Before you begin, install VisualGDB 5.6 or later and make sure you are using the Custom edition or higher.<\/p>\n
- \n
- Start Visual Studio and locate the VisualGDB Linux Project Wizard under the File->New Project<\/strong> dialog:
![\"\"](\"https:\/\/visualgdb.com\/w\/wp-content\/uploads\/2021\/11\/01-newprj-1.png\")
<\/a><\/li>\n- Enter the name and location for your project:
![\"\"](\"https:\/\/visualgdb.com\/w\/wp-content\/uploads\/2021\/11\/02-mock.png\")
<\/a><\/li>\n- On the Project Type<\/strong> page select “Create a new project -> Unit Test -> CMake<\/strong>“, then select the GoogleTest<\/strong> framework below:
![\"\"](\"https:\/\/visualgdb.com\/w\/wp-content\/uploads\/2021\/11\/03-test.png\")
<\/a><\/li>\n- Select the computer where you would like to build and run the test and press “Next<\/strong>” to continue:
![\"\"](\"https:\/\/visualgdb.com\/w\/wp-content\/uploads\/2021\/11\/04-machine.png\")
<\/a><\/li>\n- As you are using the Advanced CMake, VisualGDB can directly access the source files on the Linux machine via SSH. However, as this tutorial is checked into Git<\/a> together with the project file, we will store the sources on the Windows side and will upload them during build:
![\"\"](\"https:\/\/visualgdb.com\/w\/wp-content\/uploads\/2021\/11\/05-src.png\")
<\/a><\/li>\n- Press “Finish” to create a basic Unit Test project. Build it by pressing Ctrl-Shift-B and run the tests via Test Explorer. The FailingTest<\/strong> should immediately fail, while the other tests should succeed:
![\"\"](\"https:\/\/visualgdb.com\/w\/wp-content\/uploads\/2021\/11\/06-tests.png\")
<\/a><\/li>\n- Now we will add a basic Vector struct. Add the following code to the main file, then press Ctrl+.<\/strong> and\u00a0 select “Run a RefactorScript -> Generate a constructor”:\n
struct Vector\r\n{\r\n double X, Y;\r\n};<\/pre>\n![\"\"](\"https:\/\/visualgdb.com\/w\/wp-content\/uploads\/2021\/11\/07-ctor.png\")
<\/a>VisualGDB will automatically generate a constructor for the Square class based on the existing fields:<\/p>\n\u00a0 Vector(double x, double y)\r\n \t\t: X(x)\r\n \t\t, Y(y)\r\n {\r\n }<\/pre>\nSee our RefactorScript tutorial<\/a> for more details about generating constructors.<\/li>\n
- Now we will add the following code to the program:\n
- \n
- A Math<\/strong> class providing the Square()<\/strong> method.<\/li>\n
- A GetDistance()<\/strong> function computing the distance between 2 vectors using the Square()<\/strong> method.<\/li>\n
- A SquareTest()<\/strong> unit test checking that Square()<\/strong> function returns expected results for a single pair of inputs<\/li>\n<\/ul>\n
Add the following code to your main source file:<\/p>\n
class Math\r\n{\r\npublic:\r\n double Square(double arg)\r\n {\r\n return arg * arg;\r\n }\r\n};\r\n\r\ndouble GetDistance(Math *pMath, const Vector &a, const Vector &b)\r\n{\r\n return sqrt(pMath->Square(a.X - b.X) + pMath->Square(a.Y - b.Y));\r\n}\r\n\r\nTEST(DemoTestGroup, SquareTest)\r\n{\r\n Vector left(0, 0);\r\n Vector right(3, 4);\r\n Math math;\r\n double distance = GetDistance(&math, left, right);\r\n EXPECT_EQ(distance, 5);\r\n}<\/pre>\n<\/li>\n- Build the project and run the test, making sure it succeeds:
![\"\"](\"https:\/\/visualgdb.com\/w\/wp-content\/uploads\/2021\/11\/09-iface.png\")
<\/a><\/li>\n- The current version of the test checks that the GetDistance()<\/strong> function returned the correct result, but it doesn’t check how many times it calls the Square()<\/strong> method and with what arguments. We will now do exactly that – replace the real Math<\/strong> class with a Mock<\/strong> class that counts how many times Square() was called. However, before we can do that, Math needs to be refactored into the IMath<\/strong> interface and a Math<\/strong> class implementing it:\n
class IMath\r\n{\r\npublic:\r\n virtual double Square(double arg) = 0;\r\n};\r\n\r\nclass Math : public IMath\r\n{\r\npublic:\r\n double Square(double arg) override\r\n {\r\n return arg * arg;\r\n }\r\n};<\/pre>\n<\/li>\n- Go to the IMath<\/strong> class, press “Ctrl+.” and select “Run a RefactorScript -> Generate a mock class”:
![\"\"](\"https:\/\/visualgdb.com\/w\/wp-content\/uploads\/2021\/11\/10-genmock.png\")
<\/a><\/li>\n- VisualGDB will automatically generate a mock class for the IMath<\/strong> interface using the GoogleMock<\/strong> syntax:
![\"\"](\"https:\/\/visualgdb.com\/w\/wp-content\/uploads\/2021\/11\/11-gen.png\")
<\/a>Press “Copy and close”, insert the generated mock class in the main source file and update it to inherit the IMath<\/strong> interface.<\/li>\n- Finally, include the <gmock\/gmock.h><\/strong> file and update the SquareTest<\/strong> unit test as shown below:\n
TEST(DemoTestGroup, SquareTest)\r\n{\r\n Vector left(0, 0);\r\n Vector right(3, 4);\r\n MockIMath math;\r\n\r\n EXPECT_CALL(math, Square(3)).WillOnce(Return(9));\r\n EXPECT_CALL(math, Square(4)).WillOnce(Return(16));\r\n\r\n double distance = GetDistance(&math, left, right);\r\n EXPECT_EQ(distance, 5);\r\n}<\/pre>\nNote that EXPECT_CALL()<\/strong> macros. They configure the MockIMath<\/strong> instance to verify that it’s being called with certain arguments, and to return the specified values. You can read more about GoogleMock syntax on this page<\/a>.<\/li>\n
- Run the test. It will now fail with a detailed message explaining that Square()<\/strong> was called the arg=-3<\/strong> that doesn’t match neither 3<\/strong> nor 4<\/strong>:
![\"\"](\"https:\/\/visualgdb.com\/w\/wp-content\/uploads\/2021\/11\/12-fail.png\")
<\/a><\/li>\n- Update the EXPECT_CALL()<\/strong> macros to expect the values of -3<\/strong> and -4<\/strong> respectively. The test will now pass:
![\"\"](\"https:\/\/visualgdb.com\/w\/wp-content\/uploads\/2021\/11\/13-pass.png\")
<\/a><\/li>\n- You can tweak the code produced by RefactorScripts by directly editing the script. VisualGDB will immediately update the output. E.g. change first 2 lines of the DoGenerateMockClass()<\/strong> generator to automatically strip “I” from the class name and to inherit the interface:\n
set strippedName = class.ShortName.StripPrefix(\"I\");\r\n>class Mock$strippedName : public $class.QualifiedName<\/pre>\n
![\"\"](\"https:\/\/visualgdb.com\/w\/wp-content\/uploads\/2021\/11\/14-strip.png\")
<\/a><\/li>\n- The GenerateMockClass<\/strong> script can automatically append the const<\/strong> qualifier for the const methods, however it won’t automatically add the override<\/strong> keyword. To change this, locate the logic for outputting “(const)” near the end of the generator and replace it with the following:\n
if (method.IsConst || method.IsVirtual)\r\n{\r\n\t>>, (\r\n\tif (method.IsConst)\r\n\t\t>>const\r\n\tif (method.IsConst && method.IsVirtual)\r\n\t\t>>, \r\n\tif (method.IsVirtual)\r\n\t\t>>override\r\n\t>>)\r\n}<\/pre>\nNow all virtual methods will be marked as “(override)”:
![\"\"](\"https:\/\/visualgdb.com\/w\/wp-content\/uploads\/2021\/11\/15-override-1.png\")
<\/a><\/li>\n- Press “Copy and close” to copy the updated mock class into the Clipboard so that you can replace the original implementation:
![\"\"](\"https:\/\/visualgdb.com\/w\/wp-content\/uploads\/2021\/11\/16-mock2.png\")
<\/a><\/li>\n<\/ol>\n","protected":false},"excerpt":{"rendered":"This tutorial shows how to use VisualGDB with the GoogleTest\/GoogleMock framework to verify the behavior of algorithms in your code<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[128],"tags":[52,240,238,129],"_links":{"self":[{"href":"https:\/\/visualgdb.com\/w\/wp-json\/wp\/v2\/posts\/7662"}],"collection":[{"href":"https:\/\/visualgdb.com\/w\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/visualgdb.com\/w\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/visualgdb.com\/w\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/visualgdb.com\/w\/wp-json\/wp\/v2\/comments?post=7662"}],"version-history":[{"count":1,"href":"https:\/\/visualgdb.com\/w\/wp-json\/wp\/v2\/posts\/7662\/revisions"}],"predecessor-version":[{"id":7679,"href":"https:\/\/visualgdb.com\/w\/wp-json\/wp\/v2\/posts\/7662\/revisions\/7679"}],"wp:attachment":[{"href":"https:\/\/visualgdb.com\/w\/wp-json\/wp\/v2\/media?parent=7662"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/visualgdb.com\/w\/wp-json\/wp\/v2\/categories?post=7662"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/visualgdb.com\/w\/wp-json\/wp\/v2\/tags?post=7662"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
- A GetDistance()<\/strong> function computing the distance between 2 vectors using the Square()<\/strong> method.<\/li>\n
- Enter the name and location for your project: