cpp: Add VM::has_capability() method

CHANGELOG.md

@@ -41,6 +41,8 @@ removed.
   the Host context and interface parameters. This is useful for Precompiles VMs
   that do not interact with the Host.
   [#302](https://github.com/ethereum/evmc/pull/302)
+- In C++ API, the `VM::has_capability()` method has been added.
+  [#465](https://github.com/ethereum/evmc/pull/465)
 
 ### Changed
 

include/evmc/evmc.hpp

@@ -570,6 +570,12 @@ class VM
     /// @copydoc evmc_vm::version
     char const* version() const noexcept { return m_instance->version; }
 
+    /// Checks if the VM has the given capability.
+    bool has_capability(evmc_capabilities capability) const noexcept
+    {
+        return (get_capabilities() & static_cast<evmc_capabilities_flagset>(capability)) != 0;
+    }
+
     /// @copydoc evmc::vm::get_capabilities
     evmc_capabilities_flagset get_capabilities() const noexcept
     {

test/unittests/test_cpp.cpp

@@ -314,8 +314,18 @@ TEST(cpp, vm)
     const auto host = evmc_host_interface{};
     auto res = vm.execute(host, nullptr, EVMC_MAX_REVISION, {}, nullptr, 0);
     EXPECT_EQ(res.status_code, EVMC_FAILURE);
+}
+
+TEST(cpp, vm_capabilities)
+{
+    const auto vm = evmc::VM{evmc_create_example_vm()};
 
     EXPECT_TRUE(vm.get_capabilities() & EVMC_CAPABILITY_EVM1);
+    EXPECT_TRUE(vm.get_capabilities() & EVMC_CAPABILITY_EWASM);
+    EXPECT_FALSE(vm.get_capabilities() & EVMC_CAPABILITY_PRECOMPILES);
+    EXPECT_TRUE(vm.has_capability(EVMC_CAPABILITY_EVM1));
+    EXPECT_TRUE(vm.has_capability(EVMC_CAPABILITY_EWASM));
+    EXPECT_FALSE(vm.has_capability(EVMC_CAPABILITY_PRECOMPILES));
 }
 
 TEST(cpp, vm_set_option)