Setting up googlemock with Visual C++ 2010 Express Edition

Following on from my last post about setting up googletest to use with Visual Studio 2010 express edition, this post builds on that by showing how to build, setup and test the googlemock libraries.

If you have read the previous post, then the basic steps are very similar.

First, download the googlemock zip file and unzip it to known location. As before, I suggest something easy, either C:\gmock-1.6.0, or as in my case C:\src\gmock-1.6.0. One useful fact is that all the gtest code is included as part of the gmock distribution. It can be found at \gmock-1.6.0\gtest.

Building the gtest libraries

It is the same process as build the gtest libraries. One importany note is that

The gmock libraries contain all the gtest code as well.

Navigate to the directory \gmock-1.6.0\msvc\2010 and open the Visual C++ project gmock (gmock.sln). You will end up with three projects.

image

Go ahead and build these (F7) and ignore any warnings. Once successfully built, look in the directory \gmock-1.6.0\msvc\2010\gtest\Debug and you will find two library files

  • gmock.lib
  • gmock_main.lib

Test the GMock Library

As part of the standard build two executable are created that allow a quick self-test of googlemock (gtest does have the same but I neglected to mention those in my previous post).

I recommend opening a command window and navigating to directory  \gmock-1.6.0\msvc\2010\Debug. There you will fine the file gmock_test.exe; go ahead and execute that [NOTE: I had two (of the 830) tests fail, which I’m not sure why (yet) – to be investigated]

image
This indicates that (most of) gmock functions correctly.

Building a Base GMock Project

A gmock project is the same as  a gtest project but with different project properties. Create a newWin32 Console Application  project.  Add a test fixture file to the project:

testFixture.cpp
  1. #include “gtest/gtest.h”
  2. TEST(setup_test_case, testWillPass)
  3. {
  4.     EXPECT_EQ(42, 42);
  5. }
  6. TEST(setup_test_case, testWillFail)
  7. {
  8.     EXPECT_EQ(42, 0);
  9. }

and exclude file containing default main from build.

Modify the project properties (Alt+F7) as follows:

  • Set gmock and gtest header include directories
    • C/C++ -> General -> Additional Include Directories
      • \gmock-1.6.0\include
      • \gmock-1.6.0\gtest\include
  • Add gmock libraries (instead of gtest libs)
    • Linker -> General -> Addition Library Directories
      • \gmock-1.6.0\msvc\2010\Debug
    • Linker -> Input -> Additional Dependencies
      • gmock.lib
      • gmock_main.lib
  • Modify Runtime Library:
    • C/C++ -> Code Generation -> Runtime Library
      • Multi-threaded Debug (/MTd).

Note here that we don’t have to include the gtest libraries as these are embedded in the gmock libraries. Build and run and we will see the familiar gtest output:
image

To test the gmock setup we need to create two classes:

  • The class to become the Unit-Under-Test (UUT)
  • An interface class that the UUT calls upon, which doesn’t have any implementation (or the implementation is target/hardware specific).

Interface Class

IWidget.h
  1. class IWidget
  2. {
  3. public:
  4.     virtual void On() = 0;
  5.     virtual void Off() = 0;
  6. };

Unit Under Test

WidgetController.h
  1. class IWidget;
  2. class WidgetController
  3. {
  4. public:
  5.     WidgetController(IWidget& w);
  6.     ~WidgetController(void);
  7.     void exec();
  8. private:
  9.     IWidget& myWidget;
  10. };
WidgetController.cpp
  1. #include “WidgetController.h”
  2. #include “IWidget.h”
  3. WidgetController::WidgetController(IWidget& w):myWidget(w)
  4. {
  5.     myWidget.Off();
  6. }
  7. WidgetController::~WidgetController()
  8. {
  9.     myWidget.Off();
  10. }
  11. void WidgetController::exec()
  12. {
  13.     myWidget.On();
  14. }

Testing using the Mock framework

To test using the Mock we need to:

  1. Include the gmock header [line 3]
  2. Create a mock class derived from the Interface class [lines 7-12]
  3. Create a test where the UUT calls on the interface on the mock object [lines 16-23]
  4. Set the mock objects expectation [line 20]. The mock expectation is that the Off member function will be called twice, once during WidgetController construction and once during destruction.
Using the mock
  1. // testFixture.cpp
  2. #include “gtest/gtest.h”
  3. #include “gmock/gmock.h”
  4. #include “IWidget.h”
  5. class MockWidget : public IWidget
  6. {
  7. public:
  8.     MOCK_METHOD0(On, void());
  9.     MOCK_METHOD0(Off, void());
  10. };
  11. #include “WidgetController.h”
  12. TEST(TestWidgetController, testConstructor)
  13. {
  14.     MockWidget mw;
  15.     EXPECT_CALL(mw, Off()).Times(2);
  16.     WidgetController wc(mw);
  17. }

Build and run

image

You can see gmock in action by simply changing the expectation, e.g. [line 6]

Failing Test
  1. TEST(TestWidgetController, testConstructor)
  2. {
  3.     MockWidget mw;
  4. //    EXPECT_CALL(mw, Off()).Times(2);
  5.     EXPECT_CALL(mw, Off());
  6.     WidgetController wc(mw);
  7. }

will result in the following failed test output:

image

Where next?

Once you have a working project, the documentation on the Googlemock site is excellent. Start with Googlemock for Dummies.

Posted on March 15th, 2012
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1 Comment a “Setting up googlemock with Visual C++ 2010 Express Edition”

  1. Chris says:

    Oof. I’ve been thinking about moving (part of) our group to a dual-target, test-as-you-go kinda system rather than our current ad-hoc style.

    I’m a little worried about the first couple times we try it because I know setting up the dual-target environment is going to be time consuming, but I’m sick of finding missed corner cases 3 months into hardware integration where they start pushing the schedule out.

    Thanks for the link to the Grenning book, the excerpts look like they have some good advice to get me started.

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