add tests of HttpDownloader

app/build.gradle

@@ -28,6 +28,8 @@ dependencies {
     }
     compile 'io.reactivex:rxjava:1.1.0'
     compile 'io.reactivex:rxandroid:0.23.0'
+
+    testCompile 'junit:junit:4.12'
 }
 
 if (!hasProperty('sourceDeps')) {

app/src/test/java/org/fdroid/fdroid/net/HttpDownloaderTest.java

@@ -0,0 +1,59 @@
+
+package org.fdroid.fdroid.net;
+
+import org.junit.Test;
+
+import java.io.File;
+import java.io.IOException;
+import java.net.URL;
+
+import static org.junit.Assert.assertTrue;
+
+public class HttpDownloaderTest {
+
+    String[] urls = {
+            "https://www.google.com",
+            "https://en.wikipedia.org/wiki/Index.html",
+            "https://mirrors.kernel.org/debian/dists/stable/Release",
+            "https://f-droid.org/archive/de.we.acaldav_5.apk",
+            // sites that use SNI for HTTPS
+            "https://guardianproject.info/fdroid/repo/index.jar",
+            "https://firstlook.org",
+    };
+
+    private boolean receivedProgress;
+
+    @Test
+    public void downloadUninterruptedTest() throws IOException, InterruptedException {
+        for (String urlString : urls) {
+            URL url = new URL(urlString);
+            File destFile = File.createTempFile("dl-", "");
+            destFile.deleteOnExit(); // this probably does nothing, but maybe...
+            HttpDownloader httpDownloader = new HttpDownloader(url, destFile, null);
+            httpDownloader.download();
+            assertTrue(destFile.exists());
+            assertTrue(destFile.canRead());
+        }
+    }
+
+    @Test
+    public void downloadUninterruptedTestWithProgress() throws IOException, InterruptedException {
+        for (String urlString : urls) {
+            receivedProgress = false;
+            URL url = new URL(urlString);
+            File destFile = File.createTempFile("dl-", "");
+            destFile.deleteOnExit(); // this probably does nothing, but maybe...
+            HttpDownloader httpDownloader = new HttpDownloader(url, destFile, null);
+            httpDownloader.setListener(new Downloader.DownloaderProgressListener() {
+                @Override
+                public void sendProgress(URL sourceUrl, int bytesRead, int totalBytes) {
+                    receivedProgress = true;
+                }
+            });
+            httpDownloader.download();
+            assertTrue(destFile.exists());
+            assertTrue(destFile.canRead());
+            assertTrue(receivedProgress);
+        }
+    }
+}