Handle no native coverage files in NativeCodeCoverageListener.

Test: Unit tests.
Bug: 64915804
Change-Id: Ife78d15cb82600bf51ee14933758886a4b8051a8
(cherry picked from commit 562792280b9d4d917771a620232e0b78bc05631c)

2 files changed, 26 insertions, 1 deletions

diff --git a/src/com/android/tradefed/testtype/NativeCodeCoverageListener.java b/src/com/android/tradefed/testtype/NativeCodeCoverageListener.java
index b1b6c8d10..976c71e54 100644
--- a/src/com/android/tradefed/testtype/NativeCodeCoverageListener.java
+++ b/src/com/android/tradefed/testtype/NativeCodeCoverageListener.java
@@ -28,6 +28,8 @@ import com.android.tradefed.result.ResultForwarder;
 import com.android.tradefed.util.FileUtil;
 import com.android.tradefed.util.ZipUtil;
 
+import com.google.common.base.Splitter;
+
 import java.io.File;
 import java.io.IOException;
 import java.nio.file.Files;
@@ -73,7 +75,7 @@ public final class NativeCodeCoverageListener extends ResultForwarder {
             String findResult = mDevice.executeShellCommand(COVERAGE_FILE_LIST_COMMAND);
 
             Path devicePathRoot = Paths.get(NATIVE_COVERAGE_DEVICE_PATH);
-            for (String deviceFile : findResult.split("\n")) {
+            for (String deviceFile : Splitter.on("\n").omitEmptyStrings().split(findResult)) {
                 // Compute the relative path for the device file.
                 Path relativePath = devicePathRoot.relativize(Paths.get(deviceFile));
                 Path localFullPath = localDir.toPath().resolve(relativePath);
diff --git a/tests/src/com/android/tradefed/testtype/NativeCodeCoverageListenerTest.java b/tests/src/com/android/tradefed/testtype/NativeCodeCoverageListenerTest.java
index dd65aca90..11b225022 100644
--- a/tests/src/com/android/tradefed/testtype/NativeCodeCoverageListenerTest.java
+++ b/tests/src/com/android/tradefed/testtype/NativeCodeCoverageListenerTest.java
@@ -59,6 +59,7 @@ import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.StringJoiner;
+import java.util.zip.ZipFile;
 
 /** Unit tests for {@link NativeCodeCoverageListener}. */
 @RunWith(JUnit4.class)
@@ -135,6 +136,28 @@ public class NativeCodeCoverageListenerTest {
     }
 
     @Test
+    public void testNoCoverageFiles_logsEmptyZip() throws DeviceNotAvailableException, IOException {
+        doReturn(true).when(mMockDevice).enableAdbRoot();
+        doReturn("").when(mMockDevice).executeShellCommand(anyString());
+
+        // Simulate a test run.
+        mCodeCoverageListener.testRunStarted(RUN_NAME, TEST_COUNT);
+        Map<String, String> metric = new HashMap<>();
+        mCodeCoverageListener.testRunEnded(ELAPSED_TIME, TfMetricProtoUtil.upgradeConvert(metric));
+
+        // Verify testLog(..) was called with an empty zip.
+        List<ByteString> logs = mFakeListener.getLogs();
+        assertThat(logs).hasSize(1);
+        File outputZip = folder.newFile("empty_coverage.zip");
+        try (OutputStream out = new FileOutputStream(outputZip)) {
+            logs.get(0).writeTo(out);
+        }
+
+        ZipFile loggedZip = new ZipFile(outputZip);
+        assertThat(loggedZip.size()).isEqualTo(0);
+    }
+
+    @Test
     public void testFailure_unableToPullFile() throws DeviceNotAvailableException {
         // Setup mocks.
         doReturn("/data/misc/trace/some/path/to/coverage.gcda\n")