diff --git a/framework/api/module-lib-current.txt b/framework/api/module-lib-current.txt
index d2ed73e..6df57c1 100644
--- a/framework/api/module-lib-current.txt
+++ b/framework/api/module-lib-current.txt
@@ -51,6 +51,14 @@
     field public static final String TEST_TAP_PREFIX = "testtap";
   }
 
+  public final class TestNetworkSpecifier extends android.net.NetworkSpecifier implements android.os.Parcelable {
+    ctor public TestNetworkSpecifier(@NonNull String);
+    method public int describeContents();
+    method @Nullable public String getInterfaceName();
+    method public void writeToParcel(@NonNull android.os.Parcel, int);
+    field @NonNull public static final android.os.Parcelable.Creator<android.net.TestNetworkSpecifier> CREATOR;
+  }
+
   public final class VpnTransportInfo implements android.os.Parcelable android.net.TransportInfo {
     ctor public VpnTransportInfo(int);
     method public int describeContents();
diff --git a/framework/src/android/net/NetworkRequest.java b/framework/src/android/net/NetworkRequest.java
index b4a651c..17a8ee1 100644
--- a/framework/src/android/net/NetworkRequest.java
+++ b/framework/src/android/net/NetworkRequest.java
@@ -31,6 +31,7 @@
 import static android.net.NetworkCapabilities.NET_CAPABILITY_TEMPORARILY_NOT_METERED;
 import static android.net.NetworkCapabilities.NET_CAPABILITY_TRUSTED;
 import static android.net.NetworkCapabilities.NET_CAPABILITY_VALIDATED;
+import static android.net.NetworkCapabilities.TRANSPORT_TEST;
 
 import android.annotation.NonNull;
 import android.annotation.Nullable;
@@ -382,11 +383,17 @@
                 return setNetworkSpecifier(new TelephonyNetworkSpecifier.Builder()
                         .setSubscriptionId(subId).build());
             } catch (NumberFormatException nfe) {
-                // A StringNetworkSpecifier does not accept null or empty ("") strings. When network
-                // specifiers were strings a null string and an empty string were considered
-                // equivalent. Hence no meaning is attached to a null or empty ("") string.
-                return setNetworkSpecifier(TextUtils.isEmpty(networkSpecifier) ? null
-                        : new StringNetworkSpecifier(networkSpecifier));
+                // An EthernetNetworkSpecifier or TestNetworkSpecifier does not accept null or empty
+                // ("") strings. When network specifiers were strings a null string and an empty
+                // string were considered equivalent. Hence no meaning is attached to a null or
+                // empty ("") string.
+                if (TextUtils.isEmpty(networkSpecifier)) {
+                    return setNetworkSpecifier((NetworkSpecifier) null);
+                } else if (mNetworkCapabilities.hasTransport(TRANSPORT_TEST)) {
+                    return setNetworkSpecifier(new TestNetworkSpecifier(networkSpecifier));
+                } else {
+                    return setNetworkSpecifier(new EthernetNetworkSpecifier(networkSpecifier));
+                }
             }
         }
 
diff --git a/framework/src/android/net/TestNetworkSpecifier.java b/framework/src/android/net/TestNetworkSpecifier.java
new file mode 100644
index 0000000..b7470a5
--- /dev/null
+++ b/framework/src/android/net/TestNetworkSpecifier.java
@@ -0,0 +1,97 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * 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.
+ */
+
+package android.net;
+
+import android.annotation.NonNull;
+import android.annotation.Nullable;
+import android.annotation.SystemApi;
+import android.os.Parcel;
+import android.os.Parcelable;
+import android.text.TextUtils;
+
+import com.android.internal.util.Preconditions;
+
+import java.util.Objects;
+
+/**
+ * A {@link NetworkSpecifier} used to identify test interfaces.
+ *
+ * @see TestNetworkManager
+ * @hide
+ */
+@SystemApi(client = SystemApi.Client.MODULE_LIBRARIES)
+public final class TestNetworkSpecifier extends NetworkSpecifier implements Parcelable {
+
+    /**
+     * Name of the network interface.
+     */
+    @NonNull
+    private final String mInterfaceName;
+
+    public TestNetworkSpecifier(@NonNull String interfaceName) {
+        Preconditions.checkStringNotEmpty(interfaceName);
+        mInterfaceName = interfaceName;
+    }
+
+    // This may be null in the future to support specifiers based on data other than the interface
+    // name.
+    @Nullable
+    public String getInterfaceName() {
+        return mInterfaceName;
+    }
+
+    @Override
+    public boolean canBeSatisfiedBy(@Nullable NetworkSpecifier other) {
+        return equals(other);
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (!(o instanceof TestNetworkSpecifier)) return false;
+        return TextUtils.equals(mInterfaceName, ((TestNetworkSpecifier) o).mInterfaceName);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hashCode(mInterfaceName);
+    }
+
+    @Override
+    public String toString() {
+        return "TestNetworkSpecifier (" + mInterfaceName + ")";
+    }
+
+    @Override
+    public int describeContents() {
+        return 0;
+    }
+
+    @Override
+    public void writeToParcel(@NonNull Parcel dest, int flags) {
+        dest.writeString(mInterfaceName);
+    }
+
+    public static final @NonNull Creator<TestNetworkSpecifier> CREATOR =
+            new Creator<TestNetworkSpecifier>() {
+        public TestNetworkSpecifier createFromParcel(Parcel in) {
+            return new TestNetworkSpecifier(in.readString());
+        }
+        public TestNetworkSpecifier[] newArray(int size) {
+            return new TestNetworkSpecifier[size];
+        }
+    };
+}