Make BoundedReadFromUnboundedSourceTest work across runners

sdks/java/core/src/test/java/com/google/cloud/dataflow/sdk/io/BoundedReadFromUnboundedSourceTest.java

@@ -95,7 +95,7 @@ public Void apply(Iterable<KV<Integer, Integer>> input) {
       Collections.sort(values);
       for (int i = 0; i < values.size(); i++) {
         assertEquals(i, (int) values.get(i));
-              }
+      }
       if (finalizeTracker != null) {
         assertThat(finalizeTracker, containsInAnyOrder(values.size() - 1));
       }
@@ -110,7 +110,7 @@ private void test(boolean dedup, boolean timeBound) throws Exception {
       finalizeTracker = new ArrayList<>();
       TestCountingSource.setFinalizeTracker(finalizeTracker);
     }
-    TestCountingSource source = new TestCountingSource(Integer.MAX_VALUE);
+    TestCountingSource source = new TestCountingSource(Integer.MAX_VALUE).withoutSplitting();
     if (dedup) {
       source = source.withDedup();
     }

sdks/java/core/src/test/java/com/google/cloud/dataflow/sdk/runners/dataflow/TestCountingSource.java

@@ -56,6 +56,7 @@ public class TestCountingSource
   private final int shardNumber;
   private final boolean dedup;
   private final boolean throwOnFirstSnapshot;
+  private final boolean allowSplitting;
 
   /**
    * We only allow an exception to be thrown from getCheckpointMark
@@ -69,27 +70,36 @@ public static void setFinalizeTracker(List<Integer> finalizeTracker) {
   }
 
   public TestCountingSource(int numMessagesPerShard) {
-    this(numMessagesPerShard, 0, false, false);
+    this(numMessagesPerShard, 0, false, false, true);
   }
 
   public TestCountingSource withDedup() {
-    return new TestCountingSource(numMessagesPerShard, shardNumber, true, throwOnFirstSnapshot);
+    return new TestCountingSource(
+        numMessagesPerShard, shardNumber, true, throwOnFirstSnapshot, true);
   }
 
   private TestCountingSource withShardNumber(int shardNumber) {
-    return new TestCountingSource(numMessagesPerShard, shardNumber, dedup, throwOnFirstSnapshot);
+    return new TestCountingSource(
+        numMessagesPerShard, shardNumber, dedup, throwOnFirstSnapshot, true);
   }
 
   public TestCountingSource withThrowOnFirstSnapshot(boolean throwOnFirstSnapshot) {
-    return new TestCountingSource(numMessagesPerShard, shardNumber, dedup, throwOnFirstSnapshot);
+    return new TestCountingSource(
+        numMessagesPerShard, shardNumber, dedup, throwOnFirstSnapshot, true);
   }
 
-  private TestCountingSource(
-      int numMessagesPerShard, int shardNumber, boolean dedup, boolean throwOnFirstSnapshot) {
+  public TestCountingSource withoutSplitting() {
+    return new TestCountingSource(
+        numMessagesPerShard, shardNumber, dedup, throwOnFirstSnapshot, false);
+  }
+
+  private TestCountingSource(int numMessagesPerShard, int shardNumber, boolean dedup,
+      boolean throwOnFirstSnapshot, boolean allowSplitting) {
     this.numMessagesPerShard = numMessagesPerShard;
     this.shardNumber = shardNumber;
     this.dedup = dedup;
     this.throwOnFirstSnapshot = throwOnFirstSnapshot;
+    this.allowSplitting = allowSplitting;
   }
 
   public int getShardNumber() {
@@ -100,7 +110,8 @@ public int getShardNumber() {
   public List<TestCountingSource> generateInitialSplits(
       int desiredNumSplits, PipelineOptions options) {
     List<TestCountingSource> splits = new ArrayList<>();
-    for (int i = 0; i < desiredNumSplits; i++) {
+    int numSplits = allowSplitting ? desiredNumSplits : 1;
+    for (int i = 0; i < numSplits; i++) {
       splits.add(withShardNumber(i));
     }
     return splits;