Use a custom Fuel cache location for tests (#213)

This ensures that tests are repeatable and are not affected by preexisting
models in the regular user's cache.

Signed-off-by: Addisu Z. Taddese <[email protected]>

src/SdfGenerator_TEST.cc

@@ -39,6 +39,8 @@
 #include "ignition/gazebo/components/World.hh"
 #include "ignition/gazebo/test_config.hh"
 
+#include "helpers/UniqueTestDirectoryEnv.hh"
+
 #include "SdfGenerator.hh"
 
 using namespace ignition;
@@ -142,9 +144,14 @@ class ElementUpdateFixture : public ::testing::Test
   {
     ignition::common::Console::SetVerbosity(4);
 
+    fuel_tools::ClientConfig config;
+    config.SetCacheLocation(test::UniqueTestDirectoryEnv::Path());
+    this->fuelClient = std::make_unique<fuel_tools::FuelClient>(config);
+
     auto fuelCb = [&](const std::string &_uri)
     {
-      auto out = fuel_tools::fetchResource(_uri);
+      auto out =
+          fuel_tools::fetchResourceWithClient(_uri, *this->fuelClient.get());
       if (!out.empty())
       {
         this->includeUriMap[out] = _uri;
@@ -195,6 +202,7 @@ class ElementUpdateFixture : public ::testing::Test
   public: std::unique_ptr<SdfEntityCreator> creator;
   public: msgs::SdfGeneratorConfig sdfGenConfig;
   public: sdf_generator::IncludeUriMap includeUriMap;
+  public: std::unique_ptr<fuel_tools::FuelClient> fuelClient;
 };
 
 /////////////////////////////////////////////////
@@ -854,3 +862,13 @@ TEST_F(GenerateWorldFixture, ModelsInline)
     EXPECT_TRUE(isSubset(this->root.Element(), newRoot.Element()));
   }
 }
+
+/////////////////////////////////////////////////
+/// Main
+int main(int _argc, char **_argv)
+{
+  ::testing::InitGoogleTest(&_argc, _argv);
+  ::testing::AddGlobalTestEnvironment(
+      new test::UniqueTestDirectoryEnv("sdf_gen_test_cache"));
+  return RUN_ALL_TESTS();
+}

test/helpers/UniqueTestDirectoryEnv.hh

@@ -0,0 +1,101 @@
+/*
+ * Copyright (C) 2020 Open Source Robotics Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+#ifndef IGNITION_GAZEBO_TEST_HELPERS_CUSTOMCACHEENV_HH_
+#define IGNITION_GAZEBO_TEST_HELPERS_CUSTOMCACHEENV_HH_
+
+#include <gtest/gtest.h>
+
+#include <ignition/common/Console.hh>
+#include <ignition/common/Filesystem.hh>
+#include <ignition/gazebo/test_config.hh>
+
+namespace ignition
+{
+namespace gazebo
+{
+namespace test
+{
+/// \brief Helper class to be used in internal tests. It sets up a unique test
+/// directory inside the cmake build directory (PROJECT_BINARY_PATH). The name
+/// of the directory is specified in the constructor argument, but if another
+/// directory with the same name is found, a new one with a numeric suffix will
+/// be created ensuring that the new name is unique. This class can
+/// be used, for example, for setting custom cache locations for tests that
+/// download Fuel models.
+///
+/// An instance of the Environment has to be added to gtest using the
+/// `::testing::AddGlobalTestEnvironment` function.
+///
+/// ## Usage
+///
+///  // In the test file
+///  int main(int _argc, char **_argv)
+///  {
+///    ::testing::InitGoogleTest(&_argc, _argv);
+///    ::testing::AddGlobalTestEnvironment(
+///      new ignition::gazebo::test::UniqueTestDirectoryEnv("custom_dir_name"));
+///     return RUN_ALL_TESTS();
+///  }
+/// gtest is responsible for the instance, so there is no need to delete it.
+class UniqueTestDirectoryEnv : public ::testing::Environment
+{
+  /// \brief Constructor
+  /// \param[in] _dirName Directory name based on which a unique path is created
+  public: explicit UniqueTestDirectoryEnv(const std::string &_dirName)
+  {
+    // We don't assert here because the assertion in the constructor won't be
+    // caught by gtest.
+    if (_dirName.empty())
+    {
+      ignerr << "_dirName cannot be empty\n";
+    }
+    else
+    {
+      UniqueTestDirectoryEnv::Path() = common::uniqueDirectoryPath(
+          common::joinPaths(PROJECT_BINARY_PATH, _dirName));
+    }
+  }
+
+  public: void SetUp() override
+  {
+    ASSERT_FALSE(UniqueTestDirectoryEnv::Path().empty())
+        << "UniqueTestDirectoryEnv is not configured properly";
+
+    common::createDirectory(UniqueTestDirectoryEnv::Path());
+    ASSERT_TRUE(common::exists(UniqueTestDirectoryEnv::Path()));
+  }
+
+  public: void TearDown() override
+  {
+    if (!UniqueTestDirectoryEnv::Path().empty())
+    {
+      common::removeAll(UniqueTestDirectoryEnv::Path());
+      UniqueTestDirectoryEnv::Path() = "";
+    }
+  }
+
+  public: static std::string &Path()
+  {
+    static std::string dirPath = "";
+    return dirPath;
+  }
+};
+}
+}
+}
+#endif
+