add a clCreateContext test with an empty device vector

Author: bashbaug

tests/test_openclhpp.cpp

@@ -535,6 +535,40 @@ void testMoveConstructContextNonNull(void);
 void testMoveConstructContextNull(void);
 MAKE_MOVE_TESTS(Context, make_context, clReleaseContext, contextPool)
 
+static cl_context clCreateContext_testEmptyDevices(
+    const cl_context_properties* properties,
+    cl_uint num_devices,
+    const cl_device_id* devices,
+    void (CL_CALLBACK* pfn_notify)(const char* errinfo, const void* private_info, size_t cb, void* user_data),
+    void* user_data,
+    cl_int* errcode_ret,
+    int num_calls)
+{
+    TEST_ASSERT_EQUAL(properties, nullptr);
+    TEST_ASSERT_EQUAL(num_devices, 0);
+    TEST_ASSERT_EQUAL(devices, nullptr);
+    TEST_ASSERT_EQUAL(pfn_notify, nullptr);
+    TEST_ASSERT_EQUAL(user_data, nullptr);
+
+    if (errcode_ret) {
+        errcode_ret[0] = CL_INVALID_VALUE;
+    }
+
+    return nullptr;
+}
+
+void testContextCreateEmptyDevices(void)
+{
+#ifndef CL_HPP_ENABLE_EXCEPTIONS
+    clCreateContext_StubWithCallback(clCreateContext_testEmptyDevices);
+
+    cl::vector<cl::Device> vec;
+    cl::Context context(vec);
+
+    TEST_ASSERT_EQUAL(nullptr, context());
+#endif
+}
+
 /// Stub for querying CL_CONTEXT_DEVICES that returns two devices
 static cl_int clGetContextInfo_testContextGetDevices(
     cl_context context,