add FDroidMetricsWorker to gather data into JSON reports

app/src/androidTest/java/org/fdroid/fdroid/work/FDroidMetricsWorkerTest.java

@@ -0,0 +1,72 @@
+/*
+ * Copyright (C) 2021  Hans-Christoph Steiner <hans@eds.org>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 3
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+
+package org.fdroid.fdroid.work;
+
+import androidx.arch.core.executor.testing.InstantTaskExecutorRule;
+import androidx.test.filters.LargeTest;
+import androidx.test.platform.app.InstrumentationRegistry;
+import androidx.work.OneTimeWorkRequest;
+import androidx.work.WorkInfo;
+import com.google.common.util.concurrent.ListenableFuture;
+import org.junit.Ignore;
+import org.junit.Rule;
+import org.junit.Test;
+
+import java.io.IOException;
+import java.util.concurrent.ExecutionException;
+
+import static org.junit.Assert.assertEquals;
+
+/**
+ * This actually runs {@link FDroidMetricsWorker} on a device/emulator and
+ * submits a report to https://metrics.cleaninsights.org
+ * <p>
+ * This is marked with {@link LargeTest} to exclude it from running on GitLab CI
+ * because it always fails on the emulator tests there.  Also, it actually submits
+ * a report.
+ */
+@LargeTest
+public class FDroidMetricsWorkerTest {
+    public static final String TAG = "FDroidMetricsWorkerTest";
+
+    @Rule
+    public InstantTaskExecutorRule instantTaskExecutorRule = new InstantTaskExecutorRule();
+
+    @Rule
+    public WorkManagerTestRule workManagerTestRule = new WorkManagerTestRule();
+
+    /**
+     * A test for easy manual testing.
+     */
+    @Ignore
+    @Test
+    public void testGenerateReport() throws IOException {
+        String json = FDroidMetricsWorker.generateReport(
+                InstrumentationRegistry.getInstrumentation().getTargetContext());
+        System.out.println(json);
+    }
+
+    @Test
+    public void testWorkRequest() throws ExecutionException, InterruptedException {
+        OneTimeWorkRequest request = new OneTimeWorkRequest.Builder(FDroidMetricsWorker.class).build();
+        workManagerTestRule.workManager.enqueue(request).getResult();
+        ListenableFuture<WorkInfo> workInfo = workManagerTestRule.workManager.getWorkInfoById(request.getId());
+        assertEquals(WorkInfo.State.SUCCEEDED, workInfo.get().getState());
+    }
+}