Move TrackRecordTest to libs/net

/*

 * 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.net.module.util

import com.android.testutils.ConcurrentInterpreter

import com.android.testutils.InterpretException

import com.android.testutils.InterpretMatcher

import com.android.testutils.SyntaxException

import com.android.testutils.__FILE__

import com.android.testutils.__LINE__

import com.android.testutils.intArg

import com.android.testutils.strArg

import com.android.testutils.timeArg

import org.junit.Test

import org.junit.runner.RunWith

import org.junit.runners.JUnit4

import java.util.concurrent.CyclicBarrier

import java.util.concurrent.TimeUnit

import java.util.concurrent.atomic.AtomicInteger

import kotlin.system.measureTimeMillis

import kotlin.test.assertEquals

import kotlin.test.assertFailsWith

import kotlin.test.assertFalse

import kotlin.test.assertNotEquals

import kotlin.test.assertNull

import kotlin.test.assertTrue

import kotlin.test.fail

val TEST_VALUES = listOf(4, 13, 52, 94, 41, 68, 11, 13, 51, 0, 91, 94, 33, 98, 14)

const val ABSENT_VALUE = 2

// Caution in changing these : some tests rely on the fact that TEST_TIMEOUT > 2 * SHORT_TIMEOUT

// and LONG_TIMEOUT > 2 * TEST_TIMEOUT

const val SHORT_TIMEOUT = 40L // ms

const val TEST_TIMEOUT = 200L // ms

const val LONG_TIMEOUT = 5000L // ms

@RunWith(JUnit4::class)

class TrackRecordTest {

    @Test

    fun testAddAndSizeAndGet() {

        val repeats = 22 // arbitrary

        val record = ArrayTrackRecord<Int>()

        assertEquals(0, record.size)

        repeat(repeats) { i -> record.add(i + 2) }

        assertEquals(repeats, record.size)

        record.add(2)

        assertEquals(repeats + 1, record.size)

        assertEquals(11, record[9])

        assertEquals(11, record.getOrNull(9))

        assertEquals(2, record[record.size - 1])

        assertEquals(2, record.getOrNull(record.size - 1))

        assertFailsWith<IndexOutOfBoundsException> { record[800] }

        assertFailsWith<IndexOutOfBoundsException> { record[-1] }

        assertFailsWith<IndexOutOfBoundsException> { record[repeats + 1] }

        assertNull(record.getOrNull(800))

        assertNull(record.getOrNull(-1))

        assertNull(record.getOrNull(repeats + 1))

        assertNull(record.getOrNull(800) { true })

        assertNull(record.getOrNull(-1) { true })

        assertNull(record.getOrNull(repeats + 1) { true })

    }

    @Test

    fun testIndexOf() {

        val record = ArrayTrackRecord<Int>()

        TEST_VALUES.forEach { record.add(it) }

        with(record) {

            assertEquals(9, indexOf(0))

            assertEquals(9, lastIndexOf(0))

            assertEquals(1, indexOf(13))

            assertEquals(7, lastIndexOf(13))

            assertEquals(3, indexOf(94))

            assertEquals(11, lastIndexOf(94))

            assertEquals(-1, indexOf(ABSENT_VALUE))

            assertEquals(-1, lastIndexOf(ABSENT_VALUE))

        }

    }

    @Test

    fun testContains() {

        val record = ArrayTrackRecord<Int>()

        TEST_VALUES.forEach { record.add(it) }

        TEST_VALUES.forEach { assertTrue(record.contains(it)) }

        assertFalse(record.contains(ABSENT_VALUE))

        assertTrue(record.containsAll(TEST_VALUES))

        assertTrue(record.containsAll(TEST_VALUES.sorted()))

        assertTrue(record.containsAll(TEST_VALUES.sortedDescending()))

        assertTrue(record.containsAll(TEST_VALUES.distinct()))

        assertTrue(record.containsAll(TEST_VALUES.subList(0, TEST_VALUES.size / 2)))

        assertTrue(record.containsAll(TEST_VALUES.subList(0, TEST_VALUES.size / 2).sorted()))

        assertTrue(record.containsAll(listOf()))

        assertFalse(record.containsAll(listOf(ABSENT_VALUE)))

        assertFalse(record.containsAll(TEST_VALUES + listOf(ABSENT_VALUE)))

    }

    @Test

    fun testEmpty() {

        val record = ArrayTrackRecord<Int>()

        assertTrue(record.isEmpty())

        record.add(1)

        assertFalse(record.isEmpty())

    }

    @Test

    fun testIterate() {

        val record = ArrayTrackRecord<Int>()

        record.forEach { fail("Expected nothing to iterate") }

        TEST_VALUES.forEach { record.add(it) }

        // zip relies on the iterator (this calls extension function Iterable#zip(Iterable))

        record.zip(TEST_VALUES).forEach { assertEquals(it.first, it.second) }

        // Also test reverse iteration (to test hasPrevious() and friends)

        record.reversed().zip(TEST_VALUES.reversed()).forEach { assertEquals(it.first, it.second) }

    }

    @Test

    fun testIteratorIsSnapshot() {

        val record = ArrayTrackRecord<Int>()

        TEST_VALUES.forEach { record.add(it) }

        val iterator = record.iterator()

        val expectedSize = record.size

        record.add(ABSENT_VALUE)

        record.add(ABSENT_VALUE)

        var measuredSize = 0

        iterator.forEach {

            ++measuredSize

            assertNotEquals(ABSENT_VALUE, it)

        }

        assertEquals(expectedSize, measuredSize)

    }

    @Test

    fun testSublist() {

        val record = ArrayTrackRecord<Int>()

        TEST_VALUES.forEach { record.add(it) }

        assertEquals(record.subList(3, record.size - 3),

                TEST_VALUES.subList(3, TEST_VALUES.size - 3))

    }

    fun testPollReturnsImmediately(record: TrackRecord<Int>) {

        record.add(4)

        val elapsed = measureTimeMillis { assertEquals(4, record.poll(LONG_TIMEOUT, 0)) }

        // Should not have waited at all, in fact.

        assertTrue(elapsed < LONG_TIMEOUT)

        record.add(7)

        record.add(9)

        // Can poll multiple times for the same position, in whatever order

        assertEquals(9, record.poll(0, 2))

        assertEquals(7, record.poll(Long.MAX_VALUE, 1))

        assertEquals(9, record.poll(0, 2))

        assertEquals(4, record.poll(0, 0))

        assertEquals(9, record.poll(0, 2) { it > 5 })

        assertEquals(7, record.poll(0, 0) { it > 5 })

    }

    @Test

    fun testPollReturnsImmediately() {

        testPollReturnsImmediately(ArrayTrackRecord())

        testPollReturnsImmediately(ArrayTrackRecord<Int>().newReadHead())

    }

    @Test

    fun testPollTimesOut() {

        val record = ArrayTrackRecord<Int>()

        var delay = measureTimeMillis { assertNull(record.poll(SHORT_TIMEOUT, 0)) }

        assertTrue(delay >= SHORT_TIMEOUT, "Delay $delay < $SHORT_TIMEOUT")

        delay = measureTimeMillis { assertNull(record.poll(SHORT_TIMEOUT, 0) { it < 10 }) }

        assertTrue(delay >= SHORT_TIMEOUT)

    }

    @Test

    fun testConcurrentPollDisallowed() {

        val failures = AtomicInteger(0)

        val readHead = ArrayTrackRecord<Int>().newReadHead()

        val barrier = CyclicBarrier(2)

        Thread {

            barrier.await(LONG_TIMEOUT, TimeUnit.MILLISECONDS) // barrier 1

            try {

                readHead.poll(LONG_TIMEOUT)

            } catch (e: ConcurrentModificationException) {

                failures.incrementAndGet()

                // Unblock the other thread

                readHead.add(0)

            }

        }.start()

        barrier.await() // barrier 1

        try {

            readHead.poll(LONG_TIMEOUT)

        } catch (e: ConcurrentModificationException) {

            failures.incrementAndGet()

            // Unblock the other thread

            readHead.add(0)

        }

        // One of the threads must have gotten an exception.

        assertEquals(failures.get(), 1)

    }

    @Test

    fun testPollWakesUp() {

        val record = ArrayTrackRecord<Int>()

        val barrier = CyclicBarrier(2)

        Thread {

            barrier.await(LONG_TIMEOUT, TimeUnit.MILLISECONDS) // barrier 1

            barrier.await() // barrier 2

            Thread.sleep(SHORT_TIMEOUT * 2)

            record.add(31)

        }.start()

        barrier.await() // barrier 1

        // Should find the element in more than SHORT_TIMEOUT but less than TEST_TIMEOUT

        var delay = measureTimeMillis {

            barrier.await() // barrier 2

            assertEquals(31, record.poll(TEST_TIMEOUT, 0))

        }

        assertTrue(delay in SHORT_TIMEOUT..TEST_TIMEOUT)

        // Polling for an element already added in anothe thread (pos 0) : should return immediately

        delay = measureTimeMillis { assertEquals(31, record.poll(TEST_TIMEOUT, 0)) }

        assertTrue(delay < TEST_TIMEOUT, "Delay $delay > $TEST_TIMEOUT")

        // Waiting for an element that never comes

        delay = measureTimeMillis { assertNull(record.poll(SHORT_TIMEOUT, 1)) }

        assertTrue(delay >= SHORT_TIMEOUT, "Delay $delay < $SHORT_TIMEOUT")

        // Polling for an element that doesn't match what is already there

        delay = measureTimeMillis { assertNull(record.poll(SHORT_TIMEOUT, 0) { it < 10 }) }

        assertTrue(delay >= SHORT_TIMEOUT)

    }

    // Just make sure the interpreter actually throws an exception when the spec

    // does not conform to the behavior. The interpreter is just a tool to test a

    // tool used for a tool for test, let's not have hundreds of tests for it ;

    // if it's broken one of the tests using it will break.

    @Test

    fun testInterpreter() {

        val interpretLine = __LINE__ + 2

        try {

            TRTInterpreter.interpretTestSpec(useReadHeads = true, spec = """

                add(4) | poll(1, 0) = 5

            """)

            fail("This spec should have thrown")

        } catch (e: InterpretException) {

            assertTrue(e.cause is AssertionError)

            assertEquals(interpretLine + 1, e.stackTrace[0].lineNumber)

            assertTrue(e.stackTrace[0].fileName.contains(__FILE__))

            assertTrue(e.stackTrace[0].methodName.contains("testInterpreter"))

            assertTrue(e.stackTrace[0].methodName.contains("thread1"))

        }

    }

    @Test

    fun testMultipleAdds() {

        TRTInterpreter.interpretTestSpec(useReadHeads = false, spec = """

            add(2)         |                |                |

                           | add(4)         |                |

                           |                | add(6)         |

                           |                |                | add(8)

            poll(0, 0) = 2 time 0..1 | poll(0, 0) = 2 | poll(0, 0) = 2 | poll(0, 0) = 2

            poll(0, 1) = 4 time 0..1 | poll(0, 1) = 4 | poll(0, 1) = 4 | poll(0, 1) = 4

            poll(0, 2) = 6 time 0..1 | poll(0, 2) = 6 | poll(0, 2) = 6 | poll(0, 2) = 6

            poll(0, 3) = 8 time 0..1 | poll(0, 3) = 8 | poll(0, 3) = 8 | poll(0, 3) = 8

        """)

    }

    @Test

    fun testConcurrentAdds() {

        TRTInterpreter.interpretTestSpec(useReadHeads = false, spec = """

            add(2)             | add(4)             | add(6)             | add(8)

            add(1)             | add(3)             | add(5)             | add(7)

            poll(0, 1) is even | poll(0, 0) is even | poll(0, 3) is even | poll(0, 2) is even

            poll(0, 5) is odd  | poll(0, 4) is odd  | poll(0, 7) is odd  | poll(0, 6) is odd

        """)

    }

    @Test

    fun testMultiplePoll() {

        TRTInterpreter.interpretTestSpec(useReadHeads = false, spec = """

            add(4)         | poll(1, 0) = 4

                           | poll(0, 1) = null time 0..1

                           | poll(1, 1) = null time 1..2

            sleep; add(7)  | poll(2, 1) = 7 time 1..2

            sleep; add(18) | poll(2, 2) = 18 time 1..2

        """)

    }

    @Test

    fun testMultiplePollWithPredicate() {

        TRTInterpreter.interpretTestSpec(useReadHeads = false, spec = """

                     | poll(1, 0) = null          | poll(1, 0) = null

            add(6)   | poll(1, 0) = 6             |

            add(11)  | poll(1, 0) { > 20 } = null | poll(1, 0) { = 11 } = 11

                     | poll(1, 0) { > 8 } = 11    |

        """)

    }

    @Test

    fun testMultipleReadHeads() {

        TRTInterpreter.interpretTestSpec(useReadHeads = true, spec = """

                   | poll() = null | poll() = null | poll() = null

            add(5) |               | poll() = 5    |

                   | poll() = 5    |               |

            add(8) | poll() = 8    | poll() = 8    |

                   |               |               | poll() = 5

                   |               |               | poll() = 8

                   |               |               | poll() = null

                   |               | poll() = null |

        """)

    }

    @Test

    fun testReadHeadPollWithPredicate() {

        TRTInterpreter.interpretTestSpec(useReadHeads = true, spec = """

            add(5)  | poll() { < 0 } = null

                    | poll() { > 5 } = null

            add(10) |

                    | poll() { = 5 } = null   // The "5" was skipped in the previous line

            add(15) | poll() { > 8 } = 15     // The "10" was skipped in the previous line

                    | poll(1, 0) { > 8 } = 10 // 10 is the first element after pos 0 matching > 8

        """)

    }

    @Test

    fun testPollImmediatelyAdvancesReadhead() {

        TRTInterpreter.interpretTestSpec(useReadHeads = true, spec = """

            add(1)                  | add(2)              | add(3)   | add(4)

            mark = 0                | poll(0) { > 3 } = 4 |          |

            poll(0) { > 10 } = null |                     |          |

            mark = 4                |                     |          |

            poll() = null           |                     |          |

        """)

    }

    @Test

    fun testParallelReadHeads() {

        TRTInterpreter.interpretTestSpec(useReadHeads = true, spec = """

            mark = 0   | mark = 0   | mark = 0   | mark = 0

            add(2)     |            |            |

                       | add(4)     |            |

                       |            | add(6)     |

                       |            |            | add(8)

            poll() = 2 | poll() = 2 | poll() = 2 | poll() = 2

            poll() = 4 | poll() = 4 | poll() = 4 | poll() = 4

            poll() = 6 | poll() = 6 | poll() = 6 | mark = 2

            poll() = 8 | poll() = 8 | mark = 3   | poll() = 6

            mark = 4   | mark = 4   | poll() = 8 | poll() = 8

        """)

    }

    @Test

    fun testPeek() {

        TRTInterpreter.interpretTestSpec(useReadHeads = true, spec = """

            add(2)     |            |               |

                       | add(4)     |               |

                       |            | add(6)        |

                       |            |               | add(8)

            peek() = 2 | poll() = 2 | poll() = 2    | peek() = 2

            peek() = 2 | peek() = 4 | poll() = 4    | peek() = 2

            peek() = 2 | peek() = 4 | peek() = 6    | poll() = 2

            peek() = 2 | mark = 1   | mark = 2      | poll() = 4

            mark = 0   | peek() = 4 | peek() = 6    | peek() = 6

            poll() = 2 | poll() = 4 | poll() = 6    | poll() = 6

            poll() = 4 | mark = 2   | poll() = 8    | peek() = 8

            peek() = 6 | peek() = 6 | peek() = null | mark = 3

        """)

    }

}

private object TRTInterpreter : ConcurrentInterpreter<TrackRecord<Int>>(interpretTable) {

    fun interpretTestSpec(spec: String, useReadHeads: Boolean) = if (useReadHeads) {

        interpretTestSpec(spec, initial = ArrayTrackRecord(),

                threadTransform = { (it as ArrayTrackRecord).newReadHead() })

    } else {

        interpretTestSpec(spec, ArrayTrackRecord())

    }

}

/*

 * Quick ref of supported expressions :

 * sleep(x) : sleeps for x time units and returns Unit ; sleep alone means sleep(1)

 * add(x) : calls and returns TrackRecord#add.

 * poll(time, pos) [{ predicate }] : calls and returns TrackRecord#poll(x time units, pos).

 *   Optionally, a predicate may be specified.

 * poll() [{ predicate }] : calls and returns ReadHead#poll(1 time unit). Optionally, a predicate

 *   may be specified.

 * 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.

 * predicate must be one of "= x", "< x" or "> x".

 */

private val interpretTable = listOf<InterpretMatcher<TrackRecord<Int>>>(

    // Interpret "XXX is odd" : run XXX and assert its return value is odd ("even" works too)

    Regex("(.*)\\s+is\\s+(even|odd)") to { i, t, r ->

        i.interpret(r.strArg(1), t).also {

            assertEquals((it as Int) % 2, if ("even" == r.strArg(2)) 0 else 1)

        }

    },

    // Interpret "add(XXX)" as TrackRecord#add(int)

    Regex("""add\((\d+)\)""") to { i, t, r ->

        t.add(r.intArg(1))

    },

    // Interpret "poll(x, y)" as TrackRecord#poll(timeout = x * INTERPRET_TIME_UNIT, pos = y)

    // Accepts an optional {} argument for the predicate (see makePredicate for syntax)

    Regex("""poll\((\d+),\s*(\d+)\)\s*(\{.*\})?""") to { i, t, r ->

        t.poll(r.timeArg(1), r.intArg(2), makePredicate(r.strArg(3)))

    },

    // ReadHead#poll. If this throws in the cast, the code is malformed and has passed "poll()"

    // in a test that takes a TrackRecord that is not a ReadHead. It's technically possible to get

    // the test code to not compile instead of throw, but it's vastly more complex and this will

    // fail 100% at runtime any test that would not have compiled.

    Regex("""poll\((\d+)?\)\s*(\{.*\})?""") to { i, t, r ->

        (if (r.strArg(1).isEmpty()) i.interpretTimeUnit else r.timeArg(1)).let { time ->

            (t as ArrayTrackRecord<Int>.ReadHead).poll(time, makePredicate(r.strArg(2)))

        }

    },

    // ReadHead#mark. The same remarks apply as with ReadHead#poll.

    Regex("mark") to { i, t, _ -> (t as ArrayTrackRecord<Int>.ReadHead).mark },

    // ReadHead#peek. The same remarks apply as with ReadHead#poll.

    Regex("peek\\(\\)") to { i, t, _ -> (t as ArrayTrackRecord<Int>.ReadHead).peek() }

)

// Parses a { = x } or { < x } or { > x } string and returns the corresponding predicate

// Returns an always-true predicate for empty and null arguments

private fun makePredicate(spec: String?): (Int) -> Boolean {

    if (spec.isNullOrEmpty()) return { true }

    val match = Regex("""\{\s*([<>=])\s*(\d+)\s*\}""").matchEntire(spec)

            ?: throw SyntaxException("Predicate \"${spec}\"")

    val arg = match.intArg(2)

    return when (match.strArg(1)) {

        ">" -> { i -> i > arg }

        "<" -> { i -> i < arg }

        "=" -> { i -> i == arg }

        else -> throw RuntimeException("How did \"${spec}\" match this regexp ?")

    }

}