| /* |
| * Copyright 2022 Google LLC |
| * |
| * 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.google.android.libraries.mobiledatadownload.file.common.internal; |
| |
| import static com.google.android.libraries.mobiledatadownload.file.common.testing.StreamUtils.readFileFromSource; |
| import static com.google.common.truth.Truth.assertThat; |
| import static java.nio.charset.StandardCharsets.UTF_8; |
| import static org.junit.Assert.assertThrows; |
| |
| import com.google.thirdparty.robolectric.GoogleRobolectricTestRunner; |
| import java.io.IOException; |
| import java.io.InputStream; |
| import java.util.concurrent.Callable; |
| import org.junit.Test; |
| import org.junit.runner.RunWith; |
| |
| @RunWith(GoogleRobolectricTestRunner.class) |
| public final class LazyByteArrayInputStreamTest { |
| |
| private static final String CONTENT = "The five boxing wizards jump quickly"; |
| private static final Callable<byte[]> CONTENT_CALLABLE = () -> CONTENT.getBytes(UTF_8); |
| |
| @Test |
| public void callableIsCalledLazilyExactlyOnce() throws IOException { |
| SpyCallable<byte[]> spy = new SpyCallable<byte[]>(CONTENT_CALLABLE); |
| InputStream stream = new LazyByteArrayInputStream(spy); |
| |
| assertThat(spy.callCount()).isEqualTo(0); |
| stream.read(); |
| stream.read(); |
| assertThat(spy.callCount()).isEqualTo(1); |
| } |
| |
| @Test |
| public void exceptionFromCallableIsWrappedAndPropagated() throws IOException { |
| Callable<byte[]> genericThrower = |
| () -> { |
| throw new Exception("generic"); |
| }; |
| InputStream genericStream = new LazyByteArrayInputStream(genericThrower); |
| IOException genericThrown = assertThrows(IOException.class, () -> genericStream.read()); |
| assertThat(genericThrown).hasCauseThat().hasMessageThat().isEqualTo("generic"); |
| |
| Callable<byte[]> ioCallable = |
| () -> { |
| throw new IOException("io"); |
| }; |
| InputStream ioStream = new LazyByteArrayInputStream(ioCallable); |
| IOException ioThrown = assertThrows(IOException.class, () -> ioStream.read()); |
| assertThat(ioThrown).hasMessageThat().isEqualTo("io"); |
| } |
| |
| @Test |
| public void available_onStreamThatHasNotBeenRead_returnsZero() throws IOException { |
| SpyCallable<byte[]> spy = new SpyCallable<byte[]>(CONTENT_CALLABLE); |
| InputStream stream = new LazyByteArrayInputStream(spy); |
| |
| assertThat(stream.available()).isEqualTo(0); |
| assertThat(spy.callCount()).isEqualTo(0); |
| } |
| |
| @Test |
| public void available_returnsRemainingCallableBytes() throws IOException { |
| InputStream stream = new LazyByteArrayInputStream(CONTENT_CALLABLE); |
| |
| stream.skip(3); |
| assertThat(stream.available()).isEqualTo(CONTENT.length() - 3); |
| } |
| |
| @Test |
| public void close_callsCallable() throws IOException { |
| SpyCallable<byte[]> spy = new SpyCallable<byte[]>(CONTENT_CALLABLE); |
| InputStream stream = new LazyByteArrayInputStream(spy); |
| |
| stream.close(); |
| assertThat(spy.callCount()).isEqualTo(1); |
| } |
| |
| @Test |
| public void read_returnsCallableBytes() throws IOException { |
| InputStream stream = new LazyByteArrayInputStream(CONTENT_CALLABLE); |
| assertThat(readFileFromSource(stream)).isEqualTo(CONTENT); |
| } |
| |
| @Test |
| public void skip_skipsCallableBytes() throws IOException { |
| InputStream stream = new LazyByteArrayInputStream(CONTENT_CALLABLE); |
| stream.skip(5); |
| assertThat(readFileFromSource(stream)).isEqualTo(CONTENT.substring(5)); |
| } |
| |
| @Test |
| public void markSupported_returnsTrue() throws IOException { |
| InputStream stream = new LazyByteArrayInputStream(CONTENT_CALLABLE); |
| assertThat(stream.markSupported()).isTrue(); |
| } |
| |
| @Test |
| public void reset_fromFirstByte() throws IOException { |
| // Read whole string, reset to default mark position = 0, read same thing |
| InputStream stream = new LazyByteArrayInputStream(CONTENT_CALLABLE); |
| |
| readFileFromSource(stream); |
| stream.reset(); |
| assertThat(readFileFromSource(stream)).isEqualTo(CONTENT); |
| } |
| |
| @Test |
| public void markAndReset_fromMidwayByte() throws IOException { |
| // Skip 10 and mark, read remainder, reset to marked 10 position, read same thing |
| InputStream stream = new LazyByteArrayInputStream(CONTENT_CALLABLE); |
| |
| stream.skip(10); |
| stream.mark(0); // arbitrary readlimit |
| |
| readFileFromSource(stream); |
| stream.reset(); |
| assertThat(readFileFromSource(stream)).isEqualTo(CONTENT.substring(10)); |
| } |
| |
| /** A substitute for Mockito.spy(Callable<T>) since Mockito can't wrap anonymous classes. */ |
| private static final class SpyCallable<T> implements Callable<T> { |
| private final Callable<T> delegate; |
| private int callCount; |
| |
| SpyCallable(Callable<T> delegate) { |
| this.delegate = delegate; |
| this.callCount = 0; |
| } |
| |
| @Override |
| public T call() throws Exception { |
| callCount++; |
| return delegate.call(); |
| } |
| |
| int callCount() { |
| return callCount; |
| } |
| } |
| } |