diff --git a/staticlibs/devicetests/com/android/testutils/ConcurrentInterpreter.kt b/staticlibs/devicetests/com/android/testutils/ConcurrentInterpreter.kt
new file mode 100644
index 0000000..98464eb
--- /dev/null
+++ b/staticlibs/devicetests/com/android/testutils/ConcurrentInterpreter.kt
@@ -0,0 +1,188 @@
+package com.android.testutils
+
+import android.os.SystemClock
+import java.util.concurrent.CyclicBarrier
+import kotlin.system.measureTimeMillis
+import kotlin.test.assertEquals
+import kotlin.test.assertFails
+import kotlin.test.assertNull
+import kotlin.test.assertTrue
+
+// The table contains pairs associating a regexp with the code to run. The statement is matched
+// against each matcher in sequence and when a match is found the associated code is run, passing
+// it the TrackRecord under test and the result of the regexp match.
+typealias InterpretMatcher<T> = Pair<Regex, (ConcurrentInterpreter<T>, T, MatchResult) -> Any?>
+
+// The default unit of time for interpreted tests
+val INTERPRET_TIME_UNIT = 40L // ms
+
+/**
+ * A small interpreter for testing parallel code. The interpreter will read a list of lines
+ * consisting of "|"-separated statements. Each column runs in a different concurrent thread
+ * and all threads wait for each other in between lines. Each statement is split on ";" then
+ * matched with regular expressions in the instructionTable constant, which contains the
+ * code associated with each statement. The interpreter supports an object being passed to
+ * the interpretTestSpec() method to be passed in each lambda (think about the object under
+ * test), and an optional transform function to be executed on the object at the start of
+ * every thread.
+ *
+ * The time unit is defined in milliseconds by the interpretTimeUnit member, which has a default
+ * value but can be passed to the constructor. Whitespace is ignored.
+ *
+ * The interpretation table has to be passed as an argument. It's a table associating a regexp
+ * with the code that should execute, as a function taking three arguments : the interpreter,
+ * the regexp match, and the object. See the individual tests for the DSL of that test.
+ * Implementors for new interpreting languages are encouraged to look at the defaultInterpretTable
+ * constant below for an example of how to write an interpreting table.
+ * Some expressions already exist by default and can be used by all interpreters. They include :
+ * sleep(x) : sleeps for x time units and returns Unit ; sleep alone means sleep(1)
+ * EXPR = VALUE : asserts that EXPR equals VALUE. EXPR is interpreted. VALUE can either be the
+ *   string "null" or an int. Returns Unit.
+ * EXPR time x..y : measures the time taken by EXPR and asserts it took at least x and at most
+ *   y time units.
+ * EXPR // any text : comments are ignored.
+ */
+open class ConcurrentInterpreter<T>(
+    localInterpretTable: List<InterpretMatcher<T>>,
+    val interpretTimeUnit: Long = INTERPRET_TIME_UNIT
+) {
+    private val interpretTable: List<InterpretMatcher<T>> =
+            localInterpretTable + getDefaultInstructions()
+
+    // Split the line into multiple statements separated by ";" and execute them. Return whatever
+    // the last statement returned.
+    fun interpretMultiple(instr: String, r: T): Any? {
+        return instr.split(";").map { interpret(it.trim(), r) }.last()
+    }
+
+    // Match the statement to a regex and interpret it.
+    fun interpret(instr: String, r: T): Any? {
+        val (matcher, code) =
+                interpretTable.find { instr matches it.first } ?: throw SyntaxException(instr)
+        val match = matcher.matchEntire(instr) ?: throw SyntaxException(instr)
+        return code(this, r, match)
+    }
+
+    // Spins as many threads as needed by the test spec and interpret each program concurrently,
+    // having all threads waiting on a CyclicBarrier after each line.
+    // |lineShift| says how many lines after the call the spec starts. This is used for error
+    // reporting. Unfortunately AFAICT there is no way to get the line of an argument rather
+    // than the line at which the expression starts.
+    fun interpretTestSpec(
+        spec: String,
+        initial: T,
+        lineShift: Int = 0,
+        threadTransform: (T) -> T = { it }
+    ) {
+        // For nice stack traces
+        val callSite = getCallingMethod()
+        val lines = spec.trim().trim('\n').split("\n").map { it.split("|") }
+        // |threads| contains arrays of strings that make up the statements of a thread : in other
+        // words, it's an array that contains a list of statements for each column in the spec.
+        val threadCount = lines[0].size
+        assertTrue(lines.all { it.size == threadCount })
+        val threadInstructions = (0 until threadCount).map { i -> lines.map { it[i].trim() } }
+        val barrier = CyclicBarrier(threadCount)
+        var crash: InterpretException? = null
+        threadInstructions.mapIndexed { threadIndex, instructions ->
+            Thread {
+                val threadLocal = threadTransform(initial)
+                barrier.await()
+                var lineNum = 0
+                instructions.forEach {
+                    if (null != crash) return@Thread
+                    lineNum += 1
+                    try {
+                        interpretMultiple(it, threadLocal)
+                    } catch (e: Throwable) {
+                        // If fail() or some exception was called, the thread will come here ; if
+                        // the exception isn't caught the process will crash, which is not nice for
+                        // testing. Instead, catch the exception, cancel other threads, and report
+                        // nicely. Catch throwable because fail() is AssertionError, which inherits
+                        // from Error.
+                        crash = InterpretException(threadIndex, it,
+                                callSite.lineNumber + lineNum + lineShift,
+                                callSite.className, callSite.methodName, callSite.fileName, e)
+                    }
+                    barrier.await()
+                }
+            }.also { it.start() }
+        }.forEach { it.join() }
+        // If the test failed, crash with line number
+        crash?.let { throw it }
+    }
+
+    // Helper to get the stack trace for a calling method
+    private fun getCallingStackTrace(): Array<StackTraceElement> {
+        try {
+            throw RuntimeException()
+        } catch (e: RuntimeException) {
+            return e.stackTrace
+        }
+    }
+
+    // Find the calling method. This is the first method in the stack trace that is annotated
+    // with @Test.
+    fun getCallingMethod(): StackTraceElement {
+        val stackTrace = getCallingStackTrace()
+        return stackTrace.find { element ->
+            val clazz = Class.forName(element.className)
+            // Because the stack trace doesn't list the formal arguments, find all methods with
+            // this name and return this name if any of them is annotated with @Test.
+            clazz.declaredMethods
+                    .filter { method -> method.name == element.methodName }
+                    .any { method -> method.getAnnotation(org.junit.Test::class.java) != null }
+        } ?: stackTrace[3]
+        // If no method is annotated return the 4th one, because that's what it usually is :
+        // 0 is getCallingStackTrace, 1 is this method, 2 is ConcurrentInterpreter#interpretTestSpec
+    }
+}
+
+private fun <T> getDefaultInstructions() = listOf<InterpretMatcher<T>>(
+    // Interpret an empty line as doing nothing.
+    Regex("") to { _, _, _ -> null },
+    // Ignore comments.
+    Regex("(.*)//.*") to { i, t, r -> i.interpret(r.strArg(1), t) },
+    // Interpret "XXX time x..y" : run XXX and check it took at least x and not more than y
+    Regex("""(.*)\s*time\s*(\d+)\.\.(\d+)""") to { i, t, r ->
+        val time = measureTimeMillis { i.interpret(r.strArg(1), t) }
+        assertTrue(time in r.timeArg(2)..r.timeArg(3), "$time not in ${r.timeArg(2)..r.timeArg(3)}")
+    },
+    // Interpret "XXX = YYY" : run XXX and assert its return value is equal to YYY. "null" supported
+    Regex("""(.*)\s*=\s*(null|\d+)""") to { i, t, r ->
+        i.interpret(r.strArg(1), t).also {
+            if ("null" == r.strArg(2)) assertNull(it) else assertEquals(r.intArg(2), it)
+        }
+    },
+    // Interpret sleep. Optional argument for the count, in INTERPRET_TIME_UNIT units.
+    Regex("""sleep(\((\d+)\))?""") to { i, t, r ->
+        SystemClock.sleep(if (r.strArg(2).isEmpty()) i.interpretTimeUnit else r.timeArg(2))
+    },
+    Regex("""(.*)\s*fails""") to { i, t, r ->
+        assertFails { i.interpret(r.strArg(1), t) }
+    }
+)
+
+class SyntaxException(msg: String, cause: Throwable? = null) : RuntimeException(msg, cause)
+class InterpretException(
+    threadIndex: Int,
+    instr: String,
+    lineNum: Int,
+    className: String,
+    methodName: String,
+    fileName: String,
+    cause: Throwable
+) : RuntimeException("Failure: $instr", cause) {
+    init {
+        stackTrace = arrayOf(StackTraceElement(
+                className,
+                "$methodName:thread$threadIndex",
+                fileName,
+                lineNum)) + super.getStackTrace()
+    }
+}
+
+// Some small helpers to avoid to say the large ".groupValues[index].trim()" every time
+fun MatchResult.strArg(index: Int) = this.groupValues[index].trim()
+fun MatchResult.intArg(index: Int) = strArg(index).toInt()
+fun MatchResult.timeArg(index: Int) = INTERPRET_TIME_UNIT * intArg(index)
diff --git a/staticlibs/devicetests/com/android/testutils/DevSdkIgnoreRule.kt b/staticlibs/devicetests/com/android/testutils/DevSdkIgnoreRule.kt
new file mode 100644
index 0000000..4a83f6f
--- /dev/null
+++ b/staticlibs/devicetests/com/android/testutils/DevSdkIgnoreRule.kt
@@ -0,0 +1,90 @@
+/*
+ * Copyright (C) 2020 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 com.android.testutils
+
+import android.os.Build
+import org.junit.Assume.assumeTrue
+import org.junit.rules.TestRule
+import org.junit.runner.Description
+import org.junit.runners.model.Statement
+
+/**
+ * Returns true if the development SDK version of the device is in the provided range.
+ *
+ * If the device is not using a release SDK, the development SDK is considered to be higher than
+ * [Build.VERSION.SDK_INT].
+ */
+fun isDevSdkInRange(minExclusive: Int?, maxInclusive: Int?): Boolean {
+    // In-development API n+1 will have SDK_INT == n and CODENAME != REL.
+    // Stable API n has SDK_INT == n and CODENAME == REL.
+    val release = "REL" == Build.VERSION.CODENAME
+    val sdkInt = Build.VERSION.SDK_INT
+    val devApiLevel = sdkInt + if (release) 0 else 1
+
+    return (minExclusive == null || devApiLevel > minExclusive) &&
+            (maxInclusive == null || devApiLevel <= maxInclusive)
+}
+
+/**
+ * A test rule to ignore tests based on the development SDK level.
+ *
+ * If the device is not using a release SDK, the development SDK is considered to be higher than
+ * [Build.VERSION.SDK_INT].
+ *
+ * @param ignoreClassUpTo Skip all tests in the class if the device dev SDK is <= this value.
+ * @param ignoreClassAfter Skip all tests in the class if the device dev SDK is > this value.
+ */
+class DevSdkIgnoreRule @JvmOverloads constructor(
+    private val ignoreClassUpTo: Int? = null,
+    private val ignoreClassAfter: Int? = null
+) : TestRule {
+    override fun apply(base: Statement, description: Description): Statement {
+        return IgnoreBySdkStatement(base, description)
+    }
+
+    /**
+     * Ignore the test for any development SDK that is strictly after [value].
+     *
+     * If the device is not using a release SDK, the development SDK is considered to be higher
+     * than [Build.VERSION.SDK_INT].
+     */
+    annotation class IgnoreAfter(val value: Int)
+
+    /**
+     * Ignore the test for any development SDK that lower than or equal to [value].
+     *
+     * If the device is not using a release SDK, the development SDK is considered to be higher
+     * than [Build.VERSION.SDK_INT].
+     */
+    annotation class IgnoreUpTo(val value: Int)
+
+    private inner class IgnoreBySdkStatement(
+        private val base: Statement,
+        private val description: Description
+    ) : Statement() {
+        override fun evaluate() {
+            val ignoreAfter = description.getAnnotation(IgnoreAfter::class.java)
+            val ignoreUpTo = description.getAnnotation(IgnoreUpTo::class.java)
+
+            val message = "Skipping test for build ${Build.VERSION.CODENAME} " +
+                    "with SDK ${Build.VERSION.SDK_INT}"
+            assumeTrue(message, isDevSdkInRange(ignoreClassUpTo, ignoreClassAfter))
+            assumeTrue(message, isDevSdkInRange(ignoreUpTo?.value, ignoreAfter?.value))
+            base.evaluate()
+        }
+    }
+}
\ No newline at end of file
diff --git a/staticlibs/devicetests/com/android/testutils/DevSdkIgnoreRunner.kt b/staticlibs/devicetests/com/android/testutils/DevSdkIgnoreRunner.kt
new file mode 100644
index 0000000..73b2843
--- /dev/null
+++ b/staticlibs/devicetests/com/android/testutils/DevSdkIgnoreRunner.kt
@@ -0,0 +1,72 @@
+/*
+ * Copyright (C) 2020 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 com.android.testutils
+
+import androidx.test.ext.junit.runners.AndroidJUnit4
+import com.android.testutils.DevSdkIgnoreRule.IgnoreAfter
+import com.android.testutils.DevSdkIgnoreRule.IgnoreUpTo
+import org.junit.runner.Description
+import org.junit.runner.Runner
+import org.junit.runner.notification.RunNotifier
+
+/**
+ * A runner that can skip tests based on the development SDK as defined in [DevSdkIgnoreRule].
+ *
+ * Generally [DevSdkIgnoreRule] should be used for that purpose (using rules is preferable over
+ * replacing the test runner), however JUnit runners inspect all methods in the test class before
+ * processing test rules. This may cause issues if the test methods are referencing classes that do
+ * not exist on the SDK of the device the test is run on.
+ *
+ * This runner inspects [IgnoreAfter] and [IgnoreUpTo] annotations on the test class, and will skip
+ * the whole class if they do not match the development SDK as defined in [DevSdkIgnoreRule].
+ * Otherwise, it will delegate to [AndroidJUnit4] to run the test as usual.
+ *
+ * Example usage:
+ *
+ *     @RunWith(DevSdkIgnoreRunner::class)
+ *     @IgnoreUpTo(Build.VERSION_CODES.Q)
+ *     class MyTestClass { ... }
+ */
+class DevSdkIgnoreRunner(private val klass: Class<*>) : Runner() {
+    private val baseRunner = klass.let {
+        val ignoreAfter = it.getAnnotation(IgnoreAfter::class.java)
+        val ignoreUpTo = it.getAnnotation(IgnoreUpTo::class.java)
+
+        if (isDevSdkInRange(ignoreUpTo?.value, ignoreAfter?.value)) AndroidJUnit4(klass) else null
+    }
+
+    override fun run(notifier: RunNotifier) {
+        if (baseRunner != null) {
+            baseRunner.run(notifier)
+            return
+        }
+
+        // Report a single, skipped placeholder test for this class, so that the class is still
+        // visible as skipped in test results.
+        notifier.fireTestIgnored(
+                Description.createTestDescription(klass, "skippedClassForDevSdkMismatch"))
+    }
+
+    override fun getDescription(): Description {
+        return baseRunner?.description ?: Description.createSuiteDescription(klass)
+    }
+
+    override fun testCount(): Int {
+        // When ignoring the tests, a skipped placeholder test is reported, so test count is 1.
+        return baseRunner?.testCount() ?: 1
+    }
+}
\ No newline at end of file
diff --git a/staticlibs/devicetests/com/android/testutils/FakeDns.kt b/staticlibs/devicetests/com/android/testutils/FakeDns.kt
new file mode 100644
index 0000000..825d748
--- /dev/null
+++ b/staticlibs/devicetests/com/android/testutils/FakeDns.kt
@@ -0,0 +1,94 @@
+/*
+ * Copyright (C) 2019 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 com.android.testutils
+
+import android.net.DnsResolver
+import android.net.InetAddresses
+import android.os.Looper
+import android.os.Handler
+import com.android.internal.annotations.GuardedBy
+import java.net.InetAddress
+import java.util.concurrent.Executor
+import org.mockito.invocation.InvocationOnMock
+import org.mockito.Mockito.any
+import org.mockito.Mockito.anyInt
+import org.mockito.Mockito.doAnswer
+
+const val TYPE_UNSPECIFIED = -1
+// TODO: Integrate with NetworkMonitorTest.
+class FakeDns(val mockResolver: DnsResolver) {
+    class DnsEntry(val hostname: String, val type: Int, val addresses: List<InetAddress>) {
+        fun match(host: String, type: Int) = hostname.equals(host) && type == type
+    }
+
+    @GuardedBy("answers")
+    val answers = ArrayList<DnsEntry>()
+
+    fun getAnswer(hostname: String, type: Int): DnsEntry? = synchronized(answers) {
+        return answers.firstOrNull { it.match(hostname, type) }
+    }
+
+    fun setAnswer(hostname: String, answer: Array<String>, type: Int) = synchronized(answers) {
+        val ans = DnsEntry(hostname, type, generateAnswer(answer))
+        // Replace or remove the existing one.
+        when (val index = answers.indexOfFirst { it.match(hostname, type) }) {
+            -1 -> answers.add(ans)
+            else -> answers[index] = ans
+        }
+    }
+
+    private fun generateAnswer(answer: Array<String>) =
+            answer.filterNotNull().map { InetAddresses.parseNumericAddress(it) }
+
+    fun startMocking() {
+        // Mock DnsResolver.query() w/o type
+        doAnswer {
+            mockAnswer(it, 1, -1, 3, 5)
+        }.`when`(mockResolver).query(any() /* network */, any() /* domain */, anyInt() /* flags */,
+                any() /* executor */, any() /* cancellationSignal */, any() /*callback*/)
+        // Mock DnsResolver.query() w/ type
+        doAnswer {
+            mockAnswer(it, 1, 2, 4, 6)
+        }.`when`(mockResolver).query(any() /* network */, any() /* domain */, anyInt() /* nsType */,
+                anyInt() /* flags */, any() /* executor */, any() /* cancellationSignal */,
+        any() /*callback*/)
+    }
+
+    private fun mockAnswer(
+        it: InvocationOnMock,
+        posHos: Int,
+        posType: Int,
+        posExecutor: Int,
+        posCallback: Int
+    ) {
+        val hostname = it.arguments[posHos] as String
+        val executor = it.arguments[posExecutor] as Executor
+        val callback = it.arguments[posCallback] as DnsResolver.Callback<List<InetAddress>>
+        var type = if (posType != -1) it.arguments[posType] as Int else TYPE_UNSPECIFIED
+        val answer = getAnswer(hostname, type)
+
+        if (!answer?.addresses.isNullOrEmpty()) {
+            Handler(Looper.getMainLooper()).post({ executor.execute({
+                    callback.onAnswer(answer?.addresses, 0); }) })
+        }
+    }
+
+    /** Clears all entries. */
+    fun clearAll() = synchronized(answers) {
+        answers.clear()
+    }
+}
diff --git a/staticlibs/devicetests/com/android/testutils/HandlerUtils.kt b/staticlibs/devicetests/com/android/testutils/HandlerUtils.kt
new file mode 100644
index 0000000..fa36209
--- /dev/null
+++ b/staticlibs/devicetests/com/android/testutils/HandlerUtils.kt
@@ -0,0 +1,49 @@
+/*
+ * Copyright (C) 2019 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 com.android.testutils
+
+import android.os.ConditionVariable
+import android.os.Handler
+import android.os.HandlerThread
+import java.util.concurrent.Executor
+import kotlin.system.measureTimeMillis
+import kotlin.test.fail
+
+/**
+ * Block until the specified Handler or HandlerThread becomes idle, or until timeoutMs has passed.
+ */
+fun HandlerThread.waitForIdle(timeoutMs: Int) = threadHandler.waitForIdle(timeoutMs.toLong())
+fun HandlerThread.waitForIdle(timeoutMs: Long) = threadHandler.waitForIdle(timeoutMs)
+fun Handler.waitForIdle(timeoutMs: Int) = waitForIdle(timeoutMs.toLong())
+fun Handler.waitForIdle(timeoutMs: Long) {
+    val cv = ConditionVariable(false)
+    post(cv::open)
+    if (!cv.block(timeoutMs)) {
+        fail("Handler did not become idle after ${timeoutMs}ms")
+    }
+}
+
+/**
+ * Block until the given Serial Executor becomes idle, or until timeoutMs has passed.
+ */
+fun waitForIdleSerialExecutor(executor: Executor, timeoutMs: Long) {
+    val cv = ConditionVariable()
+    executor.execute(cv::open)
+    if (!cv.block(timeoutMs)) {
+        fail("Executor did not become idle after ${timeoutMs}ms")
+    }
+}
diff --git a/staticlibs/devicetests/com/android/testutils/NetworkStatsUtils.kt b/staticlibs/devicetests/com/android/testutils/NetworkStatsUtils.kt
new file mode 100644
index 0000000..8324b25
--- /dev/null
+++ b/staticlibs/devicetests/com/android/testutils/NetworkStatsUtils.kt
@@ -0,0 +1,78 @@
+/*
+ * Copyright (C) 2020 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 com.android.testutils
+
+import android.net.NetworkStats
+import kotlin.test.assertTrue
+
+@JvmOverloads
+fun orderInsensitiveEquals(
+    leftStats: NetworkStats,
+    rightStats: NetworkStats,
+    compareTime: Boolean = false
+): Boolean {
+    if (leftStats == rightStats) return true
+    if (compareTime && leftStats.getElapsedRealtime() != rightStats.getElapsedRealtime()) {
+        return false
+    }
+
+    // While operations such as add/subtract will preserve empty entries. This will make
+    // the result be hard to verify during test. Remove them before comparing since they
+    // are not really affect correctness.
+    // TODO (b/152827872): Remove empty entries after addition/subtraction.
+    val leftTrimmedEmpty = leftStats.removeEmptyEntries()
+    val rightTrimmedEmpty = rightStats.removeEmptyEntries()
+
+    if (leftTrimmedEmpty.size() != rightTrimmedEmpty.size()) return false
+    val left = NetworkStats.Entry()
+    val right = NetworkStats.Entry()
+    // Order insensitive compare.
+    for (i in 0 until leftTrimmedEmpty.size()) {
+        leftTrimmedEmpty.getValues(i, left)
+        val j: Int = rightTrimmedEmpty.findIndexHinted(left.iface, left.uid, left.set, left.tag,
+                left.metered, left.roaming, left.defaultNetwork, i)
+        if (j == -1) return false
+        rightTrimmedEmpty.getValues(j, right)
+        if (left != right) return false
+    }
+    return true
+}
+
+/**
+ * Assert that two {@link NetworkStats} are equals, assuming the order of the records are not
+ * necessarily the same.
+ *
+ * @note {@code elapsedRealtime} is not compared by default, given that in test cases that is not
+ *       usually used.
+ */
+@JvmOverloads
+fun assertNetworkStatsEquals(
+    expected: NetworkStats,
+    actual: NetworkStats,
+    compareTime: Boolean = false
+) {
+    assertTrue(orderInsensitiveEquals(expected, actual, compareTime),
+            "expected: " + expected + " but was: " + actual)
+}
+
+/**
+ * Assert that after being parceled then unparceled, {@link NetworkStats} is equal to the original
+ * object.
+ */
+fun assertParcelingIsLossless(stats: NetworkStats) {
+    assertParcelingIsLossless(stats, { a, b -> orderInsensitiveEquals(a, b) })
+}
diff --git a/staticlibs/devicetests/com/android/testutils/ParcelUtils.kt b/staticlibs/devicetests/com/android/testutils/ParcelUtils.kt
new file mode 100644
index 0000000..5784f7c
--- /dev/null
+++ b/staticlibs/devicetests/com/android/testutils/ParcelUtils.kt
@@ -0,0 +1,68 @@
+/*
+ * Copyright (C) 2019 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 com.android.testutils
+
+import android.os.Parcel
+import android.os.Parcelable
+import kotlin.test.assertTrue
+import kotlin.test.fail
+
+/**
+ * Return a new instance of `T` after being parceled then unparceled.
+ */
+fun <T : Parcelable> parcelingRoundTrip(source: T): T {
+    val creator: Parcelable.Creator<T>
+    try {
+        creator = source.javaClass.getField("CREATOR").get(null) as Parcelable.Creator<T>
+    } catch (e: IllegalAccessException) {
+        fail("Missing CREATOR field: " + e.message)
+    } catch (e: NoSuchFieldException) {
+        fail("Missing CREATOR field: " + e.message)
+    }
+
+    var p = Parcel.obtain()
+    source.writeToParcel(p, /* flags */ 0)
+    p.setDataPosition(0)
+    val marshalled = p.marshall()
+    p = Parcel.obtain()
+    p.unmarshall(marshalled, 0, marshalled.size)
+    p.setDataPosition(0)
+    return creator.createFromParcel(p)
+}
+
+/**
+ * Assert that after being parceled then unparceled, `source` is equal to the original
+ * object. If a customized equals function is provided, uses the provided one.
+ */
+@JvmOverloads
+fun <T : Parcelable> assertParcelingIsLossless(
+    source: T,
+    equals: (T, T) -> Boolean = { a, b -> a == b }
+) {
+    val actual = parcelingRoundTrip(source)
+    assertTrue(equals(source, actual), "Expected $source, but was $actual")
+}
+
+@JvmOverloads
+fun <T : Parcelable> assertParcelSane(
+    obj: T,
+    fieldCount: Int,
+    equals: (T, T) -> Boolean = { a, b -> a == b }
+) {
+    assertFieldCountEquals(fieldCount, obj::class.java)
+    assertParcelingIsLossless(obj, equals)
+}
diff --git a/staticlibs/devicetests/com/android/testutils/TapPacketReader.java b/staticlibs/devicetests/com/android/testutils/TapPacketReader.java
new file mode 100644
index 0000000..fea1cd9
--- /dev/null
+++ b/staticlibs/devicetests/com/android/testutils/TapPacketReader.java
@@ -0,0 +1,93 @@
+/*
+ * Copyright (C) 2020 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 com.android.testutils;
+
+import android.net.util.PacketReader;
+import android.os.Handler;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+
+import com.android.net.module.util.ArrayTrackRecord;
+
+import java.io.FileDescriptor;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.nio.ByteBuffer;
+import java.util.Arrays;
+import java.util.function.Predicate;
+
+import kotlin.Lazy;
+import kotlin.LazyKt;
+
+public class TapPacketReader extends PacketReader {
+    private final FileDescriptor mTapFd;
+    private final ArrayTrackRecord<byte[]> mReceivedPackets = new ArrayTrackRecord<>();
+    private final Lazy<ArrayTrackRecord<byte[]>.ReadHead> mReadHead =
+            LazyKt.lazy(mReceivedPackets::newReadHead);
+
+    public TapPacketReader(Handler h, FileDescriptor tapFd, int maxPacketSize) {
+        super(h, maxPacketSize);
+        mTapFd = tapFd;
+    }
+
+    @Override
+    protected FileDescriptor createFd() {
+        return mTapFd;
+    }
+
+    @Override
+    protected void handlePacket(byte[] recvbuf, int length) {
+        final byte[] newPacket = Arrays.copyOf(recvbuf, length);
+        if (!mReceivedPackets.add(newPacket)) {
+            throw new AssertionError("More than " + Integer.MAX_VALUE + " packets outstanding!");
+        }
+    }
+
+    /**
+     * Get the next packet that was received on the interface.
+     */
+    @Nullable
+    public byte[] popPacket(long timeoutMs) {
+        return mReadHead.getValue().poll(timeoutMs, packet -> true);
+    }
+
+    /**
+     * Get the next packet that was received on the interface and matches the specified filter.
+     */
+    @Nullable
+    public byte[] popPacket(long timeoutMs, @NonNull Predicate<byte[]> filter) {
+        return mReadHead.getValue().poll(timeoutMs, filter::test);
+    }
+
+    /**
+     * Get the {@link ArrayTrackRecord} that records all packets received by the reader since its
+     * creation.
+     */
+    public ArrayTrackRecord<byte[]> getReceivedPackets() {
+        return mReceivedPackets;
+    }
+
+    public void sendResponse(final ByteBuffer packet) throws IOException {
+        try (FileOutputStream out = new FileOutputStream(mTapFd)) {
+            byte[] packetBytes = new byte[packet.limit()];
+            packet.get(packetBytes);
+            packet.flip();  // So we can reuse it in the future.
+            out.write(packetBytes);
+        }
+    }
+}
diff --git a/staticlibs/devicetests/com/android/testutils/TestNetworkTracker.kt b/staticlibs/devicetests/com/android/testutils/TestNetworkTracker.kt
new file mode 100644
index 0000000..4bd9ae8
--- /dev/null
+++ b/staticlibs/devicetests/com/android/testutils/TestNetworkTracker.kt
@@ -0,0 +1,92 @@
+/*
+ * Copyright (C) 2020 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 com.android.testutils
+
+import android.content.Context
+import android.net.ConnectivityManager
+import android.net.ConnectivityManager.NetworkCallback
+import android.net.LinkAddress
+import android.net.Network
+import android.net.NetworkCapabilities
+import android.net.NetworkRequest
+import android.net.StringNetworkSpecifier
+import android.net.TestNetworkInterface
+import android.net.TestNetworkManager
+import android.os.Binder
+import java.util.concurrent.CompletableFuture
+import java.util.concurrent.TimeUnit
+
+/**
+ * Create a test network based on a TUN interface.
+ *
+ * This method will block until the test network is available. Requires
+ * [android.Manifest.permission.CHANGE_NETWORK_STATE] and
+ * [android.Manifest.permission.MANAGE_TEST_NETWORKS].
+ */
+fun initTestNetwork(context: Context, interfaceAddr: LinkAddress, setupTimeoutMs: Long = 10_000L):
+        TestNetworkTracker {
+    val tnm = context.getSystemService(TestNetworkManager::class.java)
+    val iface = tnm.createTunInterface(arrayOf(interfaceAddr))
+    return TestNetworkTracker(context, iface, tnm, setupTimeoutMs)
+}
+
+/**
+ * Utility class to create and track test networks.
+ *
+ * This class is not thread-safe.
+ */
+class TestNetworkTracker internal constructor(
+    val context: Context,
+    val iface: TestNetworkInterface,
+    tnm: TestNetworkManager,
+    setupTimeoutMs: Long
+) {
+    private val cm = context.getSystemService(ConnectivityManager::class.java)
+    private val binder = Binder()
+
+    private val networkCallback: NetworkCallback
+    val network: Network
+
+    init {
+        val networkFuture = CompletableFuture<Network>()
+        val networkRequest = NetworkRequest.Builder()
+                .addTransportType(NetworkCapabilities.TRANSPORT_TEST)
+                // Test networks do not have NOT_VPN or TRUSTED capabilities by default
+                .removeCapability(NetworkCapabilities.NET_CAPABILITY_NOT_VPN)
+                .removeCapability(NetworkCapabilities.NET_CAPABILITY_TRUSTED)
+                .setNetworkSpecifier(StringNetworkSpecifier(iface.interfaceName))
+                .build()
+        networkCallback = object : NetworkCallback() {
+            override fun onAvailable(network: Network) {
+                networkFuture.complete(network)
+            }
+        }
+        cm.requestNetwork(networkRequest, networkCallback)
+
+        try {
+            tnm.setupTestNetwork(iface.interfaceName, binder)
+            network = networkFuture.get(setupTimeoutMs, TimeUnit.MILLISECONDS)
+        } catch (e: Throwable) {
+            teardown()
+            throw e
+        }
+    }
+
+    fun teardown() {
+        cm.unregisterNetworkCallback(networkCallback)
+    }
+}
\ No newline at end of file
diff --git a/staticlibs/devicetests/com/android/testutils/TestableNetworkCallback.kt b/staticlibs/devicetests/com/android/testutils/TestableNetworkCallback.kt
new file mode 100644
index 0000000..959a837
--- /dev/null
+++ b/staticlibs/devicetests/com/android/testutils/TestableNetworkCallback.kt
@@ -0,0 +1,393 @@
+/*
+ * Copyright (C) 2019 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 com.android.testutils
+
+import android.net.ConnectivityManager.NetworkCallback
+import android.net.LinkProperties
+import android.net.Network
+import android.net.NetworkCapabilities
+import android.net.NetworkCapabilities.NET_CAPABILITY_VALIDATED
+import com.android.net.module.util.ArrayTrackRecord
+import com.android.testutils.RecorderCallback.CallbackEntry.Available
+import com.android.testutils.RecorderCallback.CallbackEntry.BlockedStatus
+import com.android.testutils.RecorderCallback.CallbackEntry.CapabilitiesChanged
+import com.android.testutils.RecorderCallback.CallbackEntry.LinkPropertiesChanged
+import com.android.testutils.RecorderCallback.CallbackEntry.Losing
+import com.android.testutils.RecorderCallback.CallbackEntry.Lost
+import com.android.testutils.RecorderCallback.CallbackEntry.Resumed
+import com.android.testutils.RecorderCallback.CallbackEntry.Suspended
+import com.android.testutils.RecorderCallback.CallbackEntry.Unavailable
+import kotlin.reflect.KClass
+import kotlin.test.assertEquals
+import kotlin.test.assertNotNull
+import kotlin.test.assertTrue
+import kotlin.test.fail
+
+object NULL_NETWORK : Network(-1)
+object ANY_NETWORK : Network(-2)
+
+private val Int.capabilityName get() = NetworkCapabilities.capabilityNameOf(this)
+
+open class RecorderCallback private constructor(
+    private val backingRecord: ArrayTrackRecord<CallbackEntry>
+) : NetworkCallback() {
+    public constructor() : this(ArrayTrackRecord())
+    protected constructor(src: RecorderCallback?): this(src?.backingRecord ?: ArrayTrackRecord())
+
+    sealed class CallbackEntry {
+        // To get equals(), hashcode(), componentN() etc for free, the child classes of
+        // this class are data classes. But while data classes can inherit from other classes,
+        // they may only have visible members in the constructors, so they couldn't declare
+        // a constructor with a non-val arg to pass to CallbackEntry. Instead, force all
+        // subclasses to implement a `network' property, which can be done in a data class
+        // constructor by specifying override.
+        abstract val network: Network
+
+        data class Available(override val network: Network) : CallbackEntry()
+        data class CapabilitiesChanged(
+            override val network: Network,
+            val caps: NetworkCapabilities
+        ) : CallbackEntry()
+        data class LinkPropertiesChanged(
+            override val network: Network,
+            val lp: LinkProperties
+        ) : CallbackEntry()
+        data class Suspended(override val network: Network) : CallbackEntry()
+        data class Resumed(override val network: Network) : CallbackEntry()
+        data class Losing(override val network: Network, val maxMsToLive: Int) : CallbackEntry()
+        data class Lost(override val network: Network) : CallbackEntry()
+        data class Unavailable private constructor(
+            override val network: Network
+        ) : CallbackEntry() {
+            constructor() : this(NULL_NETWORK)
+        }
+        data class BlockedStatus(
+            override val network: Network,
+            val blocked: Boolean
+        ) : CallbackEntry()
+
+        // Convenience constants for expecting a type
+        companion object {
+            @JvmField
+            val AVAILABLE = Available::class
+            @JvmField
+            val NETWORK_CAPS_UPDATED = CapabilitiesChanged::class
+            @JvmField
+            val LINK_PROPERTIES_CHANGED = LinkPropertiesChanged::class
+            @JvmField
+            val SUSPENDED = Suspended::class
+            @JvmField
+            val RESUMED = Resumed::class
+            @JvmField
+            val LOSING = Losing::class
+            @JvmField
+            val LOST = Lost::class
+            @JvmField
+            val UNAVAILABLE = Unavailable::class
+            @JvmField
+            val BLOCKED_STATUS = BlockedStatus::class
+        }
+    }
+
+    val history = backingRecord.newReadHead()
+    val mark get() = history.mark
+
+    override fun onAvailable(network: Network) {
+        history.add(Available(network))
+    }
+
+    // PreCheck is not used in the tests today. For backward compatibility with existing tests that
+    // expect the callbacks not to record this, do not listen to PreCheck here.
+
+    override fun onCapabilitiesChanged(network: Network, caps: NetworkCapabilities) {
+        history.add(CapabilitiesChanged(network, caps))
+    }
+
+    override fun onLinkPropertiesChanged(network: Network, lp: LinkProperties) {
+        history.add(LinkPropertiesChanged(network, lp))
+    }
+
+    override fun onBlockedStatusChanged(network: Network, blocked: Boolean) {
+        history.add(BlockedStatus(network, blocked))
+    }
+
+    override fun onNetworkSuspended(network: Network) {
+        history.add(Suspended(network))
+    }
+
+    override fun onNetworkResumed(network: Network) {
+        history.add(Resumed(network))
+    }
+
+    override fun onLosing(network: Network, maxMsToLive: Int) {
+        history.add(Losing(network, maxMsToLive))
+    }
+
+    override fun onLost(network: Network) {
+        history.add(Lost(network))
+    }
+
+    override fun onUnavailable() {
+        history.add(Unavailable())
+    }
+}
+
+private const val DEFAULT_TIMEOUT = 200L // ms
+
+open class TestableNetworkCallback private constructor(
+    src: TestableNetworkCallback?,
+    val defaultTimeoutMs: Long = DEFAULT_TIMEOUT
+) : RecorderCallback(src) {
+    @JvmOverloads
+    constructor(timeoutMs: Long = DEFAULT_TIMEOUT): this(null, timeoutMs)
+
+    fun createLinkedCopy() = TestableNetworkCallback(this, defaultTimeoutMs)
+
+    // The last available network, or null if any network was lost since the last call to
+    // onAvailable. TODO : fix this by fixing the tests that rely on this behavior
+    val lastAvailableNetwork: Network?
+        get() = when (val it = history.lastOrNull { it is Available || it is Lost }) {
+            is Available -> it.network
+            else -> null
+        }
+
+    fun pollForNextCallback(timeoutMs: Long = defaultTimeoutMs): CallbackEntry {
+        return history.poll(timeoutMs) ?: fail("Did not receive callback after ${timeoutMs}ms")
+    }
+
+    // Make open for use in ConnectivityServiceTest which is the only one knowing its handlers.
+    @JvmOverloads
+    open fun assertNoCallback(timeoutMs: Long = defaultTimeoutMs) {
+        val cb = history.poll(timeoutMs)
+        if (null != cb) fail("Expected no callback but got $cb")
+    }
+
+    // Expects a callback of the specified type on the specified network within the timeout.
+    // If no callback arrives, or a different callback arrives, fail. Returns the callback.
+    inline fun <reified T : CallbackEntry> expectCallback(
+        network: Network = ANY_NETWORK,
+        timeoutMs: Long = defaultTimeoutMs
+    ): T = pollForNextCallback(timeoutMs).let {
+        if (it !is T || (ANY_NETWORK !== network && it.network != network)) {
+            fail("Unexpected callback : $it, expected ${T::class} with Network[$network]")
+        } else {
+            it
+        }
+    }
+
+    // Expects a callback of the specified type matching the predicate within the timeout.
+    // Any callback that doesn't match the predicate will be skipped. Fails only if
+    // no matching callback is received within the timeout.
+    inline fun <reified T : CallbackEntry> eventuallyExpect(
+        timeoutMs: Long = defaultTimeoutMs,
+        from: Int = mark,
+        crossinline predicate: (T) -> Boolean = { true }
+    ): T = eventuallyExpectOrNull(timeoutMs, from, predicate).also {
+        assertNotNull(it, "Callback ${T::class} not received within ${timeoutMs}ms")
+    } as T
+
+    // TODO (b/157405399) straighten and unify the method names
+    inline fun <reified T : CallbackEntry> eventuallyExpectOrNull(
+        timeoutMs: Long = defaultTimeoutMs,
+        from: Int = mark,
+        crossinline predicate: (T) -> Boolean = { true }
+    ) = history.poll(timeoutMs, from) { it is T && predicate(it) } as T?
+
+    fun expectCallbackThat(
+        timeoutMs: Long = defaultTimeoutMs,
+        valid: (CallbackEntry) -> Boolean
+    ) = pollForNextCallback(timeoutMs).also { assertTrue(valid(it), "Unexpected callback : $it") }
+
+    fun expectCapabilitiesThat(
+        net: Network,
+        tmt: Long = defaultTimeoutMs,
+        valid: (NetworkCapabilities) -> Boolean
+    ): CapabilitiesChanged {
+        return expectCallback<CapabilitiesChanged>(net, tmt).also {
+            assertTrue(valid(it.caps), "Capabilities don't match expectations ${it.caps}")
+        }
+    }
+
+    fun expectLinkPropertiesThat(
+        net: Network,
+        tmt: Long = defaultTimeoutMs,
+        valid: (LinkProperties) -> Boolean
+    ): LinkPropertiesChanged {
+        return expectCallback<LinkPropertiesChanged>(net, tmt).also {
+            assertTrue(valid(it.lp), "LinkProperties don't match expectations ${it.lp}")
+        }
+    }
+
+    // Expects onAvailable and the callbacks that follow it. These are:
+    // - onSuspended, iff the network was suspended when the callbacks fire.
+    // - onCapabilitiesChanged.
+    // - onLinkPropertiesChanged.
+    // - onBlockedStatusChanged.
+    //
+    // @param network the network to expect the callbacks on.
+    // @param suspended whether to expect a SUSPENDED callback.
+    // @param validated the expected value of the VALIDATED capability in the
+    //        onCapabilitiesChanged callback.
+    // @param tmt how long to wait for the callbacks.
+    fun expectAvailableCallbacks(
+        net: Network,
+        suspended: Boolean = false,
+        validated: Boolean = true,
+        blocked: Boolean = false,
+        tmt: Long = defaultTimeoutMs
+    ) {
+        expectCallback<Available>(net, tmt)
+        if (suspended) {
+            expectCallback<Suspended>(net, tmt)
+        }
+        expectCapabilitiesThat(net, tmt) { validated == it.hasCapability(NET_CAPABILITY_VALIDATED) }
+        expectCallback<LinkPropertiesChanged>(net, tmt)
+        expectBlockedStatusCallback(blocked, net)
+    }
+
+    // Backward compatibility for existing Java code. Use named arguments instead and remove all
+    // these when there is no user left.
+    fun expectAvailableAndSuspendedCallbacks(
+        net: Network,
+        validated: Boolean,
+        tmt: Long = defaultTimeoutMs
+    ) = expectAvailableCallbacks(net, suspended = true, validated = validated, tmt = tmt)
+
+    fun expectBlockedStatusCallback(blocked: Boolean, net: Network, tmt: Long = defaultTimeoutMs) {
+        expectCallback<BlockedStatus>(net, tmt).also {
+            assertEquals(it.blocked, blocked, "Unexpected blocked status ${it.blocked}")
+        }
+    }
+
+    // Expects the available callbacks (where the onCapabilitiesChanged must contain the
+    // VALIDATED capability), plus another onCapabilitiesChanged which is identical to the
+    // one we just sent.
+    // TODO: this is likely a bug. Fix it and remove this method.
+    fun expectAvailableDoubleValidatedCallbacks(net: Network, tmt: Long = defaultTimeoutMs) {
+        val mark = history.mark
+        expectAvailableCallbacks(net, tmt = tmt)
+        val firstCaps = history.poll(tmt, mark) { it is CapabilitiesChanged }
+        assertEquals(firstCaps, expectCallback<CapabilitiesChanged>(net, tmt))
+    }
+
+    // Expects the available callbacks where the onCapabilitiesChanged must not have validated,
+    // then expects another onCapabilitiesChanged that has the validated bit set. This is used
+    // when a network connects and satisfies a callback, and then immediately validates.
+    fun expectAvailableThenValidatedCallbacks(net: Network, tmt: Long = defaultTimeoutMs) {
+        expectAvailableCallbacks(net, validated = false, tmt = tmt)
+        expectCapabilitiesThat(net, tmt) { it.hasCapability(NET_CAPABILITY_VALIDATED) }
+    }
+
+    // Temporary Java compat measure : have MockNetworkAgent implement this so that all existing
+    // calls with networkAgent can be routed through here without moving MockNetworkAgent.
+    // TODO: clean this up, remove this method.
+    interface HasNetwork {
+        val network: Network
+    }
+
+    @JvmOverloads
+    open fun <T : CallbackEntry> expectCallback(
+        type: KClass<T>,
+        n: Network?,
+        timeoutMs: Long = defaultTimeoutMs
+    ) = pollForNextCallback(timeoutMs).also {
+        val network = n ?: NULL_NETWORK
+        // TODO : remove this .java access if the tests ever use kotlin-reflect. At the time of
+        // this writing this would be the only use of this library in the tests.
+        assertTrue(type.java.isInstance(it) && it.network == network,
+                "Unexpected callback : $it, expected ${type.java} with Network[$network]")
+    } as T
+
+    @JvmOverloads
+    open fun <T : CallbackEntry> expectCallback(
+        type: KClass<T>,
+        n: HasNetwork?,
+        timeoutMs: Long = defaultTimeoutMs
+    ) = expectCallback(type, n?.network, timeoutMs)
+
+    fun expectAvailableCallbacks(
+        n: HasNetwork,
+        suspended: Boolean,
+        validated: Boolean,
+        blocked: Boolean,
+        timeoutMs: Long
+    ) = expectAvailableCallbacks(n.network, suspended, validated, blocked, timeoutMs)
+
+    fun expectAvailableAndSuspendedCallbacks(n: HasNetwork, expectValidated: Boolean) {
+        expectAvailableAndSuspendedCallbacks(n.network, expectValidated)
+    }
+
+    fun expectAvailableCallbacksValidated(n: HasNetwork) {
+        expectAvailableCallbacks(n.network)
+    }
+
+    fun expectAvailableCallbacksValidatedAndBlocked(n: HasNetwork) {
+        expectAvailableCallbacks(n.network, blocked = true)
+    }
+
+    fun expectAvailableCallbacksUnvalidated(n: HasNetwork) {
+        expectAvailableCallbacks(n.network, validated = false)
+    }
+
+    fun expectAvailableCallbacksUnvalidatedAndBlocked(n: HasNetwork) {
+        expectAvailableCallbacks(n.network, validated = false, blocked = true)
+    }
+
+    fun expectAvailableDoubleValidatedCallbacks(n: HasNetwork) {
+        expectAvailableDoubleValidatedCallbacks(n.network, defaultTimeoutMs)
+    }
+
+    fun expectAvailableThenValidatedCallbacks(n: HasNetwork) {
+        expectAvailableThenValidatedCallbacks(n.network, defaultTimeoutMs)
+    }
+
+    @JvmOverloads
+    fun expectLinkPropertiesThat(
+        n: HasNetwork,
+        tmt: Long = defaultTimeoutMs,
+        valid: (LinkProperties) -> Boolean
+    ) = expectLinkPropertiesThat(n.network, tmt, valid)
+
+    @JvmOverloads
+    fun expectCapabilitiesThat(
+        n: HasNetwork,
+        tmt: Long = defaultTimeoutMs,
+        valid: (NetworkCapabilities) -> Boolean
+    ) = expectCapabilitiesThat(n.network, tmt, valid)
+
+    @JvmOverloads
+    fun expectCapabilitiesWith(
+        capability: Int,
+        n: HasNetwork,
+        timeoutMs: Long = defaultTimeoutMs
+    ): NetworkCapabilities {
+        return expectCapabilitiesThat(n.network, timeoutMs) { it.hasCapability(capability) }.caps
+    }
+
+    @JvmOverloads
+    fun expectCapabilitiesWithout(
+        capability: Int,
+        n: HasNetwork,
+        timeoutMs: Long = defaultTimeoutMs
+    ): NetworkCapabilities {
+        return expectCapabilitiesThat(n.network, timeoutMs) { !it.hasCapability(capability) }.caps
+    }
+
+    fun expectBlockedStatusCallback(expectBlocked: Boolean, n: HasNetwork) {
+        expectBlockedStatusCallback(expectBlocked, n.network, defaultTimeoutMs)
+    }
+}
diff --git a/staticlibs/devicetests/com/android/testutils/TestableNetworkStatsProvider.kt b/staticlibs/devicetests/com/android/testutils/TestableNetworkStatsProvider.kt
new file mode 100644
index 0000000..d5c3a2a
--- /dev/null
+++ b/staticlibs/devicetests/com/android/testutils/TestableNetworkStatsProvider.kt
@@ -0,0 +1,98 @@
+/*
+ * Copyright (C) 2020 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 com.android.testutils
+
+import android.net.netstats.provider.NetworkStatsProvider
+import com.android.net.module.util.ArrayTrackRecord
+import kotlin.test.assertEquals
+import kotlin.test.assertTrue
+import kotlin.test.fail
+
+private const val DEFAULT_TIMEOUT_MS = 200L
+
+open class TestableNetworkStatsProvider(
+    val defaultTimeoutMs: Long = DEFAULT_TIMEOUT_MS
+) : NetworkStatsProvider() {
+    sealed class CallbackType {
+        data class OnRequestStatsUpdate(val token: Int) : CallbackType()
+        data class OnSetLimit(val iface: String?, val quotaBytes: Long) : CallbackType()
+        data class OnSetAlert(val quotaBytes: Long) : CallbackType()
+    }
+
+    val history = ArrayTrackRecord<CallbackType>().newReadHead()
+    // See ReadHead#mark
+    val mark get() = history.mark
+
+    override fun onRequestStatsUpdate(token: Int) {
+        history.add(CallbackType.OnRequestStatsUpdate(token))
+    }
+
+    override fun onSetLimit(iface: String, quotaBytes: Long) {
+        history.add(CallbackType.OnSetLimit(iface, quotaBytes))
+    }
+
+    override fun onSetAlert(quotaBytes: Long) {
+        history.add(CallbackType.OnSetAlert(quotaBytes))
+    }
+
+    fun expectOnRequestStatsUpdate(token: Int, timeout: Long = defaultTimeoutMs) {
+        assertEquals(CallbackType.OnRequestStatsUpdate(token), history.poll(timeout))
+    }
+
+    fun expectOnSetLimit(iface: String?, quotaBytes: Long, timeout: Long = defaultTimeoutMs) {
+        assertEquals(CallbackType.OnSetLimit(iface, quotaBytes), history.poll(timeout))
+    }
+
+    fun expectOnSetAlert(quotaBytes: Long, timeout: Long = defaultTimeoutMs) {
+        assertEquals(CallbackType.OnSetAlert(quotaBytes), history.poll(timeout))
+    }
+
+    fun pollForNextCallback(timeout: Long = defaultTimeoutMs) =
+        history.poll(timeout) ?: fail("Did not receive callback after ${timeout}ms")
+
+    inline fun <reified T : CallbackType> expectCallback(
+        timeout: Long = defaultTimeoutMs,
+        predicate: (T) -> Boolean = { true }
+    ): T {
+        return pollForNextCallback(timeout).also { assertTrue(it is T && predicate(it)) } as T
+    }
+
+    // Expects a callback of the specified type matching the predicate within the timeout.
+    // Any callback that doesn't match the predicate will be skipped. Fails only if
+    // no matching callback is received within the timeout.
+    // TODO : factorize the code for this with the identical call in TestableNetworkCallback.
+    // There should be a common superclass doing this generically.
+    // TODO : have a better error message to have this fail. Right now the failure when no
+    // matching callback arrives comes from the casting to a non-nullable T.
+    // TODO : in fact, completely removing this method and have clients use
+    // history.poll(timeout, index, predicate) directly might be simpler.
+    inline fun <reified T : CallbackType> eventuallyExpect(
+        timeoutMs: Long = defaultTimeoutMs,
+        from: Int = mark,
+        crossinline predicate: (T) -> Boolean = { true }
+    ) = history.poll(timeoutMs, from) { it is T && predicate(it) } as T
+
+    fun drainCallbacks() {
+        history.mark = history.size
+    }
+
+    @JvmOverloads
+    fun assertNoCallback(timeout: Long = defaultTimeoutMs) {
+        val cb = history.poll(timeout)
+        cb?.let { fail("Expected no callback but got $cb") }
+    }
+}
diff --git a/staticlibs/devicetests/com/android/testutils/TestableNetworkStatsProviderBinder.kt b/staticlibs/devicetests/com/android/testutils/TestableNetworkStatsProviderBinder.kt
new file mode 100644
index 0000000..02922d8
--- /dev/null
+++ b/staticlibs/devicetests/com/android/testutils/TestableNetworkStatsProviderBinder.kt
@@ -0,0 +1,64 @@
+/*
+ * Copyright (C) 2020 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 com.android.testutils
+
+import android.net.netstats.provider.INetworkStatsProvider
+import com.android.net.module.util.ArrayTrackRecord
+import kotlin.test.assertEquals
+import kotlin.test.fail
+
+private const val DEFAULT_TIMEOUT_MS = 200L
+
+open class TestableNetworkStatsProviderBinder : INetworkStatsProvider.Stub() {
+    sealed class CallbackType {
+        data class OnRequestStatsUpdate(val token: Int) : CallbackType()
+        data class OnSetLimit(val iface: String?, val quotaBytes: Long) : CallbackType()
+        data class OnSetAlert(val quotaBytes: Long) : CallbackType()
+    }
+
+    private val history = ArrayTrackRecord<CallbackType>().ReadHead()
+
+    override fun onRequestStatsUpdate(token: Int) {
+        history.add(CallbackType.OnRequestStatsUpdate(token))
+    }
+
+    override fun onSetLimit(iface: String?, quotaBytes: Long) {
+        history.add(CallbackType.OnSetLimit(iface, quotaBytes))
+    }
+
+    override fun onSetAlert(quotaBytes: Long) {
+        history.add(CallbackType.OnSetAlert(quotaBytes))
+    }
+
+    fun expectOnRequestStatsUpdate(token: Int) {
+        assertEquals(CallbackType.OnRequestStatsUpdate(token), history.poll(DEFAULT_TIMEOUT_MS))
+    }
+
+    fun expectOnSetLimit(iface: String?, quotaBytes: Long) {
+        assertEquals(CallbackType.OnSetLimit(iface, quotaBytes), history.poll(DEFAULT_TIMEOUT_MS))
+    }
+
+    fun expectOnSetAlert(quotaBytes: Long) {
+        assertEquals(CallbackType.OnSetAlert(quotaBytes), history.poll(DEFAULT_TIMEOUT_MS))
+    }
+
+    @JvmOverloads
+    fun assertNoCallback(timeout: Long = DEFAULT_TIMEOUT_MS) {
+        val cb = history.poll(timeout)
+        cb?.let { fail("Expected no callback but got $cb") }
+    }
+}
diff --git a/staticlibs/devicetests/com/android/testutils/TestableNetworkStatsProviderCbBinder.kt b/staticlibs/devicetests/com/android/testutils/TestableNetworkStatsProviderCbBinder.kt
new file mode 100644
index 0000000..163473a
--- /dev/null
+++ b/staticlibs/devicetests/com/android/testutils/TestableNetworkStatsProviderCbBinder.kt
@@ -0,0 +1,84 @@
+/*
+ * Copyright (C) 2020 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 com.android.testutils
+
+import android.net.NetworkStats
+import android.net.netstats.provider.INetworkStatsProviderCallback
+import com.android.net.module.util.ArrayTrackRecord
+import kotlin.test.assertEquals
+import kotlin.test.assertTrue
+import kotlin.test.fail
+
+private const val DEFAULT_TIMEOUT_MS = 3000L
+
+open class TestableNetworkStatsProviderCbBinder : INetworkStatsProviderCallback.Stub() {
+    sealed class CallbackType {
+        data class NotifyStatsUpdated(
+            val token: Int,
+            val ifaceStats: NetworkStats,
+            val uidStats: NetworkStats
+        ) : CallbackType()
+        object NotifyLimitReached : CallbackType()
+        object NotifyAlertReached : CallbackType()
+        object Unregister : CallbackType()
+    }
+
+    private val history = ArrayTrackRecord<CallbackType>().ReadHead()
+
+    override fun notifyStatsUpdated(token: Int, ifaceStats: NetworkStats, uidStats: NetworkStats) {
+        history.add(CallbackType.NotifyStatsUpdated(token, ifaceStats, uidStats))
+    }
+
+    override fun notifyLimitReached() {
+        history.add(CallbackType.NotifyLimitReached)
+    }
+
+    override fun notifyAlertReached() {
+        history.add(CallbackType.NotifyAlertReached)
+    }
+
+    override fun unregister() {
+        history.add(CallbackType.Unregister)
+    }
+
+    fun expectNotifyStatsUpdated() {
+        val event = history.poll(DEFAULT_TIMEOUT_MS)
+        assertTrue(event is CallbackType.NotifyStatsUpdated)
+    }
+
+    fun expectNotifyStatsUpdated(ifaceStats: NetworkStats, uidStats: NetworkStats) {
+        val event = history.poll(DEFAULT_TIMEOUT_MS)!!
+        if (event !is CallbackType.NotifyStatsUpdated) {
+            throw Exception("Expected NotifyStatsUpdated callback, but got ${event::class}")
+        }
+        // TODO: verify token.
+        assertNetworkStatsEquals(ifaceStats, event.ifaceStats)
+        assertNetworkStatsEquals(uidStats, event.uidStats)
+    }
+
+    fun expectNotifyLimitReached() =
+            assertEquals(CallbackType.NotifyLimitReached, history.poll(DEFAULT_TIMEOUT_MS))
+
+    fun expectNotifyAlertReached() =
+            assertEquals(CallbackType.NotifyAlertReached, history.poll(DEFAULT_TIMEOUT_MS))
+
+    // Assert there is no callback in current queue.
+    fun assertNoCallback() {
+        val cb = history.poll(0)
+        cb?.let { fail("Expected no callback but got $cb") }
+    }
+}