a bit more sleep to give IO a chance in the masively overusing compr…

…ession tests

src/test/java/org/apache/sysds/test/component/compress/io/IOSpark.java

@@ -276,7 +276,7 @@ private void testWriteSparkReadCP(MatrixBlock mb, int blen1, int blen2) {
 			Timing t = new Timing();
 			String f1 = getName();
 			WriterCompressed.writeCompressedMatrixToHDFS(mb, f1, blen1);
-
+			Thread.sleep(100);
 			// Make sure the first file is written
 			File f = new File(f1);
 			assertTrue(f.isFile() || f.isDirectory());
@@ -293,6 +293,7 @@ private void testWriteSparkReadCP(MatrixBlock mb, int blen1, int blen2) {
 			}
 			else
 				WriterCompressed.writeRDDToHDFS(m, f2);
+			Thread.sleep(100);
 
 			// Read locally the spark block written.
 			MatrixBlock mbr = IOCompressionTestUtils.read(f2);
@@ -312,7 +313,7 @@ private void testReblock(MatrixBlock mb, int blen1, int blen2) {
 
 			String f1 = getName();
 			WriterCompressed.writeCompressedMatrixToHDFS(mb, f1, blen1);
-
+			Thread.sleep(100);
 			// Read in again as RDD
 			JavaPairRDD<MatrixIndexes, MatrixBlock> m = getRDD(f1); // Our starting point
 
@@ -361,6 +362,7 @@ public void readRDDThroughSparkExecutionContext(MatrixBlock mb, int blen) {
 			String n = getName();
 
 			WriterCompressed.writeCompressedMatrixToHDFS(mb, n, blen);
+			Thread.sleep(100);
 			MatrixReader r = ReaderCompressed.create();
 			MatrixBlock mb2 = r.readMatrixFromHDFS(n, (long) mb.getNumRows(), (long) mb.getNumColumns(), blen, -1L);
 			TestUtils.compareMatricesBitAvgDistance(mb, mb2, 0, 0);