单元测试学习笔记之三

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单元测试学习笔记之三

发布于2011-08-09

第三章单元测试的工具——测试框架

3.1 常用的单元测试框架

工欲善其事, 必先利其器. 程序员在写单元测试代码时, 如果能借助一些单元测试框架, 那么使单元测试代码的书写、维护、分类、存档、运行和结果检查变得更为容易, 从而成倍地提高工作效率. 在本章中, 我们就将学习两种单元测试的框架.

第一种, 就是鼎鼎大名的xUnit测试框架家族. xUnit测试框架有助于我们更加结构化地书写测试代码, 更方便地运行单元测试并检查运行结果.

第二种框架称为隔离框架(isolation framework). 这种框架旨在帮助程序员自动地生成FakeCollaboratorClass代码. 但是隔离框架一般都要求ClassUnderTest依赖于CollaboratorService抽象接口, 而不是具体类CollaboratorClass, 所以在使用"Virtual and Override"手法时, 隔离框架就帮不忙了, 必须由程序员手写FakeCollaboratorClass的代码.

在接下来的几个小节中, 我们将针对C++, C#和Java语言, 分别介绍适用于它们的单元测试框架.

3.2 用于C++的单元测试框架

对于C++, 我们推荐使用Google C++ Unit Testing Framework(简称gTest, 目前为1.5版)加HippoMocks(目前为3.1版)的组合. 如下的表格演示了如何使用这两个框架.

gTest的基本用法
声明Test Fixture	#ifndef CLASS_UNDER_TEST_TEST_H #define CLASS_UNDER_TEST_TEST_H // In [ClassUnderTest]Test.h file. #include <gtest/gtest.h> // Test Fixture declaration. class [ClassUnderTest]Test : public testing::Test { protected: // Optional SetUp() and TearDown(). virtual void SetUp(); virtual void TearDown(); }; #endif
定义Test Method	// In [ClassUnderTest]Test.cpp file. #include <gtest/gtest.h> #include <hippomocks.h> #include "[ClassUnderTest]Test.h" // Optional SetUp() and TearDown(). void [ClassUnderTest]Test::SetUp() { ... } void [ClassUnderTest]Test::TearDown() { ... } // Test Method definition. TEST_F([ClassUnderTest]Test, [Feature]_[Scenario]_[ExpectedBehavior]) { ... } // Temporarily ignore a test case. TEST_F([ClassUnderTest]Test, DISABLE_[Feature]_[Scenario]_[ExpectedBehavior]) { ... }
Test Runner	// Currently, gTest only supports CUI. The main() should be like this. #include <gtest/gtest.h> #include "[ClassUnderTest]Test.h" int main(int argc, char** argv) { testing::InitGoogleTest(&argc, argv); return RUN_ALL_TESTS(); }

gTest支持的命令行参数
--gtest-filter=[filter]	对执行的测试案例进行过滤，支持 ? 单个字符 * 任意字符 - 排除，如，-a 表示除了a : 取或，如，a:b 表示a或b 比如下面的例子: ./foo_test 没有指定过滤条件, 运行所有案例 ./foo_test --gtest_filter=* 使用通配符, 表示运行所有案例 ./foo_test --gtest_filter=FooTest. 运行所有[ClassUnderTest]Test为FooTest的案例 ./foo_test --gtest_filter=FooTest.*-FooTest.Bar 运行所有[ClassUnderTest]Test为FooTest的案例, 但是除了FooTest.Bar这个案例
--gtest_repeat=[COUNT]	设置案例重复运行次数. 比如: --gtest_repeat=1000 重复执行1000次, 即使中途出现错误. --gtest_repeat=1000 --gtest_break_on_failure 重复执行1000次, 并且在第一个错误发生时立即停止. 这个功能对调试非常有用.
--gtest_print_time	打印每个测试方法运行的所用时间.
--gtest_catch_exceptions	捕捉异常. 这样当测试方法中抛出了异常时, 不会阻碍了后续测试方法的运行. 注意: 这个参数只在Windows下有效.
--gtest_output=xml[:DIRECTORY_PATH/\|:FILE_PATH]	产生XML格式的报告。

gTest支持的断言
断言真伪	ASSERT_TRUE(condition) [<< message]; ASSERT_FALSE(condition) [<< message];
断言比较关系	ASSERT_EQ(expected, actual) [<< message]; ASSERT_NE(expected, actual) [<< message]; ASSERT_LT(expected, actual) [<< message]; ASSERT_LE(expected, actual) [<< message]; ASSERT_GT(expected, actual) [<< message]; ASSERT_GE(expected, actual) [<< message]; ASSERT_FLOAT_EQ(expected, actual) [<< message]; ASSERT_DOUBLE_EQ(expected, actual) [<< message]; ASSERT_NEAR(expected, actual, tolerance) [<< message];
断言C字符串关系	ASSERT_STREQ(expected_cstr, actual_cstr) [<< message]; ASSERT_STRNE(expected_cstr, actual_cstr) [<< message]; ASSERT_STRCASEEQ(expected_cstr, actual_cstr) [<< message]; ASSERT_STRCASENE(expected_cstr, actual_cstr) [<< message];
断言异常	ASSERT_THROW({ statements }, exception_ctor); ASSERT_NO_THROW({ statements }); ASSERT_ANY_THROW({ statements });

HippoMocks用于动态stub生成
准备工作	// In [ClassUnderTest]Test.cpp file. #include <gtest/gtest.h> #include <hippomocks.h> #include "[ClassUnderTest]Test.h" // Test Method definition. TEST_F([ClassUnderTest]Test, [Feature]_[Scenario]_[ExpectedBehavior]) { MockRepository mockEngine; CollaboratorService* stub = mockEngine.InterfaceMock<CollaboratorService>(); ... }
指定返回值	// We don't care about the passed-in arguments for CollaboratorService::methodName(). mockEngine.OnCall(stub, CollaboratorService::methodName).Return(stubResult); // We care about the passed-in arguments for CollaboratorService::methodName(). mockEngine.OnCall(stub, CollaboratorService::methodName).With(arg1, arg2, ...).Return(stubResult); // If CollaboratorService::methodName() is overloaded, use the following invocation forms. mockEngine.OnCallOverload(stub, (return_type(CollaboratorService::)(arg1_type, arg2_type, ...))&CollaboratorService::methodName).Return(stubResult); mockEngine.OnCallOverload(stub, (return_type(CollaboratorService::)(arg1_type, arg2_type, ...))&CollaboratorService::methodName).With(arg1, arg2, ...).Return(stubResult);
指定抛出异常	// We don't care about the passed-in arguments for CollaboratorService::methodName(). mockEngine.OnCall(stub, CollaboratorService::methodName).Throw(exception_ctor()); // We care about the passed-in arguments for CollaboratorService::methodName(). mockEngine.OnCall(stub, CollaboratorService::methodName).With(arg1, arg2, ...).Throw(exception_ctor()); // If CollaboratorService::methodName() is overloaded, use the following invocation forms. mockEngine.OnCallOverload(stub, (return_type(CollaboratorService::)(arg1_type, arg2_type, ...))&CollaboratorService::methodName).Throw(exception_ctor()); mockEngine.OnCallOverload(stub, (return_type(CollaboratorService::)(arg1_type, arg2_type, ...))&CollaboratorService::methodName).With(arg1, arg2, ...).Throw(exception_ctor());

HippoMocks用于动态mock生成
准备工作	// In [ClassUnderTest]Test.cpp file. #include <gtest/gtest.h> #include <hippomocks.h> #include "[ClassUnderTest]Test.h" // Test Method definition. TEST_F([ClassUnderTest]Test, [Feature]_[Scenario]_[ExpectedBehavior]) { MockRepository mockEngine; CollaboratorService* mock = mockEngine.InterfaceMock<CollaboratorService>(); ... }
设置期望: 一定不被调用	mockEngine.NeverCall(mock, CollaboratorService::methodName); mockEngine.NeverCallOverload(mock, (return_type(CollaboratorService::*)(arg1_type, arg2_type, ...))&CollaboratorService::methodName);
设置期望: 不一定被调用	mockEngine.OnCall(mock, CollaboratorService::methodName); mockEngine.OnCallOverload(mock, (return_type(CollaboratorService::*)(arg1_type, arg2_type, ...))&CollaboratorService::methodName);
设置期望: 不一定被调用, 但如果一旦被调, 那么关心输入参数	mockEngine.OnCall(mock, CollaboratorService::methodName).With(arg1, arg2, ...); mockEngine.OnCallOverload(mock, (return_type(CollaboratorService::*)(arg1_type, arg2_type, ...))&CollaboratorService::methodName).With(arg1, arg2, ...);
设置期望: 一定被调用, 但不关心输入参数	mockEngine.ExpectCall(mock, CollaboratorService::methodName); mockEngine.ExpectCallOverload(mock, (return_type(CollaboratorService::*)(arg1_type, arg2_type, ...))&CollaboratorService::methodName);
设置期望: 一定被调用, 并关心输入参数	mockEngine.ExpectCall(mock, CollaboratorService::methodName).With(arg1, arg2, ...); mockEngine.ExpectCallOverload(mock, (return_type(CollaboratorService::*)(arg1_type, arg2_type, ...))&CollaboratorService::methodName).With(arg1, arg2, ...);
设置期望: 一定被调用, 但不关心被调用的次序	mockEngine.autoExpect = false; mockEngine.ExpectCall(mock, CollaboratorService::methodName1); mockEngine.ExpectCall(mock, CollaboratorService::methodName2);
设置期望: 一定被调用, 并关心被调用的次序	mockEngine.ExpectCall(mock, CollaboratorService::methodName1); mockEngine.ExpectCall(mock, CollaboratorService::methodName2);
显式验证	mockEngine.VerifyAll();

3.3 用于C#的单元测试框架

对于C#, 我们推荐使用NUnit(目前为2.5版)加RhinoMocks(目前为3.6版)的组合. 如下的表格演示了如何使用这两个框架.

NUnit的基本用法

Test Fixture和Test Method

using NUnit.Framework;
using Rhino.Mocks;
[TestFixture]
public class [ClassUnderTest]Test
{
    [SetUp]
    public void SetUp()
    {
        ...
    }
    [TearDown]
    public void TearDown()
    {
        ...
    }
    [Test]
    public void [Feature]_[Scenario]_[ExpectedResult]()
    {
        ...
    }

// Temporarily ignore a test case.

[Test]

[Ignore]
    public void [Feature]_[Scenario]_[ExpectedResult]()
    {
        ...
    }

}

Test Runner

NUnit提供了GUI界面的Test Runner, 只需把编译生成的程序集(assembly)加载到该Test Runner中即可.

NUnit支持的断言
断言真伪	Assert.That(condition, Is.True); Assert.That(condition, Is.False);
断言比较关系	Assert.That(actual, Is[.Not].EqualTo(expected)); Assert.That(actual. Is.LessThan(expected)); Assert.That(actual. Is.GreaterThan(expected)); Assert.That(actual. Is.AtMost(expected)); Assert.That(actual. Is.AtLeast(expected)); Assert.That(actual. Is.LessThan(expected)); Assert.That(actual. Is.EqualTo(expected).Within(tolerance));
断言对象关系	Assert.That(obj, Is[.Not].Null); Assert.That(obj, Is[.Not].InstanceOfType(type)); Assert.That(actualObj, Is[.Not].SameAs(expectedObj));
断言容器关系	Assert.That(container, Is[.Not].Empty); Assert.That(container, Has.Length(length));
断言字符串关系	Assert.That(actual, Is[.Not].EqualTo(expected)[.IgnoreCase]); Assert.That(phrase, Is[.Not].StringContaining(substring)[.IgnoreCase]); Assert.That(phrase, StartsWith(substring)[.IgnoreCase]); Assert.That(phrase, EndsWith(substring)[.IgnoreCase]);
断言异常	Assert.That(() => { statements }, Throws.Exception.TypeOf<exception_ctor>()); Assert.That(() => { statements }, Throws.Exception); Assert.That(() => { statements }, Throws.Nothing;

RhinoMocks用于动态stub生成
准备工作	using NUnit.Framework; using Rhino.Mocks; [TestFixture] public class [ClassUnderTest]Test { [Test] public void [Feature]_[Scenario]_[ExpectedResult]() { MockRepository mockEngine = new MockRepository(); CollaboratorService stub = mockEngine.Stub<CollaboratorService>(); ... mockEngine.ReplayAll(); ... } }
指定返回值	// We don't care about the passed-in arguments for CollaboratorService::methodName(). Expect.Call(stub.methodName(dummy1, dummy2, dummy3, ...)).Return(stubResult); // We care about the passed-in arguments for CollaboratorService::methodName(). Expect.Call(stub.methodName(dummy1, dummy2, dummy3, ...)). Constraints(Rhino.Mocks.Constraints.Is.Equal(arg1), Rhino.Mocks.Constraints.Is.Null(), Rhino.Mocks.Constraints.Is.Same(arg3), ...). Return(stubResult);
指定抛出异常	// We don't care about the passed-in arguments for CollaboratorService::methodName(). Expect.Call(stub.methodName(dummy1, dummy2, dummy3, ...)). Constraints(Rhino.Mocks.Constraints.Is.Anything(), Rhino.Mocks.Constraints.Is.Anything(), Rhino.Mocks.Constraints.Is.Anything(), ...). Throw(new exception_ctor()); // We care about the passed-in arguments for CollaboratorService::methodName(). Expect.Call(stub.methodName(arg1, arg2, arg3, ...)).Throw(new exception_ctor());

RhinoMocks用于动态mock生成
准备工作	using NUnit.Framework; using Rhino.Mocks; [Test] public void [Feature]_[Scenario]_[ExpectedResult]() { MockRepository mockEngine = new MockRepository(); CollaboratorService mock = mockEngine.DynamicMock<CollaboratorService>(); ... mockEngine.ReplayAll(); ... }
设置期望: 一定不被调用	Expect.Call(() => { mock.methodName(dummy1, dummy2, ...); }).Repeat.Never();
设置期望: 不一定被调用	Expect.Call(() => { mock.methodName(dummy1, dummy2, ...); }).Repeat.Any();
设置期望: 一定被调用, 但不关心输入参数	Expect.Call(() => { mock.methodName(dummy1, dummy2, ...); }). Constraints(Rhino.Mocks.Constraints.Is.Anything(), Rhino.Mocks.Constraints.Is.Anything(), ...);
设置期望: 一定被调用, 并关心输入参数	Expect.Call(() => { mock.methodName(arg1, arg2, ...); });
设置期望: 一定被调用, 但不关心调用次序	Expect.Call(() => { mock.methodName1(arg1, arg2, ...); }); Expect.Call(() => { mock.methodName2(arg1, arg2, ...); });
设置期望: 一定被调用, 并关心调用次序	using (mockEngine.Ordered()) { Expect.Call(() => { mock.methodName1(arg1, arg2, ...); }); Expect.Call(() => { mock.methodName2(arg1, arg2, ...); }); }
显式验证	mockEngine.VerifyAll();