Activate tests in maven

By adding the testSourceDirectory, the `mvn test`
target can be used in intellij to run tests. This
detected an NPE on `axes` that I've fixed here
though it would be more appropriate for omegh-8.

pom.xml

@@ -118,10 +118,10 @@
 
   </dependencies>
 
-    <properties>
+  <properties>
     <project.rootdir>${basedir}/../..</project.rootdir>
     <maven.compiler.source>1.8</maven.compiler.source>
-   <maven.compiler.target>1.8</maven.compiler.target>
+    <maven.compiler.target>1.8</maven.compiler.target>
   </properties>
 
 <!--   <build> -->
@@ -154,6 +154,7 @@
 <!--   </build> -->
   <build>
     <sourceDirectory>${project.basedir}/src</sourceDirectory>
+    <testSourceDirectory>${project.basedir}/src/test</testSourceDirectory>
     <plugins>
       <plugin>
         <groupId>org.apache.maven.plugins</groupId>

src/loci/formats/in/ZarrReader.java

@@ -31,6 +31,7 @@
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.HashMap;
+import java.util.List;
 import java.util.Map;
 
 import javax.xml.parsers.ParserConfigurationException;
@@ -491,7 +492,7 @@ private void parseResolutionCount(String root, String key) throws IOException, F
         list.add(key.isEmpty() ? scalePath : key + File.separator + scalePath);
         resSeries.put(resCounts.size() - 1, list);
       }
-      ArrayList<Object> multiscaleAxes = (ArrayList<Object>)datasets.get("axes");
+      List<String> multiscaleAxes = (List<String>)datasets.get("axes");
       for (int i = 0; i < multiscaleAxes.size(); i++) {
         String axis = (String) multiscaleAxes.get(i);
       }

src/test/loci/formats/utests/ZarrReaderTest.java

@@ -8,6 +8,7 @@
 import java.io.File;
 import java.io.IOException;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Map;
@@ -64,6 +65,7 @@ public void setUp() throws Exception {
     multiscalePaths.add(multiScale2);
     multiscalePaths.add(multiScale3);
     datasets.put("datasets", multiscalePaths);
+    datasets.put("axes", Arrays.asList("t", "c", "z", "y", "x"));
     multiscales.add(datasets);
     topLevelAttributes.put("multiscales", multiscales);