diff --git a/pom.xml b/pom.xml
index 58ddc06b..c4ce941a 100644
--- a/pom.xml
+++ b/pom.xml
@@ -214,4 +214,19 @@
 			<url>https://maven.scijava.org/content/groups/public</url>
 		</repository>
 	</repositories>
+
+	<build>
+		<plugins>
+			<plugin>
+				<groupId>org.apache.maven.plugins</groupId>
+				<artifactId>maven-surefire-plugin</artifactId>
+				<configuration>
+					<forkCount>1</forkCount>
+					<reuseForks>true</reuseForks>
+				</configuration>
+			</plugin>
+		</plugins>
+	</build>
+
+
 </project>
diff --git a/src/test/java/org/janelia/saalfeldlab/n5/MetadataIoTests.java b/src/test/java/org/janelia/saalfeldlab/n5/MetadataIoTests.java
index 587a1eeb..269c4842 100644
--- a/src/test/java/org/janelia/saalfeldlab/n5/MetadataIoTests.java
+++ b/src/test/java/org/janelia/saalfeldlab/n5/MetadataIoTests.java
@@ -34,6 +34,7 @@
 import java.util.Optional;
 import java.util.stream.IntStream;
 
+import org.codehaus.plexus.util.FileUtils;
 import org.janelia.saalfeldlab.n5.hdf5.N5HDF5Writer;
 import org.janelia.saalfeldlab.n5.ij.N5IJUtils;
 import org.janelia.saalfeldlab.n5.metadata.imagej.CosemToImagePlus;
@@ -53,8 +54,9 @@
 import org.janelia.saalfeldlab.n5.universe.metadata.N5SingleScaleMetadataParser;
 import org.janelia.saalfeldlab.n5.universe.metadata.N5ViewerMultiscaleMetadataParser;
 import org.janelia.saalfeldlab.n5.zarr.N5ZarrWriter;
+import org.junit.AfterClass;
 import org.junit.Assert;
-import org.junit.Before;
+import org.junit.BeforeClass;
 import org.junit.Test;
 
 import ij.ImagePlus;
@@ -65,7 +67,7 @@
 
 public class MetadataIoTests
 {
-	static private String testDirPath = createTestDirPath("n5-test");
+	private static String testDirPath = createTestDirPath("n5-ij-metatest-");
 	private static String createTestDirPath(String dirName) {
 		try {
 			return Files.createTempDirectory(dirName).toString();
@@ -75,13 +77,13 @@ private static String createTestDirPath(String dirName) {
 	}
 	static private String testBaseDatasetName = "/test/data";
 
-	private ImagePlus imp2d;
-	private ImagePlus imp3d;
-	private ImagePlus imp4d;
-	private ImagePlus imp5d;
+	private static ImagePlus imp2d;
+	private static ImagePlus imp3d;
+	private static ImagePlus imp4d;
+	private static ImagePlus imp5d;
 
-	@Before
-	public void setUp() throws IOException
+	@BeforeClass
+	public static void setUp() throws IOException
 	{
 		final ArrayImgFactory< UnsignedByteType > factory = new ArrayImgFactory<>( new UnsignedByteType() );
 
@@ -108,6 +110,18 @@ public void setUp() throws IOException
 		imp5d.getCalibration().pixelDepth = 1.1;
 	}
 
+	@AfterClass
+	public static void tearDown() {
+
+		try {
+			final File d = new File(testDirPath);
+			FileUtils.deleteDirectory(d);
+			d.delete();
+		} catch (IOException e) {
+			e.printStackTrace();
+		}
+	}
+
 	@Test
 	public void testCustomMetadata()
 	{
@@ -117,7 +131,7 @@ public void testCustomMetadata()
 		N5FSWriter n5 = null;
 		try
 		{
-			n5 = new N5FSWriter( testDirPath+ ".n5" );
+			n5 = new N5FSWriter(new File(testDirPath, "testCustom.n5").getAbsolutePath());
 			n5.createDataset( "/testpath",
 				new long[]{2,3,4}, new int[] {2,3,4}, DataType.UINT8 , new RawCompression() );
 
@@ -245,8 +259,9 @@ public void testCosem()
 	@Test
 	public void testH5()
 	{
-		final N5HDF5Writer n5 = new N5HDF5Writer( testDirPath + ".h5", 32, 32, 32, 32, 32 );
-		testAllMetadataTypes( n5 );
+		final N5HDF5Writer h5 = new N5HDF5Writer( new File( testDirPath, "test.h5").getAbsolutePath(), 32, 32, 32, 32, 32 );
+		testAllMetadataTypes( h5 );
+		h5.close();
 	}
 
 	@Test
@@ -254,19 +269,21 @@ public void testZarr()
 	{
 		try
 		{
-			final N5ZarrWriter n5 = new N5ZarrWriter( testDirPath+ ".zarr" );
-			testAllMetadataTypes( n5 );
+			final N5ZarrWriter zarr = new N5ZarrWriter(new File(testDirPath, "test.zarr").getAbsolutePath());
+			testAllMetadataTypes( zarr );
 
-			n5.remove(  testBaseDatasetName + "/imp2d" );
-			n5.remove(  testBaseDatasetName + "/imp2_cosemd" );
-			n5.remove(  testBaseDatasetName + "/imp2_n5v" );
+			zarr.remove(  testBaseDatasetName + "/imp2d" );
+			zarr.remove(  testBaseDatasetName + "/imp2_cosemd" );
+			zarr.remove(  testBaseDatasetName + "/imp2_n5v" );
 
-			n5.remove(  testBaseDatasetName + "/imp3d" );
-			n5.remove(  testBaseDatasetName + "/imp3d_cosem" );
-			n5.remove(  testBaseDatasetName + "/imp3d_n5v" );
+			zarr.remove(  testBaseDatasetName + "/imp3d" );
+			zarr.remove(  testBaseDatasetName + "/imp3d_cosem" );
+			zarr.remove(  testBaseDatasetName + "/imp3d_n5v" );
 
-			n5.remove(  testBaseDatasetName + "/imp4d" );
-			n5.remove(  testBaseDatasetName + "/imp5d" );
+			zarr.remove(  testBaseDatasetName + "/imp4d" );
+			zarr.remove(  testBaseDatasetName + "/imp5d" );
+
+			zarr.close();
 		}
 		catch ( final N5Exception e )
 		{
@@ -281,7 +298,7 @@ public void testN5FileSystem()
 		N5FSWriter n5;
 		try
 		{
-			n5 = new N5FSWriter( testDirPath+ ".n5" );
+			n5 = new N5FSWriter(new File(testDirPath, "test.n5").getAbsolutePath());
 			testAllMetadataTypes( n5 );
 
 			n5.remove(  testBaseDatasetName + "/imp2d" );
@@ -294,6 +311,8 @@ public void testN5FileSystem()
 
 			n5.remove(  testBaseDatasetName + "/imp4d" );
 			n5.remove(  testBaseDatasetName + "/imp5d" );
+
+			n5.close();
 		}
 		catch ( final N5Exception e )
 		{
diff --git a/src/test/java/org/janelia/saalfeldlab/n5/TestExportImports.java b/src/test/java/org/janelia/saalfeldlab/n5/TestExportImports.java
index 7b4d5182..502d5064 100644
--- a/src/test/java/org/janelia/saalfeldlab/n5/TestExportImports.java
+++ b/src/test/java/org/janelia/saalfeldlab/n5/TestExportImports.java
@@ -2,6 +2,7 @@
 
 import static org.junit.Assert.assertArrayEquals;
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;
 
@@ -28,9 +29,9 @@
 import org.janelia.saalfeldlab.n5.universe.metadata.ome.ngff.v04.NgffSingleScaleMetadataParser;
 import org.janelia.saalfeldlab.n5.zarr.N5ZarrReader;
 import org.janelia.saalfeldlab.n5.zarr.N5ZarrWriter;
-import org.junit.After;
+import org.junit.AfterClass;
 import org.junit.Assert;
-import org.junit.Before;
+import org.junit.BeforeClass;
 import org.junit.Test;
 
 import ij.ImagePlus;
@@ -49,10 +50,10 @@
 public class TestExportImports
 {
 
-	private File baseDir;
+	private static File baseDir;
 
-	@Before
-	public void before() {
+	@BeforeClass
+	public static void setup() {
 
 		final URL configUrl = RunImportExportTest.class.getResource("/plugins.config");
 		baseDir = new File(configUrl.getFile()).getParentFile();
@@ -65,20 +66,25 @@ public void before() {
 		}
 	}
 
-	@After
-	public void after() {
+	@AfterClass
+	public static void tearDown() {
 
 		baseDir.delete();
 	}
 
-	private boolean deleteContainer(final String rootPath) {
+	private static boolean deleteContainer(final String rootPath) {
 
-		N5Writer n5w = new N5Factory().openWriter(rootPath);
-		return n5w.remove();
+		try ( final N5Writer n5w = new N5Factory().openWriter(rootPath) ) {
+			return n5w.remove();
+		} catch( N5Exception e ) {
+			e.printStackTrace();
+		}
+
+		return false;
 	}
 
 	@Test
-	public void testEmptyMeta()
+	public void testEmptyMeta() throws InterruptedException
 	{
 		final ImagePlus imp = NewImage.createImage("test", 8, 6, 2, 16, NewImage.FILL_NOISE);
 		final String metaType = N5Importer.MetadataDefaultKey;
@@ -127,7 +133,7 @@ public void test4dN5v()
 	}
 
 	@Test
-	public void testReadWriteParse()
+	public void testReadWriteParse() throws InterruptedException
 	{
 		final HashMap<String,String> typeToExtension = new HashMap<>();
 		typeToExtension.put( "FILESYSTEM", "n5" );
@@ -152,11 +158,12 @@ public void testReadWriteParse()
 			{
 				for( final String metatype : metadataTypes )
 				{
-					final String n5RootPath = baseDir + "/test." + typeToExtension.get( containerType );
+					final String n5RootPath = baseDir + "/test-" + metatype + "-" + bitDepth + "." + typeToExtension.get( containerType );
 					final String datasetBase = "/test_"+metatype+"_"+bitDepth;
 					final String dataset = datasetBase;
 
 					singleReadWriteParseTest( imp, n5RootPath, dataset, blockSizeString, metatype, compressionString, true );
+					Thread.sleep(25);
 				}
 			}
 		}
@@ -249,12 +256,12 @@ public void singleReadWriteParseTest(
 			final String blockSizeString,
 			final String metadataType,
 			final String compressionType,
-			final boolean testMeta )
+			final boolean testMeta ) throws InterruptedException
 	{
 		singleReadWriteParseTest( imp, outputPath, dataset, blockSizeString, metadataType, compressionType, testMeta, true);
 	}
 
-	public void singleReadWriteParseTest(
+	public static void singleReadWriteParseTest(
 			final ImagePlus imp,
 			final String outputPath,
 			final String dataset,
@@ -262,7 +269,7 @@ public void singleReadWriteParseTest(
 			final String metadataType,
 			final String compressionType,
 			final boolean testMeta,
-			final boolean testData )
+			final boolean testData ) throws InterruptedException
 	{
 		final N5ScalePyramidExporter writer = new N5ScalePyramidExporter();
 		writer.setOptions( imp, outputPath, dataset, N5ScalePyramidExporter.AUTO_FORMAT, blockSizeString, false,
@@ -279,10 +286,19 @@ else if (metadataType.equals(N5Importer.MetadataOmeZarrKey) || metadataType.equa
 
 		final String n5PathAndDataset = outputPath + readerDataset;
 
+		final File n5RootWritten = new File(outputPath);
+		assertTrue("root does not exist: " + outputPath, n5RootWritten.exists());
+		if (outputPath.endsWith(".h5"))
+			assertTrue("hdf5 file exists", n5RootWritten.exists());
+		else
+			assertTrue("n5 or zarr root is not a directory:" + outputPath, n5RootWritten.isDirectory());
+
+		Thread.sleep(25);
 		final N5Importer reader = new N5Importer();
 		reader.setShow( false );
 		final List< ImagePlus > impList = reader.process( n5PathAndDataset, false );
 
+		assertNotNull(String.format( "Failed to open image: %s %s ", outputPath, dataset ), impList);
 		assertEquals( String.format( "%s %s one image opened ", outputPath, dataset ), 1, impList.size() );
 
 		final double EPS = 1e-9;
@@ -293,8 +309,7 @@ else if (metadataType.equals(N5Importer.MetadataOmeZarrKey) || metadataType.equa
 			assertEquals( String.format( "%s resolutions y", dataset ), imp.getCalibration().pixelHeight, impRead.getCalibration().pixelHeight, EPS );
 			assertEquals( String.format( "%s resolutions z", dataset ), imp.getCalibration().pixelDepth, impRead.getCalibration().pixelDepth, EPS );
 
-			final boolean unitsEqual = impRead.getCalibration().getUnit().equals( imp.getCalibration().getUnit() );
-			assertTrue( String.format( "%s units ", dataset ), unitsEqual );
+			final boolean unitsEqual = impRead.getCalibration().getUnit().equals( imp.getCalibration().getUnit() ); assertTrue( String.format( "%s units ", dataset ), unitsEqual );
 		}
 
 		if( testData )
@@ -311,19 +326,12 @@ else if (metadataType.equals(N5Importer.MetadataOmeZarrKey) || metadataType.equa
 			assertTrue( String.format( "%s data ", dataset ), imagesEqual );
 		}
 
-		try {
-			final N5Writer n5w = new N5Factory().openWriter(outputPath);
-			n5w.remove();
-		} catch (final N5Exception e) {
-			e.printStackTrace();
-		}
-
 		impRead.close();
-
+		deleteContainer(outputPath);
 	}
 
 	@Test
-	public void testRgb()
+	public void testRgb() throws InterruptedException
 	{
 		final ImagePlus imp = NewImage.createRGBImage("test", 8, 6, 4, NewImage.FILL_NOISE);
 		final String metaType = N5Importer.MetadataImageJKey;
@@ -346,10 +354,14 @@ public void testMultiChannel()
 	{
 		for( final String suffix : new String[] { ".h5", ".n5", ".zarr" })
 		{
-			testMultiChannelHelper(N5Importer.MetadataN5ViewerKey, suffix);
-			testMultiChannelHelper(N5Importer.MetadataN5CosemKey, suffix);
-			testMultiChannelHelper(N5Importer.MetadataOmeZarrKey, suffix);
-			testMultiChannelHelper(N5Importer.MetadataImageJKey, suffix);
+			try {
+				testMultiChannelHelper(N5Importer.MetadataN5ViewerKey, suffix);
+				testMultiChannelHelper(N5Importer.MetadataN5CosemKey, suffix);
+				testMultiChannelHelper(N5Importer.MetadataOmeZarrKey, suffix);
+				testMultiChannelHelper(N5Importer.MetadataImageJKey, suffix);
+			} catch (InterruptedException e) {
+				e.printStackTrace();
+			}
 		}
 	}
 
@@ -563,11 +575,9 @@ public void reset() {
 
 	}
 
-	public void testMultiChannelHelper( final String metatype, final String suffix )
+	public void testMultiChannelHelper( final String metatype, final String suffix ) throws InterruptedException
 	{
 		final int bitDepth = 8;
-
-		final String n5RootPath = baseDir + "/test_"+ metatype+"_dimCombos" + suffix;
 		final String blockSizeString = "16";
 		final String compressionString = "raw";
 
@@ -591,8 +601,11 @@ public void testMultiChannelHelper( final String metatype, final String suffix )
 					if( nz > 1 )
 						imp.getCalibration().pixelDepth = 0.7;
 
-					final String dataset = String.format("/c%dz%dt%d", nc, nz, nt);
+					final String dimCode = String.format("c%dz%dt%d", nc, nz, nt);
+					final String n5RootPath = baseDir + "/test_" + metatype + "_" + dimCode + suffix;
+					final String dataset = String.format("/%s", dimCode);
 					singleReadWriteParseTest( imp, n5RootPath, dataset, blockSizeString, metatype, compressionString, true, nc == 1 );
+					Thread.sleep(25);
 				}
 			}
 		}
diff --git a/src/test/java/org/janelia/saalfeldlab/n5/metadata/MetadataTests.java b/src/test/java/org/janelia/saalfeldlab/n5/metadata/MetadataTests.java
index 91d63165..bda8e672 100644
--- a/src/test/java/org/janelia/saalfeldlab/n5/metadata/MetadataTests.java
+++ b/src/test/java/org/janelia/saalfeldlab/n5/metadata/MetadataTests.java
@@ -12,10 +12,9 @@
 import org.janelia.saalfeldlab.n5.universe.metadata.N5SingleScaleMetadataParser;
 import org.janelia.saalfeldlab.n5.universe.metadata.SpatialMetadata;
 import org.junit.Assert;
-import org.junit.Before;
+import org.junit.BeforeClass;
 import org.junit.Test;
 
-import java.io.File;
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -30,20 +29,18 @@
 
 public class MetadataTests {
 
-  N5FSReader n5;
+  private static N5FSReader n5;
 
-  @Before
-  public void setUp() throws IOException {
+  @BeforeClass
+  public static void setUp() throws IOException {
 
 	final String n5Root = "src/test/resources/test.n5";
-	File n5rootF = new File(n5Root);
 	n5 = new N5FSReader(n5Root);
   }
 
   @Test
   public void testCosemMetadataMultiscale() {
 
-	final double eps = 1e-6;
 	final N5MetadataParser<?>[] parsers = new N5MetadataParser[]{new N5CosemMetadataParser()};
 	final N5MetadataParser<?>[] grpparsers = new N5MetadataParser[]{new N5CosemMultiScaleMetadata.CosemMultiScaleParser()};