go: Add unit test for Execute()

appveyor.yml

@@ -48,7 +48,7 @@ build_script:
 
       go build ./bindings/go/evmc
       go generate ./bindings/go/evmc
-      go test ./bindings/go/evmc
+      go test -v ./bindings/go/evmc
     }
 
 after_build:

bindings/go/evmc/evmc_test.go

@@ -7,12 +7,16 @@
 package evmc
 
 import (
+	"bytes"
 	"testing"
+
+	"github.com/ethereum/go-ethereum/common"
 )
 
+var modulePath = "./example_vm.so"
+
 func TestLoad(t *testing.T) {
-	path := "./example_vm.so"
-	i, err := Load(path)
+	i, err := Load(modulePath)
 	if err != nil {
 		t.Fatal(err.Error())
 	}
@@ -24,3 +28,22 @@ func TestLoad(t *testing.T) {
 		t.Fatalf("version number is weird: %s", i.Version())
 	}
 }
+
+func TestExecute(t *testing.T) {
+	vm, _ := Load(modulePath)
+	defer vm.Destroy()
+
+	addr := common.Address{}
+	h := common.Hash{}
+	output, gasLeft, err := vm.Execute(nil, Byzantium, Call, false, 1, 999, addr, addr, nil, h, nil, h)
+
+	if bytes.Compare(output, []byte("Welcome to Byzantium!")) != 0 {
+		t.Errorf("execution unexpected output: %s", output)
+	}
+	if gasLeft != 99 {
+		t.Error("execution gas left is incorrect")
+	}
+	if err != Failure {
+		t.Error("execution returned unexpected error")
+	}
+}

examples/example_vm.c

@@ -91,6 +91,7 @@ static struct evmc_result execute(struct evmc_instance* instance,
         ret.output_data = (const uint8_t*)error;
         ret.output_size = strlen(error);
         ret.status_code = EVMC_FAILURE;
+        ret.gas_left = msg->gas / 10;
         ret.release = NULL;  // We don't need to release the constant messages.
         return ret;
     }