Fix flaky unit test (#6984)

This test is flaky because there is a race condition. If the extra thread calls the read method before the test writes the second string, then the read method will not wait for new bytes and will return -1 because the download state is COMPLETED. The test only passes when the timing works out such that the write happens before the extra thread calls the read method. Now, the test sets the download state to IN_PROGRESS, so the read method will correctly wait for new bytes if it is called before the write happens.

Author: jrnorth

catalog/core/catalog-core-standardframework/src/test/java/ddf/catalog/resource/download/ReliableResourceInputStreamTest.java

@@ -149,11 +149,13 @@ public void testReadByteBufferFbosBytesWritten() throws Exception {
 
   @Test
   public void testReadByteBufferBlocksUntilNewFbosBytesWritten() throws Exception {
+    when(downloadState.getDownloadState())
+        .thenReturn(DownloadManagerState.DownloadState.IN_PROGRESS);
     final ReliableResourceInputStream is =
         new ReliableResourceInputStream(
             fbos, countingFbos, downloadState, downloadIdentifier, resourceResponse);
     is.setCallableAndItsFuture(reliableResourceCallable, downloadFuture);
-    byte[] bytes = new String("Hello World").getBytes();
+    byte[] bytes = "Hello World".getBytes();
     countingFbos.write(bytes, 0, bytes.length);
     final byte[] buffer = new byte[50];
     int numBytesRead = is.read(buffer, 0, buffer.length);
@@ -163,33 +165,33 @@ public void testReadByteBufferBlocksUntilNewFbosBytesWritten() throws Exception
     // to FileBackedOutputStream)
 
     Callable<Integer> callable =
-        new Callable<Integer>() {
-          @Override
-          public Integer call() {
-            int numBytesRead2 = 0;
-            try {
-              numBytesRead2 = is.read(buffer, 0, buffer.length);
-            } catch (IOException e) {
-              LOGGER.info("Failed to read bytes second time", e);
-            }
-            return numBytesRead2;
+        () -> {
+          int numBytesRead2 = 0;
+          try {
+            numBytesRead2 = is.read(buffer, 0, buffer.length);
+          } catch (IOException e) {
+            LOGGER.info("Failed to read bytes second time", e);
           }
+          return numBytesRead2;
         };
 
     ExecutorService executor = Executors.newCachedThreadPool();
     Future<Integer> future = executor.submit(callable);
 
-    // Write second string to FileBackedOutputStream - ReliableResourceInputStream's running
-    // read(byte[], off, len) method is in loop waiting for new bytes to be written and should
-    // detect this, read the new bytes and put them in the buffer
-    String secondString = "Hello a second time";
-    byte[] bytes2 = secondString.getBytes();
-    countingFbos.write(bytes2, 0, bytes2.length);
-    Integer bytesReadCount = future.get();
-    assertThat(bytesReadCount, is(bytes2.length));
-    assertThat(new String(buffer), containsString(secondString));
-
-    is.close();
+    try {
+      // Write second string to FileBackedOutputStream - ReliableResourceInputStream's running
+      // read(byte[], off, len) method is in loop waiting for new bytes to be written and should
+      // detect this, read the new bytes and put them in the buffer
+      String secondString = "Hello a second time";
+      byte[] bytes2 = secondString.getBytes();
+      countingFbos.write(bytes2, 0, bytes2.length);
+      Integer bytesReadCount = future.get();
+      assertThat(bytesReadCount, is(bytes2.length));
+      assertThat(new String(buffer), containsString(secondString));
+    } finally {
+      executor.shutdownNow();
+      is.close();
+    }
   }
 
   @Test(expected = NullPointerException.class)