diff --git a/neuralnetworks/1.0/vts/functional/BasicTests.cpp b/neuralnetworks/1.0/vts/functional/BasicTests.cpp
index 5727ca4..551ea67 100644
--- a/neuralnetworks/1.0/vts/functional/BasicTests.cpp
+++ b/neuralnetworks/1.0/vts/functional/BasicTests.cpp
@@ -25,7 +25,7 @@
 
 // status test
 TEST_F(NeuralnetworksHidlTest, StatusTest) {
-    Return<DeviceStatus> status = device->getStatus();
+    Return<DeviceStatus> status = kDevice->getStatus();
     ASSERT_TRUE(status.isOk());
     EXPECT_EQ(DeviceStatus::AVAILABLE, static_cast<DeviceStatus>(status));
 }
@@ -33,7 +33,7 @@
 // initialization
 TEST_F(NeuralnetworksHidlTest, GetCapabilitiesTest) {
     Return<void> ret =
-            device->getCapabilities([](ErrorStatus status, const Capabilities& capabilities) {
+            kDevice->getCapabilities([](ErrorStatus status, const Capabilities& capabilities) {
                 EXPECT_EQ(ErrorStatus::NONE, status);
                 EXPECT_LT(0.0f, capabilities.float32Performance.execTime);
                 EXPECT_LT(0.0f, capabilities.float32Performance.powerUsage);
diff --git a/neuralnetworks/1.0/vts/functional/GeneratedTestHarness.cpp b/neuralnetworks/1.0/vts/functional/GeneratedTestHarness.cpp
index 33a6fa5..1948c05 100644
--- a/neuralnetworks/1.0/vts/functional/GeneratedTestHarness.cpp
+++ b/neuralnetworks/1.0/vts/functional/GeneratedTestHarness.cpp
@@ -122,9 +122,15 @@
 
 // Top level driver for models and examples generated by test_generator.py
 // Test driver for those generated from ml/nn/runtime/test/spec
-void EvaluatePreparedModel(const sp<IPreparedModel>& preparedModel, const TestModel& testModel) {
+void Execute(const sp<IDevice>& device, const TestModel& testModel) {
+    const Model model = createModel(testModel);
     const Request request = createRequest(testModel);
 
+    // Create IPreparedModel.
+    sp<IPreparedModel> preparedModel;
+    createPreparedModel(device, model, &preparedModel);
+    if (preparedModel == nullptr) return;
+
     // Launch execution.
     sp<ExecutionCallback> executionCallback = new ExecutionCallback();
     Return<ErrorStatus> executionLaunchStatus = preparedModel->execute(request, executionCallback);
@@ -143,53 +149,10 @@
 }
 
 // Tag for the generated tests
-class GeneratedTest : public GeneratedTestBase {
-  protected:
-    void Execute(const TestModel& testModel) {
-        Model model = createModel(testModel);
-
-        // see if service can handle model
-        bool fullySupportsModel = false;
-        Return<void> supportedCall = device->getSupportedOperations(
-                model, [&fullySupportsModel](ErrorStatus status, const hidl_vec<bool>& supported) {
-                    ASSERT_EQ(ErrorStatus::NONE, status);
-                    ASSERT_NE(0ul, supported.size());
-                    fullySupportsModel = std::all_of(supported.begin(), supported.end(),
-                                                     [](bool valid) { return valid; });
-                });
-        ASSERT_TRUE(supportedCall.isOk());
-
-        // launch prepare model
-        sp<PreparedModelCallback> preparedModelCallback = new PreparedModelCallback();
-        Return<ErrorStatus> prepareLaunchStatus =
-                device->prepareModel(model, preparedModelCallback);
-        ASSERT_TRUE(prepareLaunchStatus.isOk());
-        ASSERT_EQ(ErrorStatus::NONE, static_cast<ErrorStatus>(prepareLaunchStatus));
-
-        // retrieve prepared model
-        preparedModelCallback->wait();
-        ErrorStatus prepareReturnStatus = preparedModelCallback->getStatus();
-        sp<IPreparedModel> preparedModel = preparedModelCallback->getPreparedModel();
-
-        // early termination if vendor service cannot fully prepare model
-        if (!fullySupportsModel && prepareReturnStatus != ErrorStatus::NONE) {
-            ASSERT_EQ(nullptr, preparedModel.get());
-            LOG(INFO) << "NN VTS: Early termination of test because vendor service cannot "
-                         "prepare model that it does not support.";
-            std::cout << "[          ]   Early termination of test because vendor service cannot "
-                         "prepare model that it does not support."
-                      << std::endl;
-            GTEST_SKIP();
-        }
-        EXPECT_EQ(ErrorStatus::NONE, prepareReturnStatus);
-        ASSERT_NE(nullptr, preparedModel.get());
-
-        EvaluatePreparedModel(preparedModel, testModel);
-    }
-};
+class GeneratedTest : public GeneratedTestBase {};
 
 TEST_P(GeneratedTest, Test) {
-    Execute(*mTestModel);
+    Execute(kDevice, kTestModel);
 }
 
 INSTANTIATE_GENERATED_TEST(GeneratedTest,
diff --git a/neuralnetworks/1.0/vts/functional/GeneratedTestHarness.h b/neuralnetworks/1.0/vts/functional/GeneratedTestHarness.h
index a42f271..10e46b7 100644
--- a/neuralnetworks/1.0/vts/functional/GeneratedTestHarness.h
+++ b/neuralnetworks/1.0/vts/functional/GeneratedTestHarness.h
@@ -25,32 +25,20 @@
 
 class GeneratedTestBase
     : public NeuralnetworksHidlTest,
-      public ::testing::WithParamInterface<test_helper::TestModelManager::TestParam> {
+      public testing::WithParamInterface<test_helper::TestModelManager::TestParam> {
   protected:
-    void SetUp() override {
-        NeuralnetworksHidlTest::SetUp();
-        ASSERT_NE(mTestModel, nullptr);
-    }
-
-    const test_helper::TestModel* mTestModel = GetParam().second;
+    const test_helper::TestModel& kTestModel = *GetParam().second;
 };
 
-#define INSTANTIATE_GENERATED_TEST(TestSuite, filter)                                          \
-    INSTANTIATE_TEST_SUITE_P(                                                                  \
-            TestGenerated, TestSuite,                                                          \
-            ::testing::ValuesIn(::test_helper::TestModelManager::get().getTestModels(filter)), \
+#define INSTANTIATE_GENERATED_TEST(TestSuite, filter)                                        \
+    INSTANTIATE_TEST_SUITE_P(                                                                \
+            TestGenerated, TestSuite,                                                        \
+            testing::ValuesIn(::test_helper::TestModelManager::get().getTestModels(filter)), \
             [](const auto& info) { return info.param.first; })
 
 // Tag for the validation tests, instantiated in VtsHalNeuralnetworks.cpp.
 // TODO: Clean up the hierarchy for ValidationTest.
-class ValidationTest : public GeneratedTestBase {
-  protected:
-    void validateEverything(const Model& model, const Request& request);
-
-  private:
-    void validateModel(const Model& model);
-    void validateRequest(const sp<IPreparedModel>& preparedModel, const Request& request);
-};
+class ValidationTest : public GeneratedTestBase {};
 
 Model createModel(const ::test_helper::TestModel& testModel);
 
diff --git a/neuralnetworks/1.0/vts/functional/Utils.cpp b/neuralnetworks/1.0/vts/functional/Utils.cpp
index 5de99fd..307003c 100644
--- a/neuralnetworks/1.0/vts/functional/Utils.cpp
+++ b/neuralnetworks/1.0/vts/functional/Utils.cpp
@@ -26,6 +26,7 @@
 #include <hidlmemory/mapping.h>
 
 #include <algorithm>
+#include <iostream>
 #include <vector>
 
 namespace android::hardware::neuralnetworks {
@@ -117,3 +118,15 @@
 }
 
 }  // namespace android::hardware::neuralnetworks
+
+namespace android::hardware::neuralnetworks::V1_0 {
+
+::std::ostream& operator<<(::std::ostream& os, ErrorStatus errorStatus) {
+    return os << toString(errorStatus);
+}
+
+::std::ostream& operator<<(::std::ostream& os, DeviceStatus deviceStatus) {
+    return os << toString(deviceStatus);
+}
+
+}  // namespace android::hardware::neuralnetworks::V1_0
diff --git a/neuralnetworks/1.0/vts/functional/ValidateModel.cpp b/neuralnetworks/1.0/vts/functional/ValidateModel.cpp
index 9854395..cc15263 100644
--- a/neuralnetworks/1.0/vts/functional/ValidateModel.cpp
+++ b/neuralnetworks/1.0/vts/functional/ValidateModel.cpp
@@ -27,7 +27,7 @@
 ///////////////////////// UTILITY FUNCTIONS /////////////////////////
 
 static void validateGetSupportedOperations(const sp<IDevice>& device, const std::string& message,
-                                           const V1_0::Model& model) {
+                                           const Model& model) {
     SCOPED_TRACE(message + " [getSupportedOperations]");
 
     Return<void> ret =
@@ -38,7 +38,7 @@
 }
 
 static void validatePrepareModel(const sp<IDevice>& device, const std::string& message,
-                                 const V1_0::Model& model) {
+                                 const Model& model) {
     SCOPED_TRACE(message + " [prepareModel]");
 
     sp<PreparedModelCallback> preparedModelCallback = new PreparedModelCallback();
@@ -57,7 +57,7 @@
 // mutation to it to invalidate the model, then pass it to interface calls that
 // use the model. Note that the model here is passed by value, and any mutation
 // to the model does not leave this function.
-static void validate(const sp<IDevice>& device, const std::string& message, V1_0::Model model,
+static void validate(const sp<IDevice>& device, const std::string& message, Model model,
                      const std::function<void(Model*)>& mutation) {
     mutation(&model);
     validateGetSupportedOperations(device, message, model);
@@ -113,7 +113,7 @@
         static_cast<int32_t>(OperandType::TENSOR_OEM_BYTE) + 1,      // upper bound OEM
 };
 
-static void mutateOperandTypeTest(const sp<IDevice>& device, const V1_0::Model& model) {
+static void mutateOperandTypeTest(const sp<IDevice>& device, const Model& model) {
     for (size_t operand = 0; operand < model.operands.size(); ++operand) {
         for (int32_t invalidOperandType : invalidOperandTypes) {
             const std::string message = "mutateOperandTypeTest: operand " +
@@ -143,7 +143,7 @@
     }
 }
 
-static void mutateOperandRankTest(const sp<IDevice>& device, const V1_0::Model& model) {
+static void mutateOperandRankTest(const sp<IDevice>& device, const Model& model) {
     for (size_t operand = 0; operand < model.operands.size(); ++operand) {
         const uint32_t invalidRank = getInvalidRank(model.operands[operand].type);
         const std::string message = "mutateOperandRankTest: operand " + std::to_string(operand) +
@@ -172,7 +172,7 @@
     }
 }
 
-static void mutateOperandScaleTest(const sp<IDevice>& device, const V1_0::Model& model) {
+static void mutateOperandScaleTest(const sp<IDevice>& device, const Model& model) {
     for (size_t operand = 0; operand < model.operands.size(); ++operand) {
         const float invalidScale = getInvalidScale(model.operands[operand].type);
         const std::string message = "mutateOperandScaleTest: operand " + std::to_string(operand) +
@@ -200,7 +200,7 @@
     }
 }
 
-static void mutateOperandZeroPointTest(const sp<IDevice>& device, const V1_0::Model& model) {
+static void mutateOperandZeroPointTest(const sp<IDevice>& device, const Model& model) {
     for (size_t operand = 0; operand < model.operands.size(); ++operand) {
         const std::vector<int32_t> invalidZeroPoints =
                 getInvalidZeroPoints(model.operands[operand].type);
@@ -257,7 +257,7 @@
     *operand = newOperand;
 }
 
-static bool mutateOperationOperandTypeSkip(size_t operand, const V1_0::Model& model) {
+static bool mutateOperationOperandTypeSkip(size_t operand, const Model& model) {
     // LSH_PROJECTION's second argument is allowed to have any type. This is the
     // only operation that currently has a type that can be anything independent
     // from any other type. Changing the operand type to any other type will
@@ -271,7 +271,7 @@
     return false;
 }
 
-static void mutateOperationOperandTypeTest(const sp<IDevice>& device, const V1_0::Model& model) {
+static void mutateOperationOperandTypeTest(const sp<IDevice>& device, const Model& model) {
     for (size_t operand = 0; operand < model.operands.size(); ++operand) {
         if (mutateOperationOperandTypeSkip(operand, model)) {
             continue;
@@ -302,7 +302,7 @@
         static_cast<int32_t>(OperationType::OEM_OPERATION) + 1,  // upper bound OEM
 };
 
-static void mutateOperationTypeTest(const sp<IDevice>& device, const V1_0::Model& model) {
+static void mutateOperationTypeTest(const sp<IDevice>& device, const Model& model) {
     for (size_t operation = 0; operation < model.operations.size(); ++operation) {
         for (int32_t invalidOperationType : invalidOperationTypes) {
             const std::string message = "mutateOperationTypeTest: operation " +
@@ -318,8 +318,7 @@
 
 ///////////////////////// VALIDATE MODEL OPERATION INPUT OPERAND INDEX /////////////////////////
 
-static void mutateOperationInputOperandIndexTest(const sp<IDevice>& device,
-                                                 const V1_0::Model& model) {
+static void mutateOperationInputOperandIndexTest(const sp<IDevice>& device, const Model& model) {
     for (size_t operation = 0; operation < model.operations.size(); ++operation) {
         const uint32_t invalidOperand = model.operands.size();
         for (size_t input = 0; input < model.operations[operation].inputs.size(); ++input) {
@@ -335,8 +334,7 @@
 
 ///////////////////////// VALIDATE MODEL OPERATION OUTPUT OPERAND INDEX /////////////////////////
 
-static void mutateOperationOutputOperandIndexTest(const sp<IDevice>& device,
-                                                  const V1_0::Model& model) {
+static void mutateOperationOutputOperandIndexTest(const sp<IDevice>& device, const Model& model) {
     for (size_t operation = 0; operation < model.operations.size(); ++operation) {
         const uint32_t invalidOperand = model.operands.size();
         for (size_t output = 0; output < model.operations[operation].outputs.size(); ++output) {
@@ -374,7 +372,7 @@
     removeValueAndDecrementGreaterValues(&model->outputIndexes, index);
 }
 
-static void removeOperandTest(const sp<IDevice>& device, const V1_0::Model& model) {
+static void removeOperandTest(const sp<IDevice>& device, const Model& model) {
     for (size_t operand = 0; operand < model.operands.size(); ++operand) {
         const std::string message = "removeOperandTest: operand " + std::to_string(operand);
         validate(device, message, model,
@@ -391,7 +389,7 @@
     hidl_vec_removeAt(&model->operations, index);
 }
 
-static void removeOperationTest(const sp<IDevice>& device, const V1_0::Model& model) {
+static void removeOperationTest(const sp<IDevice>& device, const Model& model) {
     for (size_t operation = 0; operation < model.operations.size(); ++operation) {
         const std::string message = "removeOperationTest: operation " + std::to_string(operation);
         validate(device, message, model,
@@ -401,14 +399,14 @@
 
 ///////////////////////// REMOVE OPERATION INPUT /////////////////////////
 
-static void removeOperationInputTest(const sp<IDevice>& device, const V1_0::Model& model) {
+static void removeOperationInputTest(const sp<IDevice>& device, const Model& model) {
     for (size_t operation = 0; operation < model.operations.size(); ++operation) {
         for (size_t input = 0; input < model.operations[operation].inputs.size(); ++input) {
-            const V1_0::Operation& op = model.operations[operation];
+            const Operation& op = model.operations[operation];
             // CONCATENATION has at least 2 inputs, with the last element being
             // INT32. Skip this test if removing one of CONCATENATION's
             // inputs still produces a valid model.
-            if (op.type == V1_0::OperationType::CONCATENATION && op.inputs.size() > 2 &&
+            if (op.type == OperationType::CONCATENATION && op.inputs.size() > 2 &&
                 input != op.inputs.size() - 1) {
                 continue;
             }
@@ -426,7 +424,7 @@
 
 ///////////////////////// REMOVE OPERATION OUTPUT /////////////////////////
 
-static void removeOperationOutputTest(const sp<IDevice>& device, const V1_0::Model& model) {
+static void removeOperationOutputTest(const sp<IDevice>& device, const Model& model) {
     for (size_t operation = 0; operation < model.operations.size(); ++operation) {
         for (size_t output = 0; output < model.operations[operation].outputs.size(); ++output) {
             const std::string message = "removeOperationOutputTest: operation " +
@@ -447,7 +445,7 @@
 
 ///////////////////////// ADD OPERATION INPUT /////////////////////////
 
-static void addOperationInputTest(const sp<IDevice>& device, const V1_0::Model& model) {
+static void addOperationInputTest(const sp<IDevice>& device, const Model& model) {
     for (size_t operation = 0; operation < model.operations.size(); ++operation) {
         const std::string message = "addOperationInputTest: operation " + std::to_string(operation);
         validate(device, message, model, [operation](Model* model) {
@@ -460,7 +458,7 @@
 
 ///////////////////////// ADD OPERATION OUTPUT /////////////////////////
 
-static void addOperationOutputTest(const sp<IDevice>& device, const V1_0::Model& model) {
+static void addOperationOutputTest(const sp<IDevice>& device, const Model& model) {
     for (size_t operation = 0; operation < model.operations.size(); ++operation) {
         const std::string message =
                 "addOperationOutputTest: operation " + std::to_string(operation);
@@ -474,7 +472,7 @@
 
 ////////////////////////// ENTRY POINT //////////////////////////////
 
-void ValidationTest::validateModel(const V1_0::Model& model) {
+void validateModel(const sp<IDevice>& device, const Model& model) {
     mutateOperandTypeTest(device, model);
     mutateOperandRankTest(device, model);
     mutateOperandScaleTest(device, model);
diff --git a/neuralnetworks/1.0/vts/functional/ValidateRequest.cpp b/neuralnetworks/1.0/vts/functional/ValidateRequest.cpp
index d8f3e65..05eefd1 100644
--- a/neuralnetworks/1.0/vts/functional/ValidateRequest.cpp
+++ b/neuralnetworks/1.0/vts/functional/ValidateRequest.cpp
@@ -87,8 +87,7 @@
 
 ///////////////////////////// ENTRY POINT //////////////////////////////////
 
-void ValidationTest::validateRequest(const sp<IPreparedModel>& preparedModel,
-                                     const Request& request) {
+void validateRequest(const sp<IPreparedModel>& preparedModel, const Request& request) {
     removeInputTest(preparedModel, request);
     removeOutputTest(preparedModel, request);
 }
diff --git a/neuralnetworks/1.0/vts/functional/VtsHalNeuralnetworks.cpp b/neuralnetworks/1.0/vts/functional/VtsHalNeuralnetworks.cpp
index 9ee4e37..20b4565 100644
--- a/neuralnetworks/1.0/vts/functional/VtsHalNeuralnetworks.cpp
+++ b/neuralnetworks/1.0/vts/functional/VtsHalNeuralnetworks.cpp
@@ -28,30 +28,32 @@
 
 using implementation::PreparedModelCallback;
 
-static void createPreparedModel(const sp<IDevice>& device, const Model& model,
-                                sp<IPreparedModel>* preparedModel) {
+void createPreparedModel(const sp<IDevice>& device, const Model& model,
+                         sp<IPreparedModel>* preparedModel) {
     ASSERT_NE(nullptr, preparedModel);
+    *preparedModel = nullptr;
 
     // see if service can handle model
     bool fullySupportsModel = false;
-    Return<void> supportedOpsLaunchStatus = device->getSupportedOperations(
+    const Return<void> supportedCall = device->getSupportedOperations(
             model, [&fullySupportsModel](ErrorStatus status, const hidl_vec<bool>& supported) {
                 ASSERT_EQ(ErrorStatus::NONE, status);
                 ASSERT_NE(0ul, supported.size());
                 fullySupportsModel = std::all_of(supported.begin(), supported.end(),
                                                  [](bool valid) { return valid; });
             });
-    ASSERT_TRUE(supportedOpsLaunchStatus.isOk());
+    ASSERT_TRUE(supportedCall.isOk());
 
     // launch prepare model
-    sp<PreparedModelCallback> preparedModelCallback = new PreparedModelCallback();
-    Return<ErrorStatus> prepareLaunchStatus = device->prepareModel(model, preparedModelCallback);
+    const sp<PreparedModelCallback> preparedModelCallback = new PreparedModelCallback();
+    const Return<ErrorStatus> prepareLaunchStatus =
+            device->prepareModel(model, preparedModelCallback);
     ASSERT_TRUE(prepareLaunchStatus.isOk());
     ASSERT_EQ(ErrorStatus::NONE, static_cast<ErrorStatus>(prepareLaunchStatus));
 
     // retrieve prepared model
     preparedModelCallback->wait();
-    ErrorStatus prepareReturnStatus = preparedModelCallback->getStatus();
+    const ErrorStatus prepareReturnStatus = preparedModelCallback->getStatus();
     *preparedModel = preparedModelCallback->getPreparedModel();
 
     // The getSupportedOperations call returns a list of operations that are
@@ -63,12 +65,12 @@
     // can continue.
     if (!fullySupportsModel && prepareReturnStatus != ErrorStatus::NONE) {
         ASSERT_EQ(nullptr, preparedModel->get());
-        LOG(INFO) << "NN VTS: Unable to test Request validation because vendor service cannot "
-                     "prepare model that it does not support.";
-        std::cout << "[          ]   Unable to test Request validation because vendor service "
-                     "cannot prepare model that it does not support."
+        LOG(INFO) << "NN VTS: Early termination of test because vendor service cannot prepare "
+                     "model that it does not support.";
+        std::cout << "[          ]   Early termination of test because vendor service cannot "
+                     "prepare model that it does not support."
                   << std::endl;
-        return;
+        GTEST_SKIP();
     }
     ASSERT_EQ(ErrorStatus::NONE, prepareReturnStatus);
     ASSERT_NE(nullptr, preparedModel->get());
@@ -77,7 +79,7 @@
 // A class for test environment setup
 NeuralnetworksHidlEnvironment* NeuralnetworksHidlEnvironment::getInstance() {
     // This has to return a "new" object because it is freed inside
-    // ::testing::AddGlobalTestEnvironment when the gtest is being torn down
+    // testing::AddGlobalTestEnvironment when the gtest is being torn down
     static NeuralnetworksHidlEnvironment* instance = new NeuralnetworksHidlEnvironment();
     return instance;
 }
@@ -88,28 +90,29 @@
 
 // The main test class for NEURALNETWORK HIDL HAL.
 void NeuralnetworksHidlTest::SetUp() {
-    ::testing::VtsHalHidlTargetTestBase::SetUp();
+    testing::VtsHalHidlTargetTestBase::SetUp();
 
 #ifdef PRESUBMIT_NOT_VTS
     const std::string name =
             NeuralnetworksHidlEnvironment::getInstance()->getServiceName<IDevice>();
     const std::string sampleDriver = "sample-";
-    if (device == nullptr && name.substr(0, sampleDriver.size()) == sampleDriver) {
+    if (kDevice == nullptr && name.substr(0, sampleDriver.size()) == sampleDriver) {
         GTEST_SKIP();
     }
 #endif  // PRESUBMIT_NOT_VTS
 
-    ASSERT_NE(nullptr, device.get());
+    ASSERT_NE(nullptr, kDevice.get());
 }
 
-void NeuralnetworksHidlTest::TearDown() {
-    ::testing::VtsHalHidlTargetTestBase::TearDown();
-}
+// Forward declaration from ValidateModel.cpp
+void validateModel(const sp<IDevice>& device, const Model& model);
+// Forward declaration from ValidateRequest.cpp
+void validateRequest(const sp<IPreparedModel>& preparedModel, const Request& request);
 
-void ValidationTest::validateEverything(const Model& model, const Request& request) {
-    validateModel(model);
+void validateEverything(const sp<IDevice>& device, const Model& model, const Request& request) {
+    validateModel(device, model);
 
-    // create IPreparedModel
+    // Create IPreparedModel.
     sp<IPreparedModel> preparedModel;
     createPreparedModel(device, model, &preparedModel);
     if (preparedModel == nullptr) return;
@@ -118,33 +121,21 @@
 }
 
 TEST_P(ValidationTest, Test) {
-    const Model model = createModel(*mTestModel);
-    const Request request = createRequest(*mTestModel);
-    ASSERT_FALSE(mTestModel->expectFailure);
-    validateEverything(model, request);
+    const Model model = createModel(kTestModel);
+    const Request request = createRequest(kTestModel);
+    ASSERT_FALSE(kTestModel.expectFailure);
+    validateEverything(kDevice, model, request);
 }
 
 INSTANTIATE_GENERATED_TEST(ValidationTest, [](const test_helper::TestModel&) { return true; });
 
 }  // namespace android::hardware::neuralnetworks::V1_0::vts::functional
 
-namespace android::hardware::neuralnetworks::V1_0 {
-
-::std::ostream& operator<<(::std::ostream& os, ErrorStatus errorStatus) {
-    return os << toString(errorStatus);
-}
-
-::std::ostream& operator<<(::std::ostream& os, DeviceStatus deviceStatus) {
-    return os << toString(deviceStatus);
-}
-
-}  // namespace android::hardware::neuralnetworks::V1_0
-
 using android::hardware::neuralnetworks::V1_0::vts::functional::NeuralnetworksHidlEnvironment;
 
 int main(int argc, char** argv) {
-    ::testing::AddGlobalTestEnvironment(NeuralnetworksHidlEnvironment::getInstance());
-    ::testing::InitGoogleTest(&argc, argv);
+    testing::AddGlobalTestEnvironment(NeuralnetworksHidlEnvironment::getInstance());
+    testing::InitGoogleTest(&argc, argv);
     NeuralnetworksHidlEnvironment::getInstance()->init(&argc, argv);
 
     int status = RUN_ALL_TESTS();
diff --git a/neuralnetworks/1.0/vts/functional/VtsHalNeuralnetworks.h b/neuralnetworks/1.0/vts/functional/VtsHalNeuralnetworks.h
index fa9ad3b..48dc237 100644
--- a/neuralnetworks/1.0/vts/functional/VtsHalNeuralnetworks.h
+++ b/neuralnetworks/1.0/vts/functional/VtsHalNeuralnetworks.h
@@ -25,15 +25,11 @@
 
 #include <android-base/macros.h>
 #include <gtest/gtest.h>
-#include <iostream>
-#include <vector>
-
-#include "TestHarness.h"
 
 namespace android::hardware::neuralnetworks::V1_0::vts::functional {
 
 // A class for test environment setup
-class NeuralnetworksHidlEnvironment : public ::testing::VtsHalHidlTargetTestEnvBase {
+class NeuralnetworksHidlEnvironment : public testing::VtsHalHidlTargetTestEnvBase {
     DISALLOW_COPY_AND_ASSIGN(NeuralnetworksHidlEnvironment);
     NeuralnetworksHidlEnvironment() = default;
 
@@ -43,27 +39,23 @@
 };
 
 // The main test class for NEURALNETWORKS HIDL HAL.
-class NeuralnetworksHidlTest : public ::testing::VtsHalHidlTargetTestBase {
+class NeuralnetworksHidlTest : public testing::VtsHalHidlTargetTestBase {
     DISALLOW_COPY_AND_ASSIGN(NeuralnetworksHidlTest);
 
   public:
     NeuralnetworksHidlTest() = default;
     void SetUp() override;
-    void TearDown() override;
 
   protected:
-    const sp<IDevice> device = ::testing::VtsHalHidlTargetTestBase::getService<IDevice>(
+    const sp<IDevice> kDevice = testing::VtsHalHidlTargetTestBase::getService<IDevice>(
             NeuralnetworksHidlEnvironment::getInstance());
 };
 
+// Create an IPreparedModel object. If the model cannot be prepared,
+// "preparedModel" will be nullptr instead.
+void createPreparedModel(const sp<IDevice>& device, const Model& model,
+                         sp<IPreparedModel>* preparedModel);
+
 }  // namespace android::hardware::neuralnetworks::V1_0::vts::functional
 
-namespace android::hardware::neuralnetworks::V1_0 {
-
-// pretty-print values for error messages
-::std::ostream& operator<<(::std::ostream& os, ErrorStatus errorStatus);
-::std::ostream& operator<<(::std::ostream& os, DeviceStatus deviceStatus);
-
-}  // namespace android::hardware::neuralnetworks::V1_0
-
 #endif  // ANDROID_HARDWARE_NEURALNETWORKS_V1_0_VTS_HAL_NEURALNETWORKS_H
diff --git a/neuralnetworks/1.0/vts/functional/include/1.0/Utils.h b/neuralnetworks/1.0/vts/functional/include/1.0/Utils.h
index 274cb58..1ce751c 100644
--- a/neuralnetworks/1.0/vts/functional/include/1.0/Utils.h
+++ b/neuralnetworks/1.0/vts/functional/include/1.0/Utils.h
@@ -20,6 +20,7 @@
 #include <android-base/logging.h>
 #include <android/hardware/neuralnetworks/1.0/types.h>
 #include <algorithm>
+#include <iosfwd>
 #include <vector>
 #include "TestHarness.h"
 
@@ -52,4 +53,12 @@
 
 }  // namespace android::hardware::neuralnetworks
 
+namespace android::hardware::neuralnetworks::V1_0 {
+
+// pretty-print values for error messages
+::std::ostream& operator<<(::std::ostream& os, ErrorStatus errorStatus);
+::std::ostream& operator<<(::std::ostream& os, DeviceStatus deviceStatus);
+
+}  // namespace android::hardware::neuralnetworks::V1_0
+
 #endif  // ANDROID_HARDWARE_NEURALNETWORKS_V1_0_UTILS_H