Fix RenderingIface_TEST for ogre2 when there is no display (#1098)

Signed-off-by: Ian Chen <[email protected]>
(cherry picked from commit 52ac1de)

Author: iche033

src/RenderEngineManager.cc

@@ -306,6 +306,18 @@ void RenderEngineManager::UnregisterEngine(const std::string &_name)
   std::lock_guard<std::recursive_mutex> lock(this->dataPtr->enginesMutex);
   auto iter = this->dataPtr->engines.find(_name);
 
+  if (iter == this->dataPtr->engines.end())
+  {
+    // Check if the provided name is a name of a default engine, if so,
+    // translate the name to the shared library name
+    auto defaultIt = this->dataPtr->defaultEngines.find(_name);
+    if (defaultIt != this->dataPtr->defaultEngines.end())
+      iter = this->dataPtr->engines.find(defaultIt->second);
+
+    if (iter == this->dataPtr->engines.end())
+      gzerr << "No render-engine registered with name: " << _name << std::endl;
+  }
+
   if (iter != this->dataPtr->engines.end())
   {
     this->dataPtr->UnregisterEngine(iter);

test/common_test/RenderingIface_TEST.cc

@@ -122,14 +122,19 @@ TEST(RenderingIfaceTest, RegisterEngine)
   if (count == 0)
     return;
 
-  // unregister existing engine by index
-  RenderEngine *eng = engine(0u);
+  RenderEngine *eng = nullptr;
+  std::string engineToTest = "";
+  if (gz::utils::env(kEngineToTestEnv, engineToTest))
+    eng = engine(engineToTest);
+  else
+    eng = engine(0u);
+
   ASSERT_NE(nullptr, eng);
   auto engineName = eng->Name();
   ASSERT_FALSE(engineName.empty());
 
   EXPECT_TRUE(hasEngine(engineName));
-  EXPECT_NO_THROW(unregisterEngine(0u));
+  EXPECT_NO_THROW(unregisterEngine(engineName));
   EXPECT_FALSE(hasEngine(engineName));
 
   // register engine back with a different name