Add wasmer config SetTestVersion method

lib/runtime/wasmer/config.go

@@ -4,6 +4,8 @@
 package wasmer
 
 import (
+	"testing"
+
 	"github.com/ChainSafe/gossamer/internal/log"
 	"github.com/ChainSafe/gossamer/lib/common"
 	"github.com/ChainSafe/gossamer/lib/keystore"
@@ -23,3 +25,14 @@ type Config struct {
 	CodeHash    common.Hash
 	testVersion *runtime.Version
 }
+
+// SetTestVersion sets the test version for the runtime.
+// WARNING: This should only be used for testing purposes.
+// The *testing.T argument is only required to enforce this function
+// to be used in tests only.
+func (c *Config) SetTestVersion(t *testing.T, version runtime.Version) {
+	if t == nil {
+		panic("*testing.T argument cannot be nil. Please don't use this function outside of Go tests.")
+	}
+	c.testVersion = &version
+}