diff --git a/neuralnetworks/1.0/vts/functional/VtsHalNeuralnetworks.cpp b/neuralnetworks/1.0/vts/functional/VtsHalNeuralnetworks.cpp
index 1ff3b66808..9ebc0aac47 100644
--- a/neuralnetworks/1.0/vts/functional/VtsHalNeuralnetworks.cpp
+++ b/neuralnetworks/1.0/vts/functional/VtsHalNeuralnetworks.cpp
@@ -60,6 +60,12 @@ void NeuralnetworksHidlTest::TearDown() {
 
 }  // namespace functional
 }  // namespace vts
+}  // namespace V1_0
+}  // namespace neuralnetworks
+}  // namespace hardware
+}  // namespace android
+
+namespace android::hardware::neuralnetworks::V1_0 {
 
 ::std::ostream& operator<<(::std::ostream& os, ErrorStatus errorStatus) {
     return os << toString(errorStatus);
@@ -69,10 +75,7 @@ void NeuralnetworksHidlTest::TearDown() {
     return os << toString(deviceStatus);
 }
 
-}  // namespace V1_0
-}  // namespace neuralnetworks
-}  // namespace hardware
-}  // namespace android
+}  // namespace android::hardware::neuralnetworks::V1_0
 
 using android::hardware::neuralnetworks::V1_0::vts::functional::NeuralnetworksHidlEnvironment;
 
diff --git a/neuralnetworks/1.0/vts/functional/VtsHalNeuralnetworks.h b/neuralnetworks/1.0/vts/functional/VtsHalNeuralnetworks.h
index e79129b09f..d4c114d3a2 100644
--- a/neuralnetworks/1.0/vts/functional/VtsHalNeuralnetworks.h
+++ b/neuralnetworks/1.0/vts/functional/VtsHalNeuralnetworks.h
@@ -72,14 +72,17 @@ class GeneratedTest : public NeuralnetworksHidlTest {};
 
 }  // namespace functional
 }  // namespace vts
-
-// pretty-print values for error messages
-::std::ostream& operator<<(::std::ostream& os, ErrorStatus errorStatus);
-::std::ostream& operator<<(::std::ostream& os, DeviceStatus deviceStatus);
-
 }  // namespace V1_0
 }  // namespace neuralnetworks
 }  // namespace hardware
 }  // namespace android
 
+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  // VTS_HAL_NEURALNETWORKS_V1_0_TARGET_TESTS_H
diff --git a/neuralnetworks/1.1/vts/functional/VtsHalNeuralnetworks.cpp b/neuralnetworks/1.1/vts/functional/VtsHalNeuralnetworks.cpp
index 62381e6796..4165953df2 100644
--- a/neuralnetworks/1.1/vts/functional/VtsHalNeuralnetworks.cpp
+++ b/neuralnetworks/1.1/vts/functional/VtsHalNeuralnetworks.cpp
@@ -60,6 +60,12 @@ void NeuralnetworksHidlTest::TearDown() {
 
 }  // namespace functional
 }  // namespace vts
+}  // namespace V1_1
+}  // namespace neuralnetworks
+}  // namespace hardware
+}  // namespace android
+
+namespace android::hardware::neuralnetworks::V1_0 {
 
 ::std::ostream& operator<<(::std::ostream& os, ErrorStatus errorStatus) {
     return os << toString(errorStatus);
@@ -69,10 +75,7 @@ void NeuralnetworksHidlTest::TearDown() {
     return os << toString(deviceStatus);
 }
 
-}  // namespace V1_1
-}  // namespace neuralnetworks
-}  // namespace hardware
-}  // namespace android
+}  // namespace android::hardware::neuralnetworks::V1_0
 
 using android::hardware::neuralnetworks::V1_1::vts::functional::NeuralnetworksHidlEnvironment;
 
diff --git a/neuralnetworks/1.1/vts/functional/VtsHalNeuralnetworks.h b/neuralnetworks/1.1/vts/functional/VtsHalNeuralnetworks.h
index 970e8b5537..1c8c0e18cb 100644
--- a/neuralnetworks/1.1/vts/functional/VtsHalNeuralnetworks.h
+++ b/neuralnetworks/1.1/vts/functional/VtsHalNeuralnetworks.h
@@ -81,14 +81,17 @@ class GeneratedTest : public NeuralnetworksHidlTest {};
 
 }  // namespace functional
 }  // namespace vts
-
-// pretty-print values for error messages
-::std::ostream& operator<<(::std::ostream& os, ErrorStatus errorStatus);
-::std::ostream& operator<<(::std::ostream& os, DeviceStatus deviceStatus);
-
 }  // namespace V1_1
 }  // namespace neuralnetworks
 }  // namespace hardware
 }  // namespace android
 
+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  // VTS_HAL_NEURALNETWORKS_V1_1_H
diff --git a/neuralnetworks/1.2/vts/functional/VtsHalNeuralnetworks.cpp b/neuralnetworks/1.2/vts/functional/VtsHalNeuralnetworks.cpp
index 4eced82352..34c73ef05d 100644
--- a/neuralnetworks/1.2/vts/functional/VtsHalNeuralnetworks.cpp
+++ b/neuralnetworks/1.2/vts/functional/VtsHalNeuralnetworks.cpp
@@ -66,6 +66,12 @@ sp<IPreparedModel> getPreparedModel_1_2(
 
 }  // namespace functional
 }  // namespace vts
+}  // namespace V1_2
+}  // namespace neuralnetworks
+}  // namespace hardware
+}  // namespace android
+
+namespace android::hardware::neuralnetworks::V1_0 {
 
 ::std::ostream& operator<<(::std::ostream& os, ErrorStatus errorStatus) {
     return os << toString(errorStatus);
@@ -75,10 +81,7 @@ sp<IPreparedModel> getPreparedModel_1_2(
     return os << toString(deviceStatus);
 }
 
-}  // namespace V1_2
-}  // namespace neuralnetworks
-}  // namespace hardware
-}  // namespace android
+}  // namespace android::hardware::neuralnetworks::V1_0
 
 using android::hardware::neuralnetworks::V1_2::vts::functional::NeuralnetworksHidlEnvironment;
 
diff --git a/neuralnetworks/1.2/vts/functional/VtsHalNeuralnetworks.h b/neuralnetworks/1.2/vts/functional/VtsHalNeuralnetworks.h
index c0c21bddf0..404eec06db 100644
--- a/neuralnetworks/1.2/vts/functional/VtsHalNeuralnetworks.h
+++ b/neuralnetworks/1.2/vts/functional/VtsHalNeuralnetworks.h
@@ -88,14 +88,17 @@ sp<IPreparedModel> getPreparedModel_1_2(
 
 }  // namespace functional
 }  // namespace vts
-
-// pretty-print values for error messages
-::std::ostream& operator<<(::std::ostream& os, ErrorStatus errorStatus);
-::std::ostream& operator<<(::std::ostream& os, DeviceStatus deviceStatus);
-
 }  // namespace V1_2
 }  // namespace neuralnetworks
 }  // namespace hardware
 }  // namespace android
 
+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  // VTS_HAL_NEURALNETWORKS_V1_2_H