How to use MockSupportPlugin in CppUTest to perform checkExpectations automatically?

Question

CppUTest documentations says

MockSupportPlugin makes the work with mocks easier. It does the following work for you automatically:

• checkExpectations at the end of every test (on global scope, which goes recursive over all scopes)
• clear all expectations at the end of every test
• install all comparators that were configured in the plugin at the beginning of every test
• remove all comparators at the end of every test

ref: https://cpputest.github.io/plugin_manual.html

I tried the following example:

#include "CppUTest/TestRegistry.h"
#include "CppUTestExt/MockSupportPlugin.h"

MyDummyComparator dummyComparator;
MockSupportPlugin mockPlugin;

mockPlugin.installComparator("MyDummyType", dummyComparator);
TestRegistry::getCurrentRegistry()->installPlugin(&mockPlugin);

with my added MYDummyComparator:

class MyDummyComparator : public MockNamedValueComparator
{
   bool isEqual( const void *object1, const void *object2 )
   {
      return object1 == object2;
   }

   SimpleString valueToString( const void *object )
   {
      return SimpleString();
   }
} dummyComparator;

But when I remove expectOneCall() or expectNCalls() from my tests, it shows the tests failed. How do I use MockSupportPlugin from CPPUTest to achieve doing "checkExpectations at the end of every test (on global scope, which goes recursive over all scopes)" automatically?

Answer 1

The mock type comparators would be used in your mock comparisons.

For example, you need to compare a struct of type Point , which looks like this:

struct Point {
    int    x;
    int    y;
};

You would define your comparator like this:

class PointTypeComparator : public MockNamedValueComparator
{
public:
    bool isEqual(const void* object1, const void* object2) override
    {
        // Casting here the void pointers to the type to compare
        const auto *pointObject1 = (const Point *) object1; 
        const auto *pointObject2 = (const Point *) object2;

        // Perform comparison, in this case, comparing x and y
        return ((pointObject1->x == pointObject2->x)
                && (pointObject1->y == pointObject2->y);
    }
    virtual SimpleString valueToString(const void* object)
    {
        return (char *) "string";
    }
};

Next, within you test group, you need to install these comparators in the setup and also in the teardown clear them:

TEST_GROUP(MyTest)
{
    void setup()
    {
        PointTypeComparator pointComparator;
        mock().installComparator("Point *", pointComparator);  // Note, its a pointer to a Point type
    }

    void teardown()
    {
        // Call check expectations here, and also clear all comparators after that
        mock().checkExpectations();
        mock().clear();
        mock().removeAllComparatorsAndCopiers();
    }
};

Next, you can use this Comparator, using the withParameterOfType function as:

mock().expectOneCall("foo")
    .withParameterOfType("Point *", "name", &address); // Here name is the name of variable, and &address is the address of the Point type variable.