common/kotlinx-coroutines-core-common/test/selects/SelectBuilderImplTest.kt

/*
 * Copyright 2016-2017 JetBrains s.r.o.
 *
 * 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 kotlinx.coroutines.experimental.selects

import kotlin.coroutines.experimental.*
import kotlin.coroutines.experimental.intrinsics.*
import kotlin.test.*

class SelectBuilderImplTest {
    @Test
    fun testIdempotentSelectResumeInline() {
        var resumed = false
        val delegate = object : Continuation<String> {
            override val context: CoroutineContext get() = EmptyCoroutineContext
            override fun resume(value: String) {
                check(value === "OK")
                resumed = true
            }
            override fun resumeWithException(exception: Throwable) { error("Should not happen") }
        }
        val c = SelectBuilderImpl(delegate)
        // still running builder
        check(!c.isSelected)
        check(c.trySelect("SELECT"))
        check(c.isSelected)
        check(!c.trySelect("OTHER"))
        check(c.trySelect("SELECT"))
        c.completion.resume("OK")
        check(!resumed) // still running builder, didn't invoke delegate
        check(c.isSelected)
        check(!c.trySelect("OTHER"))
        check(c.trySelect("SELECT"))
        check(c.getResult() === "OK") // then builder returns
    }

    @Test
    fun testIdempotentSelectResumeSuspended() {
        var resumed = false
        val delegate = object : Continuation<String> {
            override val context: CoroutineContext get() = EmptyCoroutineContext
            override fun resume(value: String) {
                check(value === "OK")
                resumed = true
            }
            override fun resumeWithException(exception: Throwable) { error("Should not happen") }
        }
        val c = SelectBuilderImpl(delegate)
        check(c.getResult() === COROUTINE_SUSPENDED) // suspend first
        check(!c.isSelected)
        check(c.trySelect("SELECT"))
        check(c.isSelected)
        check(!c.trySelect("OTHER"))
        check(c.trySelect("SELECT"))
        check(!resumed)
        c.completion.resume("OK")
        check(resumed)
        check(c.isSelected)
        check(!c.trySelect("OTHER"))
        check(c.trySelect("SELECT"))
    }

    @Test
    fun testIdempotentSelectResumeWithExceptionInline() {
        var resumed = false
        val delegate = object : Continuation<String> {
            override val context: CoroutineContext get() = EmptyCoroutineContext
            override fun resume(value: String) { error("Should not happen") }
            override fun resumeWithException(exception: Throwable) {
                check(exception is TestException)
                resumed = true
            }
        }
        val c = SelectBuilderImpl(delegate)
        // still running builder
        check(!c.isSelected)
        check(c.trySelect("SELECT"))
        check(c.isSelected)
        check(!c.trySelect("OTHER"))
        check(c.trySelect("SELECT"))
        c.completion.resumeWithException(TestException())
        check(!resumed) // still running builder, didn't invoke delegate
        check(c.isSelected)
        check(!c.trySelect("OTHER"))
        check(c.trySelect("SELECT"))
        try {
            c.getResult() // the builder should throw exception
            error("Failed")
        } catch (e: Throwable) {
            check(e is TestException)
        }
    }

    @Test
    fun testIdempotentSelectResumeWithExceptionSuspended() {
        var resumed = false
        val delegate = object : Continuation<String> {
            override val context: CoroutineContext get() = EmptyCoroutineContext
            override fun resume(value: String) { error("Should not happen") }
            override fun resumeWithException(exception: Throwable) {
                check(exception is TestException)
                resumed = true
            }
        }
        val c = SelectBuilderImpl(delegate)
        check(c.getResult() === COROUTINE_SUSPENDED) // suspend first
        check(!c.isSelected)
        check(c.trySelect("SELECT"))
        check(c.isSelected)
        check(!c.trySelect("OTHER"))
        check(c.trySelect("SELECT"))
        check(!resumed)
        c.completion.resumeWithException(TestException())
        check(resumed)
        check(c.isSelected)
        check(!c.trySelect("OTHER"))
        check(c.trySelect("SELECT"))
    }

    class TestException : Throwable()
}