CODEWITHSUNDEEP
c++googletestgooglemock
ZeroPhase
ZeroPhase

Reputation: 647

How to solve gmock EXPECT_CALL failure, when variable passed to function doesn't matter

I had EXPECT_CALL passing on my tests, until I added a header to wrap the unsigned char * I was testing for. I understand that the test is falling, since it isn't the same unsigned char * as expected. I'm just not sure how to redesign my tests, so the unsigned char * assigned to causes the test to pass.

My test(With initialization of variables left out):

EXPECT_CALL(networkConnectionMock, Transmit(packetData, dataSize));

packetManager.Update(0.01f);
packetManager.Send(packetData, dataSize);

The function under test:

void PacketManager::Send(unsigned char *packetData, int packetSize)
{
    if(this->secondSinceLastUpdate <= 1.0f)
        packetsSent++;
    else
    {
        packetsSent = 0;
        this->secondSinceLastUpdate = 0.0f;
    }

    std::stringstream convert;
    convert << htonl((uint32_t)packetSize);
    Header *header = new Header;
    header->name = "PKT_" + convert.str();
    header->packetSize = packetSize;
    header->packetData = packetData;
    unsigned char * pktHeader = new unsigned char[sizeof(Header)];
    pktHeader = (unsigned char*)header;
    PKT_Header = pktHeader; // tried assigning to public variable, 
                           // but would be assigned to after EXPECT_CALL is setup.
    int totalPacketSize = packetSize; // rewrite to loop through que
    if(header->packetSize <= 800 && totalPacketSize <= 1024 && packetsSent <= 30)
        networkConnection->Transmit(pktHeader, packetSize);
}

gmock output:

[==========] Running 1 test from 1 test case.
[----------] Global test environment set-up.
[----------] 1 test from PacketManager
[ RUN      ] PacketManager.SendsPacketsUnder1024
unknown file: Failure

Unexpected mock function call - returning directly.
    Function call: Transmit(0x2096c10, 100)
Google Mock tried the following 1 expectation, but it didn't match:

/home/zerophase/ClionProjects/PacketManager/tests/basic_tests/basic_check.cpp:20: EXPECT_CALL(networkConnectionMock, Transmit(packetData, dataSize))...
  Expected arg #0: is equal to 0x2096560
           Actual: 0x2096c10
         Expected: to be called once
           Actual: never called - unsatisfied and active
/home/zerophase/ClionProjects/PacketManager/tests/basic_tests/basic_check.cpp:20: Failure
Actual function call count doesn't match EXPECT_CALL(networkConnectionMock, Transmit(packetData, dataSize))...
         Expected: to be called once
           Actual: never called - unsatisfied and active
[  FAILED  ] PacketManager.SendsPacketsUnder1024 (0 ms)
[----------] 1 test from PacketManager (0 ms total)

[----------] Global test environment tear-down
[==========] 1 test from 1 test case ran. (0 ms total)
[  PASSED  ] 0 tests.
[  FAILED  ] 1 test, listed below:
[  FAILED  ] PacketManager.SendsPacketsUnder1024

Is EXPECT_CALL still what I want to use to test for Transmit being called?

Upvotes: 1

Views: 3667

Answers (2)

Antonio P&#233;rez
Antonio P&#233;rez

Reputation: 6982

You are trying to match the call to Transmit with packetData as first parameter, but the call being made in PacketManager::Send is for pktHeader, which is a (leaking) local variable. The mock correctly reports unmatched function call, and must also report a warning for uninteresting function call.

Upvotes: 0

Mohamad Elghawi
Mohamad Elghawi

Reputation: 2124

If you don't really care about the exact parameter being passed to Transmit then you can use the _ keyword.

EXPECT_CALL(networkConnectionMock, Transmit(_, dataSize));

If you do care about the exact parameter then I would rearrange my code slightly so that instead of passing in a raw unsigned char* into Send, I would create a simple class that does the work you're doing in Send and have that class be responsible for returning an unsigned char*.

That way you can pass a mock object into your Send method which gives you more control over what parameters are passed into Trasmit.

Upvotes: 2

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