add CleanCacheWorker Robolectric tests

app/src/test/java/org/fdroid/fdroid/TestUtils.java

@@ -8,6 +8,7 @@ import android.content.ContextWrapper;
 import android.content.pm.ProviderInfo;
 import android.net.Uri;
 import androidx.test.core.app.ApplicationProvider;
+import org.apache.commons.io.IOUtils;
 import org.fdroid.fdroid.data.Apk;
 import org.fdroid.fdroid.data.ApkProvider;
 import org.fdroid.fdroid.data.App;
@@ -190,4 +191,17 @@ public class TestUtils {
         modifiersField.setInt(field, field.getModifiers() & ~Modifier.FINAL);
         field.set(null, newValue);
     }
+
+    public static void ls(File dir) {
+        Process p = null;
+        try {
+            p = Runtime.getRuntime().exec("ls -l " + dir.getAbsolutePath());
+            p.waitFor();
+            for (String line : IOUtils.readLines(p.getInputStream())) {
+                System.out.println(line);
+            }
+        } catch (IOException | InterruptedException e) {
+            e.printStackTrace();
+        }
+    }
 }

app/src/test/java/org/fdroid/fdroid/work/CleanCacheWorkerTest.java

@@ -0,0 +1,93 @@
+package org.fdroid.fdroid.work;
+
+import android.content.Context;
+import androidx.test.core.app.ApplicationProvider;
+import org.fdroid.fdroid.BuildConfig;
+import org.fdroid.fdroid.Preferences;
+import org.fdroid.fdroid.nearby.LocalRepoManager;
+import org.fdroid.fdroid.shadows.ShadowLog;
+import org.junit.Assume;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.robolectric.RobolectricTestRunner;
+
+import java.io.File;
+import java.io.IOException;
+import java.util.ArrayList;
+
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+/**
+ * Test non-time-based cache deletion methods.  Robolectric is lacking full
+ * support for getting time from files, so methods that rely on time must be
+ * tested in {@code CleanCacheWorkerTest} in {@code androidTest}.
+ */
+@RunWith(RobolectricTestRunner.class)
+public class CleanCacheWorkerTest {
+    public static final String TAG = "CleanCacheWorkerTest";
+
+    private static final Context CONTEXT = ApplicationProvider.getApplicationContext();
+    private static final File FILES_DIR = CONTEXT.getFilesDir();
+
+    @Before
+    public void setUp() {
+        ShadowLog.stream = System.out;
+        Preferences.setupForTests(CONTEXT);
+    }
+
+    @Test
+    public void testDeleteOldInstallerFiles() throws IOException {
+        Assume.assumeTrue(BuildConfig.FLAVOR.startsWith("full"));
+        ArrayList<File> webRootAssetFiles = new ArrayList<>();
+        File indexHtml = new File(FILES_DIR, "index.html");
+        assertTrue(indexHtml.createNewFile());
+        webRootAssetFiles.add(indexHtml);
+        for (String name : LocalRepoManager.WEB_ROOT_ASSET_FILES) {
+            File f = new File(FILES_DIR, name);
+            assertTrue(f.createNewFile());
+            webRootAssetFiles.add(f);
+        }
+        File apk = new File(FILES_DIR, "fake.apk");
+        assertTrue(apk.createNewFile());
+        File giantblob = new File(FILES_DIR, "giantblob");
+        assertTrue(giantblob.createNewFile());
+        File obf = new File(FILES_DIR, "fake.obf");
+        assertTrue(obf.createNewFile());
+        File zip = new File(FILES_DIR, "fake.zip");
+        assertTrue(zip.createNewFile());
+        CleanCacheWorker.deleteOldInstallerFiles(CONTEXT);
+        assertFalse(apk.exists());
+        assertFalse(giantblob.exists());
+        assertFalse(obf.exists());
+        assertFalse(zip.exists());
+        for (File f : webRootAssetFiles) {
+            assertTrue(f.exists());
+        }
+    }
+
+    /**
+     * Pure smoke check, Robolectric does not support file times fully.
+     */
+    @Test
+    public void testDeleteExpiredApksFromCache() {
+        CleanCacheWorker.deleteExpiredApksFromCache(CONTEXT);
+    }
+
+    /**
+     * Pure smoke check, Robolectric does not support file times fully.
+     */
+    @Test
+    public void testDeleteStrayIndexFiles() {
+        CleanCacheWorker.deleteStrayIndexFiles(CONTEXT);
+    }
+
+    /**
+     * Pure smoke check, Robolectric does not support file times fully.
+     */
+    @Test
+    public void testDeleteOldIcons() {
+        CleanCacheWorker.deleteOldIcons(CONTEXT);
+    }
+}