Add WiFi precondition check to 'net' CTS module

bug:23939594
Change-Id: I9e625e635fc6942c9eaa95915888f0fe7284a9ea
diff --git a/tests/cts/net/AndroidTest.xml b/tests/cts/net/AndroidTest.xml
index ee0d636..d52214e 100644
--- a/tests/cts/net/AndroidTest.xml
+++ b/tests/cts/net/AndroidTest.xml
@@ -19,4 +19,11 @@
         <option name="package" value="android.net.cts" />
         <option name="runner" value="android.support.test.runner.AndroidJUnitRunner" />
     </test>
+
+    <target_preparer class="com.android.compatibility.common.tradefed.targetprep.ApkPreconditionCheck">
+        <option name="apk-name" value="CtsNetPreconditions.apk"/>
+        <option name="package-name" value="android.net.preconditions"/>
+        <option name="runner" value="android.support.test.runner.AndroidJUnitRunner"/>
+    </target_preparer>
+
 </configuration>