I'm working on some tests so that I can refactor an old C++ project. I'm trying to match two arrays using the gmock matcher ElementsAreArray().
EXPECT_THAT(value_instance.value, ::testing::ElementsAreArray(var_array));
where value_instance.value is a pointer to a C array.
However when I compile with this line of code in my test I get the following error output from the gmock-matchers.h file:
Error 1 error C2510: 'type' : left of '::' must be a class/struct/union s:\repo_file\gmock-1.6.0\include\gmock\gmock-matchers.h 2535 1 Project_Tests
Error 2 error C2146: syntax error : missing ';' before identifier 'Element' s:\repo_file\gmock-1.6.0\include\gmock\gmock-matchers.h 2536 1 Project_Tests
Error 3 error C4430: missing type specifier - int assumed. Note: C++ does not support default-int s:\repo_file\gmock-1.6.0\include\gmock\gmock-matchers.h 2536 1 Project_Tests
Error 4 error C2065: 'Element' : undeclared identifier s:\repo_file\gmock-1.6.0\include\gmock\gmock-matchers.h 2536 1 Project_Tests
Error 5 error C2825: 'testing::internal::ElementsAreMatcherImpl<Container>::StlContainer': must be a class or namespace when followed by '::' s:\repo_file\gmock-1.6.0\include\gmock\gmock-matchers.h 2399 1 Project_Tests
Error 6 error C2039: 'value_type' : is not a member of '`global namespace'' s:\repo_file\gmock-1.6.0\include\gmock\gmock-matchers.h 2399 1 Project_Tests
Error 7 error C2146: syntax error : missing ';' before identifier 'Element' s:\repo_file\gmock-1.6.0\include\gmock\gmock-matchers.h 2399 1 Project_Tests
Error 8 error C4430: missing type specifier - int assumed. Note: C++ does not support default-int s:\repo_file\gmock-1.6.0\include\gmock\gmock-matchers.h 2399 1 Project_Tests
Error 9 error C4430: missing type specifier - int assumed. Note: C++ does not support default-int s:\repo_file\gmock-1.6.0\include\gmock\gmock-matchers.h 2502 1 Project_Tests
Error 10 error C2146: syntax error : missing ',' before identifier 'Element' s:\repo_file\gmock-1.6.0\include\gmock\gmock-matchers.h 2502 1 Project_Tests
Error 11 error C2065: 'Element' : undeclared identifier s:\repo_file\gmock-1.6.0\include\gmock\gmock-matchers.h 2502 1 Project_Tests
Error 12 error C2059: syntax error : '>' s:\repo_file\gmock-1.6.0\include\gmock\gmock-matchers.h 2502 1 Project_Tests
Error 13 error C2143: syntax error : missing ';' before '}' s:\repo_file\gmock-1.6.0\include\gmock\gmock-matchers.h 2506 1 Project_Tests
Error 14 error C1004: unexpected end-of-file found s:\repo_file\gmock-1.6.0\include\gmock\gmock-matchers.h 2506 1 Project_Tests
I'm probably missing something really silly but I can't seem to find the problem.
#include <cstring>
#include "gtest/gtest.h"
#include "gmock/gmock.h"
//This is a stripped down version of The Class under test
enum {
VAL_TYPE_UNKNOWN, VAL_TYPE_INT, VAL_TYPE_BOOL, VAL_TYPE_ARRAY
};
class ClassUnderTest
{
public:
int alloc_len;
int len;
int type;
long i_value;
unsigned char *value;
ClassUnderTest (void)
{
alloc_len = 0;
len = 0;
value = 0;
i_value = 0;
type = VAL_TYPE_INT;
}
~ClassUnderTest (void)
{
if (value)
{
delete [] value;
value = 0;
}
}
void Init (void *val, int v_len)
{
NewLength(v_len);
if (val)
memcpy(value, val, v_len);
type = VAL_TYPE_ARRAY;
}
void NewLength (int new_len)
{
unsigned char *old;
if ((new_len > alloc_len) || (new_len == 0))
{
old = value;
value = 0;
if (new_len > 0)
{
value = new unsigned char [new_len];
memset(value, 0, new_len);
}
alloc_len = new_len;
if (old)
{
if (value)
memcpy(value, old, len);
delete [] old;
}
}
else if (new_len > len)
memset(value+len, 0, new_len-len);
len = new_len;
}
}
//this fails with the error list above
TEST(ClassUnderTestTests, TestInit)
{
ClassUnderTest value_instance;
unsigned char var_array[] = {1, 2, 3, 4, 5};
value_instance.Init((void *)var_array, sizeof(var_array));
EXPECT_EQ(value_instance.len, sizeof(var_array));
EXPECT_EQ(value_instance.i_value, 0);
EXPECT_EQ(value_instance.type, VAL_TYPE_ARRAY);
EXPECT_THAT(value_instance.value, testing::ElementsAreArray(var_array));
}
//This example works However the code above does not
TEST(ClassUnderTestTests, ElementsAreArrayFailure)
{
int array1[] = {1, 2, 3, 4, 5};
int array2[] = {1, 2, 3, 4, 5};
EXPECT_THAT(array1, testing::ElementsAreArray(array2));
}
int main(int argc, char **argv) {
::testing::InitGoogleTest(&argc, argv);
return RUN_ALL_TESTS();
}
You need to dereference the pointer to the C-array.
EXPECT_THAT(*value_instance.value, ::testing::ElementsAreArray(var_array));
// ^--- dereference the C-array
OK, having seen your code now, I'd say that value_instance.value is a dynamically-allocated array rather than a pointer to a C array (see comp.lang.c FAQ on Arrays and Pointers).
So the simple fix is to swap the arguments in the EXPECT_THAT(value, matcher) macro. The value can't just be a pointer in this case, you need to give it a std::-like container (e.g. a C array). However, the ElementsAreArray function can handle being passed a dynamically-allocated array, assuming you also pass it the size of the array (since it can't be deduced).
EXPECT_THAT(var_array,
testing::ElementsAreArray(value_instance.value, value_instance.len));
Rather than swapping the order of the arguments to EXPECT_THAT, you could alternatively construct a temporary vector from value_instance.value and pass that as the value:
std::vector<unsigned char> value_copy(value_instance.value,
value_instance.value + value_instance.len);
EXPECT_THAT(value_copy, testing::ElementsAreArray(var_array));