Vk: allow the allocated buffer memory to be larger in the test.

Fixes an assertion in Utility::copy() on NVidia.

src/Magnum/Vk/Test/BufferVkTest.cpp

@@ -228,11 +228,13 @@ void BufferVkTest::cmdCopyBuffer() {
 
     /* Source buffer */
     Buffer a{device(), BufferCreateInfo{BufferUsage::TransferSource, 7}, MemoryFlag::HostVisible};
-    Utility::copy("__ABCD_"_s, a.dedicatedMemory().map());
+    /* It might be allocated larger, copy to just a prefix */
+    Utility::copy("__ABCD_"_s, a.dedicatedMemory().map().prefix(7));
 
     /* Destination buffer, clear it to have predictable output */
     Buffer b{device(), BufferCreateInfo{BufferUsage::TransferDestination, 10}, MemoryFlag::HostVisible};
-    Utility::copy(".........."_s, b.dedicatedMemory().map());
+    /* It might be allocated larger, copy to just a prefix */
+    Utility::copy(".........."_s, b.dedicatedMemory().map().prefix(10));
 
     cmd.begin()
        .copyBuffer({a, b, {{2, 5, 4}}})
@@ -242,7 +244,8 @@ void BufferVkTest::cmdCopyBuffer() {
        .end();
     queue().submit({SubmitInfo{}.setCommandBuffers({cmd})}).wait();
 
-    CORRADE_COMPARE(arrayView(b.dedicatedMemory().mapRead()),
+    /* It might be allocated larger, compare just a prefix */
+    CORRADE_COMPARE(arrayView(b.dedicatedMemory().mapRead()).prefix(10),
         ".....ABCD."_s);
 }
 

src/Magnum/Vk/Test/MeshVkTest.cpp

@@ -329,9 +329,9 @@ void MeshVkTest::cmdDrawIndexed() {
         Containers::Array<char, MemoryMapDeleter> data = buffer.dedicatedMemory().map();
         /** @todo ffs fucking casts!!! */
         Utility::copy(Containers::stridedArrayView(QuadData).slice(&Quad::position),
-            Containers::arrayCast<Vector3>(data.slice(32, 32 + 12*4)));
+            Containers::arrayCast<Vector3>(data.sliceSize(32, 12*4)));
         Utility::copy(Containers::arrayCast<const char>(QuadIndexData),
-            Containers::stridedArrayView(data).exceptPrefix(32 + 12*4));
+            Containers::stridedArrayView(data).sliceSize(32 + 12*4, 12));
         mesh.addVertexBuffer(0, buffer, 32)
             .setIndexBuffer(Utility::move(buffer), 32 + 12*4, MeshIndexType::UnsignedShort)
             .setCount(6);