_; }
const QueueNode* next() const { return next_; }
private:
// Creates a node with a given element value. The next pointer is
// set to NULL.
explicit QueueNode(const E& an_element)
: element_(an_element), next_(nullptr) {}
// We disable the default assignment operator and copy c'tor.
const QueueNode& operator = (const QueueNode&);
QueueNode(const QueueNode&);
E element_;
QueueNode* next_;
};
template <typename E> // E is the element type.
class Queue {
public:
// Creates an empty queue.
Queue() : head_(nullptr), last_(nullptr), size_(0) {}
// D'tor. Clears the queue.
~Queue() { Clear(); }
// Clears the queue.
void Clear() {
if (size_ > 0) {
// 1. Deletes every node.
QueueNode<E>* node = head_;
QueueNode<E>* next = node->next();
for (; ;) {
delete node;
node = next;
if (node == nullptr) break;
next = node->next();
}
// 2. Resets the member variables.
head_ = last_ = nullptr;
size_ = 0;
}
}
// Gets the number of elements.
size_t Size() const { return size_; }
// Gets the first element of the queue, or NULL if the queue is empty.
QueueNode<E>* Head() { return head_; }
const QueueNode<E>* Head() const { return head_; }
// Gets the last element of the queue, or NULL if the queue is empty.
QueueNode<E>* Last() { return last_; }
const QueueNode<E>* Last() const { return last_; }
// Adds an element to the end of the queue. A copy of the element is
// created using the copy constructor, and then stored in the queue.
// Changes made to the element in the queue doesn't affect the source
// object, and vice versa.
void Enqueue(const E& element) {
QueueNode<E>* new_node = new QueueNode<E>(element);
if (size_ == 0) {
head_ = last_ = new_node;
size_ = 1;
} else {
last_->next_ = new_node;
last_ = new_node;
size_++;
}
}
// Removes the head of the queue and returns it. Returns NULL if
// the queue is empty.
E* Dequeue() {
if (size_ == 0) {
return nullptr;
}
const QueueNode<E>* const old_head = head_;
head_ = head_->next_;
size_--;
if (size_ == 0) {
last_ = nullptr;
}
E* element = new E(old_head->element());
delete old_head;
return element;
}
// Applies a function/functor on each element of the queue, and
// returns the result in a new queue. The original queue is not
// affected.
template <typename F>
Queue* Map(F function) const {
Queue* new_queue = new Queue();
for (const QueueNode<E>* node = head_; node != nullptr;
node = node->next_) {
new_queue->Enqueue(function(node->element()));
}
return new_queue;
}
private:
QueueNode<E>* head_; // The first node of the queue.
QueueNode<E>* last_; // The last node of the queue.
size_t size_; // The number of elements in the queue.
// We disallow copying a queue.
Queue(const Queue&);
const Queue& operator = (const Queue&);
};
#endif // GOOGLETEST_SAMPLES_SAMPLE3_INL_H_
sample_unitest.cc
首先声明了一个 test fixture 类，在这个类中实现了一些测试时用到的辅助函数，以及使用SetUp预置了一些测试数据。（除了有特殊需求，则不需要实现TearDown，因为析构函数已经帮我们释放了资源）
// A sample program demonstrating using Google C++ testing framework.
// In this example, we use a more advanced feature of Google Test called
// test fixture.
//
// A test fixture is a place to hold objects and functions shared by
// all tests in a test case. Using a test fixture avoids duplicating
// the test code necessary to initialize and cleanup those common
// objects for each test. It is also useful for defining sub-routines
// that your tests need to invoke a lot.
//
// <TechnicalDetails>
//
// The tests share the test fixture in the sense of code sharing, not
// data sharing. Each test is given its own fresh copy of the
// fixture. You cannot expect the data modified by one test to be
// passed on to another test, which is a bad idea.
//
// The reason for this design is that tests should be independent and
// repeatable. In particular, a test should not fail as the result of
// another test's failure. If one test depends on info produced by
// another test, then the two tests should really be one big test.
//
// The macros for indicating the success/failure of a test
// (EXPECT_TRUE, FAIL, etc) need to know what the current test is
// (when Google Test prints the test result, it tells you which test
// each failure belongs to). Technically, these macros invoke a
// member function of the Test class. Therefore, you cannot use them
// in a global function. That's why you should put test sub-routines
// in a test fixture.
//
// </TechnicalDetails>
#include "sample3-inl.h"
#include "gtest/gtest.h"
namespace {
// To use a test fixture, derive a class from testing::Test.
class QueueTestSmpl3 : public testing::Test {
protected: // You should make the members protected s.t. they can be
// accessed from sub-classes.
// virtual void SetUp() will be called before each test is run. You
// should define it if you need to initialize the variables.
// Otherwise, this can be skipped.
void SetUp() override {
q1_.Enqueue(1);
q2_.Enqueue(2);
q2_.Enqueue(3);
}
// virtual void TearDown() will be called after each test is run.
// You should define it if there is cleanup work to do. Otherwise,
// you don't have to provide it.
//
// virtual void TearDown() {
// }
// A helper function that some test uses.
static int Double(int n) {
return 2*n;
}
// A helper function for testing Queue::Map().
void MapTester(const Queue<int> * q) {
// Creates a new queue, where each element is twice as big as the
// corresponding one in q.
const Queue<int> * const new_q = q->Map(Double);
// Verifies that the new queue has the same size as q.
ASSERT_EQ(q->Size(), new_q->Size());
// Verifies the relationship between the elements of the two queues.
for (const QueueNode<int>*n1 = q->Head(), *n2 = new_q->Head();
n1 != nullptr; n1 = n1->next(), n2 = n2->next()) {
EXPECT_EQ(2 * n1->element(), n2->element());
}
delete new_q;
}
// Declares the variables your tests want to use.
Queue<int> q0_;
Queue<int> q1_;
Queue<int> q2_;
};
// When you have a test fixture, you define a test using TEST_F
// instead of TEST.
// Tests the default c'tor.
TEST_F(QueueTestSmpl3, DefaultConstructor) {
// You can access data in the test fixture here.
EXPECT_EQ(0u, q0_.Size());
}
// Tests Dequeue().
TEST_F(QueueTestSmpl3, Dequeue) {
int * n = q0_.Dequeue();
EXPECT_TRUE(n == nullptr);
n = q1_.Dequeue();
ASSERT_TRUE(n != nullptr);
EXPECT_EQ(1, *n);
EXPECT_EQ(0u, q1_.Size());
delete n;
n = q2_.Dequeue();
ASSERT_TRUE(n != nullptr);
EXPECT_EQ(2, *n);
EXPECT_EQ(1u, q2_.Size());
delete n;
}
// Tests the Queue::Map() function.
TEST_F(QueueTestSmpl3, Map) {
MapTester(&q0_);
MapTester(&q1_);
MapTester(&q2_);
}
} // namespace
这里以 DefaultConstructor 为例，来分析一下它的执行流程：
QueueTestSmpl3 调用构造函数，构造对象。
QueueTestSmpl3 对象调用 SetUp 函数初始化测试配置。
DefaultConstructor 开始执行并结束测试。
QueueTestSmpl3 对象调用隐式生成的 TearDown 进行清理。
QueueTestSmpl3 调用析构函数，析构对象。
- ref：gtest sample
