Import of Volley from GitHub to AOSP. am: 212e7004ac am: f77c53c3a3 am: f33c2e45dc am: ba6983e134t_frc_odp_330442040t_frc_odp_330442000t_frc_con_330443020t_frc_cbr_330443000t_frc_ase_330444010t_frc_art_330443060t_frc_adb_330444000frc_340821000frc_340819280frc_340819220frc_340819190frc_340819030frc_340819020frc_340819010frc_340818170frc_340818110android-vts-14.0_r4android-vts-14.0_r3android-vts-14.0_r2android-vts-14.0_r1android-u-beta-1-gplandroid-security-14.0.0_r9android-security-14.0.0_r8android-security-14.0.0_r7android-security-14.0.0_r6android-security-14.0.0_r5android-security-14.0.0_r4android-security-14.0.0_r3android-security-14.0.0_r2android-security-14.0.0_r10android-security-14.0.0_r1android-platform-14.0.0_r9android-platform-14.0.0_r8android-platform-14.0.0_r7android-platform-14.0.0_r6android-platform-14.0.0_r5android-platform-14.0.0_r4android-platform-14.0.0_r3android-platform-14.0.0_r2android-platform-14.0.0_r1android-cts-14.0_r4android-cts-14.0_r3android-cts-14.0_r2android-cts-14.0_r1android-14.0.0_r9android-14.0.0_r8android-14.0.0_r7android-14.0.0_r6android-14.0.0_r54android-14.0.0_r53android-14.0.0_r52android-14.0.0_r51android-14.0.0_r50android-14.0.0_r5android-14.0.0_r45android-14.0.0_r44android-14.0.0_r43android-14.0.0_r42android-14.0.0_r41android-14.0.0_r40android-14.0.0_r4android-14.0.0_r39android-14.0.0_r38android-14.0.0_r37android-14.0.0_r36android-14.0.0_r35android-14.0.0_r34android-14.0.0_r33android-14.0.0_r32android-14.0.0_r31android-14.0.0_r30android-14.0.0_r3android-14.0.0_r29android-14.0.0_r28android-14.0.0_r27android-14.0.0_r26android-14.0.0_r25android-14.0.0_r24android-14.0.0_r23android-14.0.0_r22android-14.0.0_r21android-14.0.0_r20android-14.0.0_r2android-14.0.0_r19android-14.0.0_r18android-14.0.0_r17android-14.0.0_r16android-14.0.0_r15android-14.0.0_r14android-14.0.0_r13android-14.0.0_r12android-14.0.0_r11android-14.0.0_r10android-14.0.0_r1android-13.0.0_r83android-13.0.0_r82android-13.0.0_r81android-13.0.0_r80android-13.0.0_r79android-13.0.0_r78android-13.0.0_r77android-13.0.0_r76android-13.0.0_r75android-13.0.0_r74android-13.0.0_r73android-13.0.0_r72android-13.0.0_r71android-13.0.0_r70android-13.0.0_r69android-13.0.0_r68android-13.0.0_r67android-13.0.0_r66android-13.0.0_r65android-13.0.0_r64android-13.0.0_r63android-13.0.0_r62android-13.0.0_r61android-13.0.0_r60android-13.0.0_r59android-13.0.0_r58android-13.0.0_r57android-13.0.0_r56android-13.0.0_r55android-13.0.0_r54android-13.0.0_r53android-13.0.0_r52android-13.0.0_r51android-13.0.0_r50android-13.0.0_r49android-13.0.0_r48android-13.0.0_r47android-13.0.0_r46android-13.0.0_r45android-13.0.0_r44android-13.0.0_r43android-13.0.0_r42android-13.0.0_r41android-13.0.0_r40android-13.0.0_r39android-13.0.0_r38android-13.0.0_r37android-13.0.0_r36android-13.0.0_r35android-13.0.0_r34android-13.0.0_r33android-13.0.0_r32android-13.0.0_r30android-13.0.0_r29android-13.0.0_r28android-13.0.0_r27android-13.0.0_r24android-13.0.0_r23android-13.0.0_r22android-13.0.0_r21android-13.0.0_r20android-13.0.0_r19android-13.0.0_r18android-13.0.0_r17android-13.0.0_r16aml_uwb_341710010aml_uwb_341513070aml_uwb_341511050aml_uwb_341310300aml_uwb_341310030aml_uwb_341111010aml_uwb_341011000aml_uwb_331910010aml_uwb_331820070aml_uwb_331613010aml_uwb_331611010aml_uwb_331410010aml_uwb_331310030aml_uwb_331115000aml_uwb_331015040aml_uwb_330810010aml_tz5_341510070aml_tz5_341510050aml_tz5_341510010aml_tz4_332714070aml_tz4_332714050aml_tz4_332714010aml_tz4_331910000aml_tz4_331314030aml_tz4_331314020aml_tz4_331314010aml_tz4_331012050aml_tz4_331012040aml_tz4_331012000aml_rkp_341510000aml_rkp_341311000aml_rkp_341114000aml_rkp_341015010aml_rkp_341012000aml_odp_341717000aml_odp_341610000aml_hef_341717050aml_hef_341613000aml_hef_341512030aml_hef_341415040aml_hef_341311010aml_hef_341114030aml_go_wif_330911000aml_go_uwb_330912000aml_go_tz4_330912000aml_go_tet_330914010aml_go_swc_330913000aml_go_sta_330911000aml_go_sdk_330810000aml_go_sch_330911000aml_go_res_330912000aml_go_per_330912000aml_go_odp_330913000aml_go_odp_330912000aml_go_neu_330912000aml_go_net_330913000aml_go_mpr_330912000aml_go_ase_330913000aml_go_ads_330915100aml_go_ads_330915000aml_go_ads_330913000aml_go_adb_330913000aml_cfg_341510000aml_ase_341510000aml_ase_341410000aml_ase_341310010aml_ase_341113000aml_ase_340913000aml_ase_331311020aml_ase_331112000aml_ase_331011020aml_ads_341720000aml_ads_341615050aml_ads_341517040aml_ads_341413000aml_ads_341316030aml_ads_341131050aml_ads_341027030aml_ads_340915050aml_ads_331920180aml_ads_331814200aml_ads_331710270aml_ads_331611190aml_ads_331511020aml_ads_331418080aml_ads_331131000main-16k-with-phonesmain-16kandroid14-tests-releaseandroid14-security-releaseandroid14-s2-releaseandroid14-s1-releaseandroid14-releaseandroid14-qpr3-s2-releaseandroid14-qpr3-releaseandroid14-qpr2-s5-releaseandroid14-qpr2-s4-releaseandroid14-qpr2-s3-releaseandroid14-qpr2-s2-releaseandroid14-qpr2-s1-releaseandroid14-qpr2-releaseandroid14-qpr1-s2-releaseandroid14-qpr1-releaseandroid14-platform-releaseandroid14-mainline-uwb-releaseandroid14-mainline-healthfitness-releaseandroid14-mainline-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Original change: https://android-review.googlesource.com/c/platform/external/volley/+/1758419

Change-Id: I7191d1e2ebb6c416909593386dbbd3481241bf8c

1 files changed, 646 insertions, 0 deletions

diff --git a/core/src/test/java/com/android/volley/toolbox/DiskBasedCacheTest.java b/core/src/test/java/com/android/volley/toolbox/DiskBasedCacheTest.java
new file mode 100644
index 0000000..db6e491
--- /dev/null
+++ b/core/src/test/java/com/android/volley/toolbox/DiskBasedCacheTest.java
@@ -0,0 +1,646 @@
+/*
+ * Copyright (C) 2013 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.volley.toolbox;
+
+import static org.hamcrest.Matchers.arrayWithSize;
+import static org.hamcrest.Matchers.emptyArray;
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.is;
+import static org.hamcrest.Matchers.nullValue;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertThat;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.anyInt;
+import static org.mockito.Mockito.atLeastOnce;
+import static org.mockito.Mockito.doReturn;
+import static org.mockito.Mockito.doThrow;
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.verify;
+
+import com.android.volley.Cache;
+import com.android.volley.Header;
+import com.android.volley.toolbox.DiskBasedCache.CacheHeader;
+import com.android.volley.toolbox.DiskBasedCache.CountingInputStream;
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.EOFException;
+import java.io.File;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Random;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.ExpectedException;
+import org.junit.rules.TemporaryFolder;
+import org.junit.runner.RunWith;
+import org.robolectric.RobolectricTestRunner;
+import org.robolectric.annotation.Config;
+
+@RunWith(RobolectricTestRunner.class)
+@Config(sdk = 16)
+public class DiskBasedCacheTest {
+
+    private static final int MAX_SIZE = 1024 * 1024;
+
+    private Cache cache;
+
+    @Rule public TemporaryFolder temporaryFolder = new TemporaryFolder();
+
+    @Rule public ExpectedException exception = ExpectedException.none();
+
+    @Before
+    public void setup() throws IOException {
+        // Initialize empty cache
+        cache = new DiskBasedCache(temporaryFolder.getRoot(), MAX_SIZE);
+        cache.initialize();
+    }
+
+    @After
+    public void teardown() {
+        cache = null;
+    }
+
+    @Test
+    public void testEmptyInitialize() {
+        assertThat(cache.get("key"), is(nullValue()));
+    }
+
+    @Test
+    public void testPutGetZeroBytes() {
+        Cache.Entry entry = new Cache.Entry();
+        entry.data = new byte[0];
+        entry.serverDate = 1234567L;
+        entry.lastModified = 13572468L;
+        entry.ttl = 9876543L;
+        entry.softTtl = 8765432L;
+        entry.etag = "etag";
+        entry.responseHeaders = new HashMap<>();
+        entry.responseHeaders.put("fruit", "banana");
+        entry.responseHeaders.put("color", "yellow");
+        cache.put("my-magical-key", entry);
+
+        assertThatEntriesAreEqual(cache.get("my-magical-key"), entry);
+        assertThat(cache.get("unknown-key"), is(nullValue()));
+    }
+
+    @Test
+    public void testPutRemoveGet() {
+        Cache.Entry entry = randomData(511);
+        cache.put("key", entry);
+
+        assertThatEntriesAreEqual(cache.get("key"), entry);
+
+        cache.remove("key");
+        assertThat(cache.get("key"), is(nullValue()));
+        assertThat(listCachedFiles(), is(emptyArray()));
+    }
+
+    @Test
+    public void testPutClearGet() {
+        Cache.Entry entry = randomData(511);
+        cache.put("key", entry);
+
+        assertThatEntriesAreEqual(cache.get("key"), entry);
+
+        cache.clear();
+        assertThat(cache.get("key"), is(nullValue()));
+        assertThat(listCachedFiles(), is(emptyArray()));
+    }
+
+    @Test
+    public void testReinitialize() {
+        Cache.Entry entry = randomData(1023);
+        cache.put("key", entry);
+
+        Cache copy = new DiskBasedCache(temporaryFolder.getRoot(), MAX_SIZE);
+        copy.initialize();
+
+        assertThatEntriesAreEqual(copy.get("key"), entry);
+    }
+
+    @Test
+    public void testInvalidate() {
+        Cache.Entry entry = randomData(32);
+        entry.softTtl = 8765432L;
+        entry.ttl = 9876543L;
+        cache.put("key", entry);
+
+        cache.invalidate("key", false);
+        entry.softTtl = 0; // expired
+        assertThatEntriesAreEqual(cache.get("key"), entry);
+    }
+
+    @Test
+    public void testInvalidateFullExpire() {
+        Cache.Entry entry = randomData(32);
+        entry.softTtl = 8765432L;
+        entry.ttl = 9876543L;
+        cache.put("key", entry);
+
+        cache.invalidate("key", true);
+        entry.softTtl = 0; // expired
+        entry.ttl = 0; // expired
+        assertThatEntriesAreEqual(cache.get("key"), entry);
+    }
+
+    @Test
+    public void testTooLargeEntry() {
+        Cache.Entry entry = randomData(MAX_SIZE - getEntrySizeOnDisk("oversize"));
+        cache.put("oversize", entry);
+
+        assertThat(cache.get("oversize"), is(nullValue()));
+    }
+
+    @Test
+    public void testMaxSizeEntry() {
+        Cache.Entry entry = randomData(MAX_SIZE - getEntrySizeOnDisk("maxsize") - 1);
+        cache.put("maxsize", entry);
+
+        assertThatEntriesAreEqual(cache.get("maxsize"), entry);
+    }
+
+    @Test
+    public void testTrimAtThreshold() {
+        // Start with the largest possible entry.
+        Cache.Entry entry = randomData(MAX_SIZE - getEntrySizeOnDisk("maxsize") - 1);
+        cache.put("maxsize", entry);
+
+        assertThatEntriesAreEqual(cache.get("maxsize"), entry);
+
+        // Now any new entry should cause the first one to be cleared.
+        entry = randomData(0);
+        cache.put("bit", entry);
+
+        assertThat(cache.get("goodsize"), is(nullValue()));
+        assertThatEntriesAreEqual(cache.get("bit"), entry);
+    }
+
+    @Test
+    public void testTrimWithMultipleEvictions_underHysteresisThreshold() {
+        Cache.Entry entry1 = randomData(MAX_SIZE / 3 - getEntrySizeOnDisk("entry1") - 1);
+        cache.put("entry1", entry1);
+        Cache.Entry entry2 = randomData(MAX_SIZE / 3 - getEntrySizeOnDisk("entry2") - 1);
+        cache.put("entry2", entry2);
+        Cache.Entry entry3 = randomData(MAX_SIZE / 3 - getEntrySizeOnDisk("entry3") - 1);
+        cache.put("entry3", entry3);
+
+        assertThatEntriesAreEqual(cache.get("entry1"), entry1);
+        assertThatEntriesAreEqual(cache.get("entry2"), entry2);
+        assertThatEntriesAreEqual(cache.get("entry3"), entry3);
+
+        Cache.Entry entry =
+                randomData(
+                        (int) (DiskBasedCache.HYSTERESIS_FACTOR * MAX_SIZE)
+                                - getEntrySizeOnDisk("max"));
+        cache.put("max", entry);
+
+        assertThat(cache.get("entry1"), is(nullValue()));
+        assertThat(cache.get("entry2"), is(nullValue()));
+        assertThat(cache.get("entry3"), is(nullValue()));
+        assertThatEntriesAreEqual(cache.get("max"), entry);
+    }
+
+    @Test
+    public void testTrimWithMultipleEvictions_atHysteresisThreshold() {
+        Cache.Entry entry1 = randomData(MAX_SIZE / 3 - getEntrySizeOnDisk("entry1") - 1);
+        cache.put("entry1", entry1);
+        Cache.Entry entry2 = randomData(MAX_SIZE / 3 - getEntrySizeOnDisk("entry2") - 1);
+        cache.put("entry2", entry2);
+        Cache.Entry entry3 = randomData(MAX_SIZE / 3 - getEntrySizeOnDisk("entry3") - 1);
+        cache.put("entry3", entry3);
+
+        assertThatEntriesAreEqual(cache.get("entry1"), entry1);
+        assertThatEntriesAreEqual(cache.get("entry2"), entry2);
+        assertThatEntriesAreEqual(cache.get("entry3"), entry3);
+
+        Cache.Entry entry =
+                randomData(
+                        (int) (DiskBasedCache.HYSTERESIS_FACTOR * MAX_SIZE)
+                                - getEntrySizeOnDisk("max")
+                                + 1);
+        cache.put("max", entry);
+
+        assertThat(cache.get("entry1"), is(nullValue()));
+        assertThat(cache.get("entry2"), is(nullValue()));
+        assertThat(cache.get("entry3"), is(nullValue()));
+        assertThat(cache.get("max"), is(nullValue()));
+    }
+
+    @Test
+    public void testTrimWithPartialEvictions() {
+        Cache.Entry entry1 = randomData(MAX_SIZE / 3 - getEntrySizeOnDisk("entry1") - 1);
+        cache.put("entry1", entry1);
+        Cache.Entry entry2 = randomData(MAX_SIZE / 3 - getEntrySizeOnDisk("entry2") - 1);
+        cache.put("entry2", entry2);
+        Cache.Entry entry3 = randomData(MAX_SIZE / 3 - getEntrySizeOnDisk("entry3") - 1);
+        cache.put("entry3", entry3);
+
+        assertThatEntriesAreEqual(cache.get("entry1"), entry1);
+        assertThatEntriesAreEqual(cache.get("entry2"), entry2);
+        assertThatEntriesAreEqual(cache.get("entry3"), entry3);
+
+        Cache.Entry entry4 = randomData((MAX_SIZE - getEntrySizeOnDisk("entry4") - 1) / 2);
+        cache.put("entry4", entry4);
+
+        assertThat(cache.get("entry1"), is(nullValue()));
+        assertThat(cache.get("entry2"), is(nullValue()));
+        assertThatEntriesAreEqual(cache.get("entry3"), entry3);
+        assertThatEntriesAreEqual(cache.get("entry4"), entry4);
+    }
+
+    @Test
+    public void testLargeEntryDoesntClearCache() {
+        // Writing a large entry to an empty cache should succeed
+        Cache.Entry largeEntry = randomData(MAX_SIZE - getEntrySizeOnDisk("largeEntry") - 1);
+        cache.put("largeEntry", largeEntry);
+
+        assertThatEntriesAreEqual(cache.get("largeEntry"), largeEntry);
+
+        // Reset and fill up ~half the cache.
+        cache.clear();
+        Cache.Entry entry = randomData(MAX_SIZE / 2 - getEntrySizeOnDisk("entry") - 1);
+        cache.put("entry", entry);
+
+        assertThatEntriesAreEqual(cache.get("entry"), entry);
+
+        // Writing the large entry should no-op, because otherwise the pruning algorithm would clear
+        // the whole cache, since the large entry is above the hysteresis threshold.
+        cache.put("largeEntry", largeEntry);
+
+        assertThat(cache.get("largeEntry"), is(nullValue()));
+        assertThatEntriesAreEqual(cache.get("entry"), entry);
+    }
+
+    @Test
+    @SuppressWarnings("TryFinallyCanBeTryWithResources")
+    public void testGetBadMagic() throws IOException {
+        // Cache something
+        Cache.Entry entry = randomData(1023);
+        cache.put("key", entry);
+        assertThatEntriesAreEqual(cache.get("key"), entry);
+
+        // Overwrite the magic header
+        File cacheFolder = temporaryFolder.getRoot();
+        File file = cacheFolder.listFiles()[0];
+        FileOutputStream fos = new FileOutputStream(file);
+        try {
+            DiskBasedCache.writeInt(fos, 0); // overwrite magic
+        } finally {
+            //noinspection ThrowFromFinallyBlock
+            fos.close();
+        }
+
+        assertThat(cache.get("key"), is(nullValue()));
+        assertThat(listCachedFiles(), is(emptyArray()));
+    }
+
+    @Test
+    @SuppressWarnings("TryFinallyCanBeTryWithResources")
+    public void testGetWrongKey() throws IOException {
+        // Cache something
+        Cache.Entry entry = randomData(1023);
+        cache.put("key", entry);
+        assertThatEntriesAreEqual(cache.get("key"), entry);
+
+        // Access the cached file
+        File cacheFolder = temporaryFolder.getRoot();
+        File file = cacheFolder.listFiles()[0];
+        FileOutputStream fos = new FileOutputStream(file);
+        try {
+            // Overwrite with a different key
+            CacheHeader wrongHeader = new CacheHeader("bad", entry);
+            wrongHeader.writeHeader(fos);
+        } finally {
+            //noinspection ThrowFromFinallyBlock
+            fos.close();
+        }
+
+        // key is gone, but file is still there
+        assertThat(cache.get("key"), is(nullValue()));
+        assertThat(listCachedFiles(), is(arrayWithSize(1)));
+
+        // Note: file is now a zombie because its key does not map to its name
+    }
+
+    @Test
+    public void testStreamToBytesNegativeLength() throws IOException {
+        byte[] data = new byte[1];
+        CountingInputStream cis =
+                new CountingInputStream(new ByteArrayInputStream(data), data.length);
+        exception.expect(IOException.class);
+        DiskBasedCache.streamToBytes(cis, -1);
+    }
+
+    @Test
+    public void testStreamToBytesExcessiveLength() throws IOException {
+        byte[] data = new byte[1];
+        CountingInputStream cis =
+                new CountingInputStream(new ByteArrayInputStream(data), data.length);
+        exception.expect(IOException.class);
+        DiskBasedCache.streamToBytes(cis, 2);
+    }
+
+    @Test
+    public void testStreamToBytesOverflow() throws IOException {
+        byte[] data = new byte[0];
+        CountingInputStream cis =
+                new CountingInputStream(new ByteArrayInputStream(data), 0x100000000L);
+        exception.expect(IOException.class);
+        DiskBasedCache.streamToBytes(cis, 0x100000000L); // int value is 0
+    }
+
+    @Test
+    public void testReadHeaderListWithNegativeSize() throws IOException {
+        // If a cached header list is corrupted and begins with a negative size,
+        // verify that readHeaderList will throw an IOException.
+        ByteArrayOutputStream baos = new ByteArrayOutputStream();
+        DiskBasedCache.writeInt(baos, -1); // negative size
+        CountingInputStream cis =
+                new CountingInputStream(
+                        new ByteArrayInputStream(baos.toByteArray()), Integer.MAX_VALUE);
+        // Expect IOException due to negative size
+        exception.expect(IOException.class);
+        DiskBasedCache.readHeaderList(cis);
+    }
+
+    @Test
+    public void testReadHeaderListWithGinormousSize() throws IOException {
+        // If a cached header list is corrupted and begins with 2GB size, verify
+        // that readHeaderList will throw EOFException rather than OutOfMemoryError.
+        ByteArrayOutputStream baos = new ByteArrayOutputStream();
+        DiskBasedCache.writeInt(baos, Integer.MAX_VALUE); // 2GB size
+        CountingInputStream cis =
+                new CountingInputStream(new ByteArrayInputStream(baos.toByteArray()), baos.size());
+        // Expect EOFException when end of stream is reached
+        exception.expect(EOFException.class);
+        DiskBasedCache.readHeaderList(cis);
+    }
+
+    @Test
+    public void testFileIsDeletedWhenWriteHeaderFails() throws IOException {
+        // Create DataOutputStream that throws IOException
+        OutputStream mockedOutputStream = spy(OutputStream.class);
+        doThrow(IOException.class).when(mockedOutputStream).write(anyInt());
+
+        // Create read-only copy that fails to write anything
+        DiskBasedCache readonly = spy((DiskBasedCache) cache);
+        doReturn(mockedOutputStream).when(readonly).createOutputStream(any(File.class));
+
+        // Attempt to write
+        readonly.put("key", randomData(1111));
+
+        // write is called at least once because each linked stream flushes when closed
+        verify(mockedOutputStream, atLeastOnce()).write(anyInt());
+        assertThat(readonly.get("key"), is(nullValue()));
+        assertThat(listCachedFiles(), is(emptyArray()));
+
+        // Note: original cache will try (without success) to read from file
+        assertThat(cache.get("key"), is(nullValue()));
+    }
+
+    @Test
+    public void testIOExceptionInInitialize() throws IOException {
+        // Cache a few kilobytes
+        cache.put("kilobyte", randomData(1024));
+        cache.put("kilobyte2", randomData(1024));
+        cache.put("kilobyte3", randomData(1024));
+
+        // Create DataInputStream that throws IOException
+        InputStream mockedInputStream = spy(InputStream.class);
+        //noinspection ResultOfMethodCallIgnored
+        doThrow(IOException.class).when(mockedInputStream).read();
+
+        // Create broken cache that fails to read anything
+        DiskBasedCache broken = spy(new DiskBasedCache(temporaryFolder.getRoot()));
+        doReturn(mockedInputStream).when(broken).createInputStream(any(File.class));
+
+        // Attempt to initialize
+        broken.initialize();
+
+        // Everything is gone
+        assertThat(broken.get("kilobyte"), is(nullValue()));
+        assertThat(broken.get("kilobyte2"), is(nullValue()));
+        assertThat(broken.get("kilobyte3"), is(nullValue()));
+        assertThat(listCachedFiles(), is(emptyArray()));
+
+        // Verify that original cache can cope with missing files
+        assertThat(cache.get("kilobyte"), is(nullValue()));
+        assertThat(cache.get("kilobyte2"), is(nullValue()));
+        assertThat(cache.get("kilobyte3"), is(nullValue()));
+    }
+
+    @Test
+    public void testManyResponseHeaders() {
+        Cache.Entry entry = new Cache.Entry();
+        entry.data = new byte[0];
+        entry.responseHeaders = new HashMap<>();
+        for (int i = 0; i < 0xFFFF; i++) {
+            entry.responseHeaders.put(Integer.toString(i), "");
+        }
+        cache.put("key", entry);
+    }
+
+    @Test
+    @SuppressWarnings("TryFinallyCanBeTryWithResources")
+    public void testCountingInputStreamByteCount() throws IOException {
+        // Write some bytes
+        ByteArrayOutputStream out = new ByteArrayOutputStream();
+        //noinspection ThrowFromFinallyBlock
+        try {
+            DiskBasedCache.writeInt(out, 1);
+            DiskBasedCache.writeLong(out, -1L);
+            DiskBasedCache.writeString(out, "hamburger");
+        } finally {
+            //noinspection ThrowFromFinallyBlock
+            out.close();
+        }
+        long bytesWritten = out.size();
+
+        // Read the bytes and compare the counts
+        CountingInputStream cis =
+                new CountingInputStream(new ByteArrayInputStream(out.toByteArray()), bytesWritten);
+        try {
+            assertThat(cis.bytesRemaining(), is(bytesWritten));
+            assertThat(cis.bytesRead(), is(0L));
+            assertThat(DiskBasedCache.readInt(cis), is(1));
+            assertThat(DiskBasedCache.readLong(cis), is(-1L));
+            assertThat(DiskBasedCache.readString(cis), is("hamburger"));
+            assertThat(cis.bytesRead(), is(bytesWritten));
+            assertThat(cis.bytesRemaining(), is(0L));
+        } finally {
+            //noinspection ThrowFromFinallyBlock
+            cis.close();
+        }
+    }
+
+    /* Serialization tests */
+
+    @Test
+    public void testEmptyReadThrowsEOF() throws IOException {
+        ByteArrayInputStream empty = new ByteArrayInputStream(new byte[] {});
+        exception.expect(EOFException.class);
+        DiskBasedCache.readInt(empty);
+    }
+
+    @Test
+    public void serializeInt() throws IOException {
+        ByteArrayOutputStream baos = new ByteArrayOutputStream();
+        DiskBasedCache.writeInt(baos, 0);
+        DiskBasedCache.writeInt(baos, 19791214);
+        DiskBasedCache.writeInt(baos, -20050711);
+        DiskBasedCache.writeInt(baos, Integer.MIN_VALUE);
+        DiskBasedCache.writeInt(baos, Integer.MAX_VALUE);
+        ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
+        assertEquals(DiskBasedCache.readInt(bais), 0);
+        assertEquals(DiskBasedCache.readInt(bais), 19791214);
+        assertEquals(DiskBasedCache.readInt(bais), -20050711);
+        assertEquals(DiskBasedCache.readInt(bais), Integer.MIN_VALUE);
+        assertEquals(DiskBasedCache.readInt(bais), Integer.MAX_VALUE);
+    }
+
+    @Test
+    public void serializeLong() throws Exception {
+        ByteArrayOutputStream baos = new ByteArrayOutputStream();
+        DiskBasedCache.writeLong(baos, 0);
+        DiskBasedCache.writeLong(baos, 31337);
+        DiskBasedCache.writeLong(baos, -4160);
+        DiskBasedCache.writeLong(baos, 4295032832L);
+        DiskBasedCache.writeLong(baos, -4314824046L);
+        DiskBasedCache.writeLong(baos, Long.MIN_VALUE);
+        DiskBasedCache.writeLong(baos, Long.MAX_VALUE);
+        ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
+        assertEquals(DiskBasedCache.readLong(bais), 0);
+        assertEquals(DiskBasedCache.readLong(bais), 31337);
+        assertEquals(DiskBasedCache.readLong(bais), -4160);
+        assertEquals(DiskBasedCache.readLong(bais), 4295032832L);
+        assertEquals(DiskBasedCache.readLong(bais), -4314824046L);
+        assertEquals(DiskBasedCache.readLong(bais), Long.MIN_VALUE);
+        assertEquals(DiskBasedCache.readLong(bais), Long.MAX_VALUE);
+    }
+
+    @Test
+    public void serializeString() throws Exception {
+        ByteArrayOutputStream baos = new ByteArrayOutputStream();
+        DiskBasedCache.writeString(baos, "");
+        DiskBasedCache.writeString(baos, "This is a string.");
+        DiskBasedCache.writeString(baos, "ファイカス");
+        CountingInputStream cis =
+                new CountingInputStream(new ByteArrayInputStream(baos.toByteArray()), baos.size());
+        assertEquals(DiskBasedCache.readString(cis), "");
+        assertEquals(DiskBasedCache.readString(cis), "This is a string.");
+        assertEquals(DiskBasedCache.readString(cis), "ファイカス");
+    }
+
+    @Test
+    public void serializeHeaders() throws Exception {
+        ByteArrayOutputStream baos = new ByteArrayOutputStream();
+        List<Header> empty = new ArrayList<>();
+        DiskBasedCache.writeHeaderList(empty, baos);
+        DiskBasedCache.writeHeaderList(null, baos);
+        List<Header> twoThings = new ArrayList<>();
+        twoThings.add(new Header("first", "thing"));
+        twoThings.add(new Header("second", "item"));
+        DiskBasedCache.writeHeaderList(twoThings, baos);
+        List<Header> emptyKey = new ArrayList<>();
+        emptyKey.add(new Header("", "value"));
+        DiskBasedCache.writeHeaderList(emptyKey, baos);
+        List<Header> emptyValue = new ArrayList<>();
+        emptyValue.add(new Header("key", ""));
+        DiskBasedCache.writeHeaderList(emptyValue, baos);
+        List<Header> sameKeys = new ArrayList<>();
+        sameKeys.add(new Header("key", "value"));
+        sameKeys.add(new Header("key", "value2"));
+        DiskBasedCache.writeHeaderList(sameKeys, baos);
+        CountingInputStream cis =
+                new CountingInputStream(new ByteArrayInputStream(baos.toByteArray()), baos.size());
+        assertEquals(DiskBasedCache.readHeaderList(cis), empty);
+        assertEquals(DiskBasedCache.readHeaderList(cis), empty); // null reads back empty
+        assertEquals(DiskBasedCache.readHeaderList(cis), twoThings);
+        assertEquals(DiskBasedCache.readHeaderList(cis), emptyKey);
+        assertEquals(DiskBasedCache.readHeaderList(cis), emptyValue);
+        assertEquals(DiskBasedCache.readHeaderList(cis), sameKeys);
+    }
+
+    @Test
+    public void publicMethods() throws Exception {
+        // Catch-all test to find API-breaking changes.
+        assertNotNull(DiskBasedCache.class.getConstructor(File.class, int.class));
+        assertNotNull(
+                DiskBasedCache.class.getConstructor(DiskBasedCache.FileSupplier.class, int.class));
+        assertNotNull(DiskBasedCache.class.getConstructor(File.class));
+        assertNotNull(DiskBasedCache.class.getConstructor(DiskBasedCache.FileSupplier.class));
+
+        assertNotNull(DiskBasedCache.class.getMethod("getFileForKey", String.class));
+    }
+
+    @Test
+    public void initializeIfRootDirectoryDeleted() {
+        temporaryFolder.delete();
+
+        Cache.Entry entry = randomData(101);
+        cache.put("key1", entry);
+
+        assertThat(cache.get("key1"), is(nullValue()));
+
+        // confirm that we can now store entries
+        cache.put("key2", entry);
+        assertThatEntriesAreEqual(cache.get("key2"), entry);
+    }
+
+    /* Test helpers */
+
+    private void assertThatEntriesAreEqual(Cache.Entry actual, Cache.Entry expected) {
+        assertThat(actual.data, is(equalTo(expected.data)));
+        assertThat(actual.etag, is(equalTo(expected.etag)));
+        assertThat(actual.lastModified, is(equalTo(expected.lastModified)));
+        assertThat(actual.responseHeaders, is(equalTo(expected.responseHeaders)));
+        assertThat(actual.serverDate, is(equalTo(expected.serverDate)));
+        assertThat(actual.softTtl, is(equalTo(expected.softTtl)));
+        assertThat(actual.ttl, is(equalTo(expected.ttl)));
+    }
+
+    private Cache.Entry randomData(int length) {
+        Cache.Entry entry = new Cache.Entry();
+        byte[] data = new byte[length];
+        new Random(42).nextBytes(data); // explicit seed for reproducible results
+        entry.data = data;
+        return entry;
+    }
+
+    private File[] listCachedFiles() {
+        return temporaryFolder.getRoot().listFiles();
+    }
+
+    private int getEntrySizeOnDisk(String key) {
+        // Header size is:
+        // 4 bytes for magic int
+        // 8 + len(key) bytes for key (long length)
+        // 8 bytes for etag (long length + 0 characters)
+        // 32 bytes for serverDate, lastModified, ttl, and softTtl longs
+        // 4 bytes for length of header list int
+        // == 56 + len(key) bytes total.
+        return 56 + key.length();
+    }
+}