YARN-9270. Minor cleanup in TestFpgaDiscoverer. Contributed by Peter Bacsko.

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/main/java/org/apache/hadoop/yarn/server/nodemanager/containermanager/linux/resources/fpga/FpgaResourceHandlerImpl.java

@@ -64,6 +64,8 @@ public class FpgaResourceHandlerImpl implements ResourceHandler {
 
   private final CGroupsHandler cGroupsHandler;
 
+  private final FpgaDiscoverer fpgaDiscoverer;
+
   public static final String EXCLUDED_FPGAS_CLI_OPTION = "--excluded_fpgas";
   public static final String CONTAINER_ID_CLI_OPTION = "--container_id";
   private PrivilegedOperationExecutor privilegedOperationExecutor;
@@ -72,10 +74,11 @@ public class FpgaResourceHandlerImpl implements ResourceHandler {
   public FpgaResourceHandlerImpl(Context nmContext,
       CGroupsHandler cGroupsHandler,
       PrivilegedOperationExecutor privilegedOperationExecutor,
-      AbstractFpgaVendorPlugin plugin) {
+      AbstractFpgaVendorPlugin plugin,
+      FpgaDiscoverer fpgaDiscoverer) {
     this.allocator = new FpgaResourceAllocator(nmContext);
     this.vendorPlugin = plugin;
-    FpgaDiscoverer.getInstance().setResourceHanderPlugin(vendorPlugin);
+    this.fpgaDiscoverer = fpgaDiscoverer;
     this.cGroupsHandler = cGroupsHandler;
     this.privilegedOperationExecutor = privilegedOperationExecutor;
   }
@@ -99,8 +102,7 @@ public class FpgaResourceHandlerImpl implements ResourceHandler {
     }
     LOG.info("FPGA Plugin bootstrap success.");
     // Get avialable devices minor numbers from toolchain or static configuration
-    List<FpgaResourceAllocator.FpgaDevice> fpgaDeviceList =
-        FpgaDiscoverer.getInstance().discover();
+    List<FpgaDevice> fpgaDeviceList = fpgaDiscoverer.discover();
     allocator.addFpgaDevices(vendorPlugin.getFpgaType(), fpgaDeviceList);
     this.cGroupsHandler.initializeCGroupController(
         CGroupsHandler.CGroupController.DEVICES);
@@ -183,7 +185,7 @@ public class FpgaResourceHandlerImpl implements ResourceHandler {
               " if you want YARN to program the device");
         } else {
           LOG.info("IP file path:" + ipFilePath);
-          List<FpgaResourceAllocator.FpgaDevice> allowed = allocation.getAllowed();
+          List<FpgaDevice> allowed = allocation.getAllowed();
           String majorMinorNumber;
           for (int i = 0; i < allowed.size(); i++) {
             FpgaDevice device = allowed.get(i);

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/main/java/org/apache/hadoop/yarn/server/nodemanager/containermanager/resourceplugin/fpga/FpgaDiscoverer.java

@@ -34,6 +34,7 @@ import org.apache.hadoop.yarn.conf.YarnConfiguration;
 import org.apache.hadoop.yarn.exceptions.YarnException;
 import org.apache.hadoop.yarn.server.nodemanager.containermanager.linux.resources.ResourceHandlerException;
 import org.apache.hadoop.yarn.server.nodemanager.containermanager.linux.resources.fpga.FpgaResourceAllocator;
+import org.apache.hadoop.yarn.server.nodemanager.containermanager.linux.resources.fpga.FpgaResourceAllocator.FpgaDevice;
 import org.apache.hadoop.yarn.server.nodemanager.containermanager.resourceplugin.fpga.discovery.AoclOutputBasedDiscoveryStrategy;
 import org.apache.hadoop.yarn.server.nodemanager.containermanager.resourceplugin.fpga.discovery.FPGADiscoveryStrategy;
 import org.apache.hadoop.yarn.server.nodemanager.containermanager.resourceplugin.fpga.discovery.ScriptBasedFPGADiscoveryStrategy;
@@ -49,12 +50,8 @@ public class FpgaDiscoverer {
   private static final Logger LOG = LoggerFactory.getLogger(
       FpgaDiscoverer.class);
 
-  private static FpgaDiscoverer instance;
-
   private Configuration conf = null;
-
   private AbstractFpgaVendorPlugin plugin = null;
-
   private List<FpgaResourceAllocator.FpgaDevice> currentFpgaInfo = null;
 
   private Function<String, Optional<String>> scriptRunner = this::runScript;
@@ -62,36 +59,17 @@ public class FpgaDiscoverer {
   // shell command timeout
   public static final int MAX_EXEC_TIMEOUT_MS = 10 * 1000;
 
-  static {
-    instance = new FpgaDiscoverer();
-  }
-
-  public static FpgaDiscoverer getInstance() {
-    return instance;
-  }
-
   @VisibleForTesting
   void setScriptRunner(Function<String, Optional<String>> scriptRunner) {
     this.scriptRunner = scriptRunner;
   }
 
-  @VisibleForTesting
-  static void reset() {
-    instance = new FpgaDiscoverer();
-  }
-
-  @VisibleForTesting
-  public static FpgaDiscoverer setInstance(FpgaDiscoverer newInstance) {
-    instance = newInstance;
-    return instance;
-  }
-
   @VisibleForTesting
   public void setConf(Configuration configuration) {
     this.conf = configuration;
   }
 
-  public List<FpgaResourceAllocator.FpgaDevice> getCurrentFpgaInfo() {
+  public List<FpgaDevice> getCurrentFpgaInfo() {
     return currentFpgaInfo;
   }
 
@@ -119,9 +97,9 @@ public class FpgaDiscoverer {
    * @return the list of FPGA devices
    * @throws ResourceHandlerException if there's any error during discovery
    **/
-  public List<FpgaResourceAllocator.FpgaDevice> discover()
+  public List<FpgaDevice> discover()
       throws ResourceHandlerException {
-    List<FpgaResourceAllocator.FpgaDevice> list;
+    List<FpgaDevice> list;
     String allowed = this.conf.get(YarnConfiguration.NM_FPGA_ALLOWED_DEVICES);
 
     String availableDevices = conf.get(

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/main/java/org/apache/hadoop/yarn/server/nodemanager/containermanager/resourceplugin/fpga/FpgaNodeResourceUpdateHandler.java

@@ -19,7 +19,6 @@
 
 package org.apache.hadoop.yarn.server.nodemanager.containermanager.resourceplugin.fpga;
 
-
 import static org.apache.hadoop.yarn.api.records.ResourceInformation.FPGA_URI;
 
 import java.util.LinkedList;
@@ -30,22 +29,28 @@ import org.apache.hadoop.yarn.api.records.Resource;
 import org.apache.hadoop.yarn.api.records.ResourceInformation;
 import org.apache.hadoop.yarn.conf.YarnConfiguration;
 import org.apache.hadoop.yarn.exceptions.YarnException;
-import org.apache.hadoop.yarn.server.nodemanager.containermanager.linux.resources.fpga.FpgaResourceAllocator;
+import org.apache.hadoop.yarn.server.nodemanager.containermanager.linux.resources.fpga.FpgaResourceAllocator.FpgaDevice;
 import org.apache.hadoop.yarn.server.nodemanager.containermanager.resourceplugin.NodeResourceUpdaterPlugin;
 import org.apache.hadoop.yarn.util.resource.ResourceUtils;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 public class FpgaNodeResourceUpdateHandler extends NodeResourceUpdaterPlugin {
+  private final FpgaDiscoverer fpgaDiscoverer;
+
   private static final Logger LOG = LoggerFactory.getLogger(
       FpgaNodeResourceUpdateHandler.class);
 
+  public FpgaNodeResourceUpdateHandler(FpgaDiscoverer fpgaDiscoverer) {
+    this.fpgaDiscoverer = fpgaDiscoverer;
+  }
+
   @Override
   public void updateConfiguredResource(Resource res) throws YarnException {
     LOG.info("Initializing configured FPGA resources for the NodeManager.");
-    List<FpgaResourceAllocator.FpgaDevice> list = FpgaDiscoverer.getInstance().getCurrentFpgaInfo();
+    List<FpgaDevice> list = fpgaDiscoverer.getCurrentFpgaInfo();
     List<Integer> minors = new LinkedList<>();
-    for (FpgaResourceAllocator.FpgaDevice device : list) {
+    for (FpgaDevice device : list) {
       minors.add(device.getMinor());
     }
     if (minors.isEmpty()) {

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/main/java/org/apache/hadoop/yarn/server/nodemanager/containermanager/resourceplugin/fpga/FpgaResourcePlugin.java

@@ -44,6 +44,7 @@ public class FpgaResourcePlugin implements ResourcePlugin {
 
   private AbstractFpgaVendorPlugin vendorPlugin = null;
   private FpgaNodeResourceUpdateHandler fpgaNodeResourceUpdateHandler = null;
+  private FpgaDiscoverer fpgaDiscoverer;
 
   private AbstractFpgaVendorPlugin createFpgaVendorPlugin(Configuration conf) {
     String vendorPluginClass = conf.get(YarnConfiguration.NM_FPGA_VENDOR_PLUGIN,
@@ -68,9 +69,11 @@ public class FpgaResourcePlugin implements ResourcePlugin {
   public void initialize(Context context) throws YarnException {
     // Get vendor plugin from configuration
     this.vendorPlugin = createFpgaVendorPlugin(context.getConf());
-    FpgaDiscoverer.getInstance().setResourceHanderPlugin(vendorPlugin);
-    FpgaDiscoverer.getInstance().initialize(context.getConf());
-    fpgaNodeResourceUpdateHandler = new FpgaNodeResourceUpdateHandler();
+    fpgaDiscoverer = new FpgaDiscoverer();
+    fpgaDiscoverer.setResourceHanderPlugin(vendorPlugin);
+    fpgaDiscoverer.initialize(context.getConf());
+    fpgaNodeResourceUpdateHandler =
+        new FpgaNodeResourceUpdateHandler(fpgaDiscoverer);
   }
 
   @Override
@@ -79,7 +82,8 @@ public class FpgaResourcePlugin implements ResourcePlugin {
       PrivilegedOperationExecutor privilegedOperationExecutor) {
     if (fpgaResourceHandler == null) {
       fpgaResourceHandler = new FpgaResourceHandlerImpl(nmContext,
-          cGroupsHandler, privilegedOperationExecutor, vendorPlugin);
+          cGroupsHandler, privilegedOperationExecutor, vendorPlugin,
+          fpgaDiscoverer);
     }
     return fpgaResourceHandler;
   }

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/test/java/org/apache/hadoop/yarn/server/nodemanager/containermanager/linux/resources/fpga/TestFpgaResourceHandler.java

@@ -51,6 +51,7 @@ import org.apache.hadoop.yarn.api.records.ContainerLaunchContext;
 import org.apache.hadoop.yarn.api.records.Resource;
 import org.apache.hadoop.yarn.api.records.ResourceInformation;
 import org.apache.hadoop.yarn.conf.YarnConfiguration;
+import org.apache.hadoop.yarn.exceptions.YarnException;
 import org.apache.hadoop.yarn.server.nodemanager.Context;
 import org.apache.hadoop.yarn.server.nodemanager.containermanager.container.Container;
 import org.apache.hadoop.yarn.server.nodemanager.containermanager.container.ResourceMappings;
@@ -91,16 +92,18 @@ public class TestFpgaResourceHandler {
   private ConcurrentHashMap<ContainerId, Container> runningContainersMap;
   private IntelFpgaOpenclPlugin mockVendorPlugin;
   private List<FpgaDevice> deviceList;
+  private FpgaDiscoverer fpgaDiscoverer;
   private static final String vendorType = "IntelOpenCL";
   private File dummyAocx;
 
   private String getTestParentFolder() {
-    File f = new File("target/temp/" + TestFpgaResourceHandler.class.getName());
+    File f = new File("target/temp/" +
+        TestFpgaResourceHandler.class.getName());
     return f.getAbsolutePath();
   }
 
   @Before
-  public void setup() throws IOException {
+  public void setup() throws IOException, YarnException {
     CustomResourceTypesConfigurationProvider.
         initResourceTypes(ResourceInformation.FPGA_URI);
     configuration = new YarnConfiguration();
@@ -116,13 +119,16 @@ public class TestFpgaResourceHandler {
     }
     String aocxPath = getTestParentFolder() + "/test.aocx";
     mockVendorPlugin = mockPlugin(vendorType, deviceList, aocxPath);
-    FpgaDiscoverer.getInstance().setConf(configuration);
+    fpgaDiscoverer = new FpgaDiscoverer();
+    fpgaDiscoverer.setResourceHanderPlugin(mockVendorPlugin);
+    fpgaDiscoverer.initialize(configuration);
     when(mockContext.getNMStateStore()).thenReturn(mockNMStateStore);
     runningContainersMap = new ConcurrentHashMap<>();
     when(mockContext.getContainers()).thenReturn(runningContainersMap);
 
     fpgaResourceHandler = new FpgaResourceHandlerImpl(mockContext,
-        mockCGroupsHandler, mockPrivilegedExecutor, mockVendorPlugin);
+        mockCGroupsHandler, mockPrivilegedExecutor, mockVendorPlugin,
+        fpgaDiscoverer);
 
     dummyAocx = new File(aocxPath);
     Files.createParentDirs(dummyAocx);
@@ -143,7 +149,8 @@ public class TestFpgaResourceHandler {
     String allowed = "auto";
     configuration.set(YarnConfiguration.NM_FPGA_ALLOWED_DEVICES, allowed);
     fpgaResourceHandler.bootstrap(configuration);
-    verify(mockVendorPlugin, times(1)).initPlugin(configuration);
+    // initPlugin() was also called in setup()
+    verify(mockVendorPlugin, times(2)).initPlugin(configuration);
     verify(mockCGroupsHandler, times(1)).initializeCGroupController(
         CGroupsHandler.CGroupController.DEVICES);
     Assert.assertEquals(5, fpgaResourceHandler.getFpgaAllocator()
@@ -152,7 +159,8 @@ public class TestFpgaResourceHandler {
         .getAllowedFpga().size());
     // Case 2. subset of devices
     fpgaResourceHandler = new FpgaResourceHandlerImpl(mockContext,
-        mockCGroupsHandler, mockPrivilegedExecutor, mockVendorPlugin);
+        mockCGroupsHandler, mockPrivilegedExecutor, mockVendorPlugin,
+        fpgaDiscoverer);
     allowed = "0,1,2";
     configuration.set(YarnConfiguration.NM_FPGA_ALLOWED_DEVICES, allowed);
     fpgaResourceHandler.bootstrap(configuration);
@@ -174,7 +182,8 @@ public class TestFpgaResourceHandler {
 
     // Case 3. User configuration contains invalid minor device number
     fpgaResourceHandler = new FpgaResourceHandlerImpl(mockContext,
-        mockCGroupsHandler, mockPrivilegedExecutor, mockVendorPlugin);
+        mockCGroupsHandler, mockPrivilegedExecutor, mockVendorPlugin,
+        fpgaDiscoverer);
     allowed = "0,1,7";
     configuration.set(YarnConfiguration.NM_FPGA_ALLOWED_DEVICES, allowed);
     fpgaResourceHandler.bootstrap(configuration);
@@ -509,7 +518,8 @@ public class TestFpgaResourceHandler {
     mockVendorPlugin =
         mockPlugin(vendorType, deviceList, dummyAocx.getAbsolutePath());
     fpgaResourceHandler = new FpgaResourceHandlerImpl(mockContext,
-        mockCGroupsHandler, mockPrivilegedExecutor, mockVendorPlugin);
+        mockCGroupsHandler, mockPrivilegedExecutor, mockVendorPlugin,
+        fpgaDiscoverer);
 
     fpgaResourceHandler.bootstrap(configuration);
     fpgaResourceHandler.preStart(mockContainer(0, 1, "GEMM"));

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/test/java/org/apache/hadoop/yarn/server/nodemanager/containermanager/resourceplugin/fpga/TestFpgaDiscoverer.java

@@ -28,8 +28,6 @@ import static org.mockito.Mockito.when;
 import java.io.File;
 import java.io.FileOutputStream;
 import java.io.IOException;
-import java.lang.reflect.Field;
-import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
@@ -41,6 +39,7 @@ import org.apache.hadoop.yarn.conf.YarnConfiguration;
 import org.apache.hadoop.yarn.exceptions.YarnException;
 import org.apache.hadoop.yarn.server.nodemanager.containermanager.linux.resources.ResourceHandlerException;
 import org.apache.hadoop.yarn.server.nodemanager.containermanager.linux.resources.fpga.FpgaResourceAllocator.FpgaDevice;
+import org.junit.After;
 import org.junit.Before;
 import org.junit.Rule;
 import org.junit.Test;
@@ -50,6 +49,11 @@ public class TestFpgaDiscoverer {
   @Rule
   public ExpectedException expected = ExpectedException.none();
 
+  private File fakeBinary;
+  private IntelFpgaOpenclPlugin openclPlugin;
+  private Configuration conf;
+  private FpgaDiscoverer fpgaDiscoverer;
+
   private String getTestParentFolder() {
     File f = new File("target/temp/" + TestFpgaDiscoverer.class.getName());
     return f.getAbsolutePath();
@@ -65,110 +69,97 @@ public class TestFpgaDiscoverer {
     File f = new File(folder);
     FileUtils.deleteDirectory(f);
     f.mkdirs();
-    FpgaDiscoverer.reset();
+
+    conf = new Configuration();
+
+    openclPlugin = new IntelFpgaOpenclPlugin();
+    openclPlugin.initPlugin(conf);
+    openclPlugin.setInnerShellExecutor(mockPuginShell());
+
+    fpgaDiscoverer = new FpgaDiscoverer();
+    fpgaDiscoverer.setResourceHanderPlugin(openclPlugin);
   }
 
-  // A dirty hack to modify the env of the current JVM itself - Dirty, but
-  // should be okay for testing.
-  @SuppressWarnings({ "rawtypes", "unchecked" })
-  private static void setNewEnvironmentHack(Map<String, String> newenv)
-      throws Exception {
-    try {
-      Class<?> cl = Class.forName("java.lang.ProcessEnvironment");
-      Field field = cl.getDeclaredField("theEnvironment");
-      field.setAccessible(true);
-      Map<String, String> env = (Map<String, String>) field.get(null);
-      env.clear();
-      env.putAll(newenv);
-      Field ciField = cl.getDeclaredField("theCaseInsensitiveEnvironment");
-      ciField.setAccessible(true);
-      Map<String, String> cienv = (Map<String, String>) ciField.get(null);
-      cienv.clear();
-      cienv.putAll(newenv);
-    } catch (NoSuchFieldException e) {
-      Class[] classes = Collections.class.getDeclaredClasses();
-      Map<String, String> env = System.getenv();
-      for (Class cl : classes) {
-        if ("java.util.Collections$UnmodifiableMap".equals(cl.getName())) {
-          Field field = cl.getDeclaredField("m");
-          field.setAccessible(true);
-          Object obj = field.get(env);
-          Map<String, String> map = (Map<String, String>) obj;
-          map.clear();
-          map.putAll(newenv);
-        }
-      }
+  @After
+  public void afterTest() {
+    if (fakeBinary != null) {
+      fakeBinary.delete();
     }
   }
 
   @Test
-  public void testLinuxFpgaResourceDiscoverPluginConfig() throws Exception {
-    Configuration conf = new Configuration(false);
-    FpgaDiscoverer discoverer = FpgaDiscoverer.getInstance();
-
-    IntelFpgaOpenclPlugin openclPlugin = new IntelFpgaOpenclPlugin();
-    // because FPGA discoverer is a singleton, we use setPlugin to make
-    // FpgaDiscoverer.getInstance().diagnose() work in openclPlugin.initPlugin()
-    discoverer.setResourceHanderPlugin(openclPlugin);
-    openclPlugin.initPlugin(conf);
-    openclPlugin.setInnerShellExecutor(mockPuginShell());
+  public void testExecutablePathWithoutExplicitConfig()
+      throws YarnException {
+    fpgaDiscoverer.initialize(conf);
 
-    discoverer.initialize(conf);
-    // Case 1. No configuration set for binary(no environment "ALTERAOCLSDKROOT" set)
     assertEquals("No configuration(no environment ALTERAOCLSDKROOT set)" +
-            "should return just a single binary name",
+            " should return just a single binary name",
         "aocl", openclPlugin.getPathToExecutable());
+  }
 
-    // Case 2. With correct configuration and file exists
-    File fakeBinary = new File(getTestParentFolder() + "/aocl");
-    conf.set(YarnConfiguration.NM_FPGA_PATH_TO_EXEC, getTestParentFolder() + "/aocl");
+  @Test
+  public void testExecutablePathWithCorrectConfig()
+      throws IOException, YarnException {
+    fakeBinary = new File(getTestParentFolder() + "/aocl");
+    conf.set(YarnConfiguration.NM_FPGA_PATH_TO_EXEC,
+        getTestParentFolder() + "/aocl");
     touchFile(fakeBinary);
-    discoverer.initialize(conf);
+
+    fpgaDiscoverer.initialize(conf);
+
     assertEquals("Correct configuration should return user setting",
         getTestParentFolder() + "/aocl", openclPlugin.getPathToExecutable());
+  }
+
+  @Test
+  public void testExecutablePathWhenFileDoesNotExist()
+      throws YarnException {
+    conf.set(YarnConfiguration.NM_FPGA_PATH_TO_EXEC,
+        getTestParentFolder() + "/aocl");
 
-    // Case 3. With correct configuration but file doesn't exists. Use default
-    fakeBinary.delete();
-    discoverer.initialize(conf);
-    assertEquals("Should return just a single binary name",
+    fpgaDiscoverer.initialize(conf);
+
+    assertEquals("File doesn't exists - expected a single binary name",
         "aocl", openclPlugin.getPathToExecutable());
+  }
 
-    // Case 4. Set a empty value
+  @Test
+  public void testExecutablePathWhenFileIsEmpty()
+      throws YarnException {
     conf.set(YarnConfiguration.NM_FPGA_PATH_TO_EXEC, "");
-    discoverer.initialize(conf);
+
+    fpgaDiscoverer.initialize(conf);
+
     assertEquals("configuration with empty string value, should use aocl",
         "aocl", openclPlugin.getPathToExecutable());
+  }
 
-    // Case 5. No configuration set for binary, but set environment "ALTERAOCLSDKROOT"
-    // we load the default configuration to start with
-    conf = new Configuration(true);
+  @Test
+  public void testExecutablePathWithSdkRootSet()
+      throws IOException, YarnException {
     fakeBinary = new File(getTestParentFolder() + "/bin/aocl");
     fakeBinary.getParentFile().mkdirs();
     touchFile(fakeBinary);
     Map<String, String> newEnv = new HashMap<String, String>();
     newEnv.put("ALTERAOCLSDKROOT", getTestParentFolder());
-    setNewEnvironmentHack(newEnv);
-    discoverer.initialize(conf);
+    openclPlugin.setEnvProvider(s -> {
+      return newEnv.get(s); });
+
+    fpgaDiscoverer.initialize(conf);
+
     assertEquals("No configuration but with environment ALTERAOCLSDKROOT set",
         getTestParentFolder() + "/bin/aocl", openclPlugin.getPathToExecutable());
-
   }
 
   @Test
   public void testDiscoveryWhenAvailableDevicesDefined()
       throws YarnException {
-    Configuration conf = new Configuration(false);
     conf.set(YarnConfiguration.NM_FPGA_AVAILABLE_DEVICES,
         "acl0/243:0,acl1/244:1");
-    FpgaDiscoverer discoverer = FpgaDiscoverer.getInstance();
 
-    IntelFpgaOpenclPlugin openclPlugin = new IntelFpgaOpenclPlugin();
-    discoverer.setResourceHanderPlugin(openclPlugin);
-    openclPlugin.initPlugin(conf);
-    openclPlugin.setInnerShellExecutor(mockPuginShell());
+    fpgaDiscoverer.initialize(conf);
+    List<FpgaDevice> devices = fpgaDiscoverer.discover();
 
-    discoverer.initialize(conf);
-    List<FpgaDevice> devices = discoverer.discover();
     assertEquals("Number of devices", 2, devices.size());
     FpgaDevice device0 = devices.get(0);
     FpgaDevice device1 = devices.get(1);
@@ -188,18 +179,11 @@ public class TestFpgaDiscoverer {
     expected.expect(ResourceHandlerException.class);
     expected.expectMessage("No FPGA devices were specified");
 
-    Configuration conf = new Configuration(false);
     conf.set(YarnConfiguration.NM_FPGA_AVAILABLE_DEVICES,
         "");
-    FpgaDiscoverer discoverer = FpgaDiscoverer.getInstance();
-
-    IntelFpgaOpenclPlugin openclPlugin = new IntelFpgaOpenclPlugin();
-    discoverer.setResourceHanderPlugin(openclPlugin);
-    openclPlugin.initPlugin(conf);
-    openclPlugin.setInnerShellExecutor(mockPuginShell());
 
-    discoverer.initialize(conf);
-    discoverer.discover();
+    fpgaDiscoverer.initialize(conf);
+    fpgaDiscoverer.discover();
   }
 
   @Test
@@ -208,37 +192,24 @@ public class TestFpgaDiscoverer {
     expected.expect(ResourceHandlerException.class);
     expected.expectMessage("Illegal device specification string");
 
-    Configuration conf = new Configuration(false);
     conf.set(YarnConfiguration.NM_FPGA_AVAILABLE_DEVICES,
         "illegal/243:0,acl1/244=1");
-    FpgaDiscoverer discoverer = FpgaDiscoverer.getInstance();
 
-    IntelFpgaOpenclPlugin openclPlugin = new IntelFpgaOpenclPlugin();
-    discoverer.setResourceHanderPlugin(openclPlugin);
-    openclPlugin.initPlugin(conf);
-    openclPlugin.setInnerShellExecutor(mockPuginShell());
-
-    discoverer.initialize(conf);
-    discoverer.discover();
+    fpgaDiscoverer.initialize(conf);
+    fpgaDiscoverer.discover();
   }
 
   @Test
   public void testDiscoveryWhenExternalScriptDefined()
       throws YarnException {
-    Configuration conf = new Configuration(false);
     conf.set(YarnConfiguration.NM_FPGA_DEVICE_DISCOVERY_SCRIPT,
         "/dummy/script");
-    FpgaDiscoverer discoverer = FpgaDiscoverer.getInstance();
 
-    IntelFpgaOpenclPlugin openclPlugin = new IntelFpgaOpenclPlugin();
-    discoverer.setResourceHanderPlugin(openclPlugin);
-    openclPlugin.initPlugin(conf);
-    openclPlugin.setInnerShellExecutor(mockPuginShell());
-    discoverer.setScriptRunner(s -> {
+    fpgaDiscoverer.setScriptRunner(s -> {
       return Optional.of("acl0/243:0,acl1/244:1"); });
+    fpgaDiscoverer.initialize(conf);
+    List<FpgaDevice> devices = fpgaDiscoverer.discover();
 
-    discoverer.initialize(conf);
-    List<FpgaDevice> devices = discoverer.discover();
     assertEquals("Number of devices", 2, devices.size());
     FpgaDevice device0 = devices.get(0);
     FpgaDevice device1 = devices.get(1);
@@ -258,20 +229,14 @@ public class TestFpgaDiscoverer {
     expected.expect(ResourceHandlerException.class);
     expected.expectMessage("No FPGA devices were specified");
 
-    Configuration conf = new Configuration(false);
     conf.set(YarnConfiguration.NM_FPGA_DEVICE_DISCOVERY_SCRIPT,
         "/dummy/script");
-    FpgaDiscoverer discoverer = FpgaDiscoverer.getInstance();
 
-    IntelFpgaOpenclPlugin openclPlugin = new IntelFpgaOpenclPlugin();
-    discoverer.setResourceHanderPlugin(openclPlugin);
-    openclPlugin.initPlugin(conf);
-    openclPlugin.setInnerShellExecutor(mockPuginShell());
-    discoverer.setScriptRunner(s -> {
+    fpgaDiscoverer.setScriptRunner(s -> {
       return Optional.of(""); });
 
-    discoverer.initialize(conf);
-    discoverer.discover();
+    fpgaDiscoverer.initialize(conf);
+    fpgaDiscoverer.discover();
   }
 
   @Test
@@ -280,20 +245,14 @@ public class TestFpgaDiscoverer {
     expected.expect(ResourceHandlerException.class);
     expected.expectMessage("Unable to run external script");
 
-    Configuration conf = new Configuration(false);
     conf.set(YarnConfiguration.NM_FPGA_DEVICE_DISCOVERY_SCRIPT,
         "/dummy/script");
-    FpgaDiscoverer discoverer = FpgaDiscoverer.getInstance();
 
-    IntelFpgaOpenclPlugin openclPlugin = new IntelFpgaOpenclPlugin();
-    discoverer.setResourceHanderPlugin(openclPlugin);
-    openclPlugin.initPlugin(conf);
-    openclPlugin.setInnerShellExecutor(mockPuginShell());
-    discoverer.setScriptRunner(s -> {
+    fpgaDiscoverer.setScriptRunner(s -> {
       return Optional.empty(); });
 
-    discoverer.initialize(conf);
-    discoverer.discover();
+    fpgaDiscoverer.initialize(conf);
+    fpgaDiscoverer.discover();
   }
 
   @Test
@@ -302,17 +261,10 @@ public class TestFpgaDiscoverer {
     expected.expect(ResourceHandlerException.class);
     expected.expectMessage("Unable to run external script");
 
-    Configuration conf = new Configuration(false);
     conf.set(YarnConfiguration.NM_FPGA_DEVICE_DISCOVERY_SCRIPT, "");
-    FpgaDiscoverer discoverer = FpgaDiscoverer.getInstance();
 
-    IntelFpgaOpenclPlugin openclPlugin = new IntelFpgaOpenclPlugin();
-    discoverer.setResourceHanderPlugin(openclPlugin);
-    openclPlugin.initPlugin(conf);
-    openclPlugin.setInnerShellExecutor(mockPuginShell());
-
-    discoverer.initialize(conf);
-    discoverer.discover();
+    fpgaDiscoverer.initialize(conf);
+    fpgaDiscoverer.discover();
   }
 
   @Test
@@ -323,21 +275,14 @@ public class TestFpgaDiscoverer {
       expected.expect(ResourceHandlerException.class);
       expected.expectMessage("Unable to run external script");
 
-      Configuration conf = new Configuration(false);
       fakeScript = new File(getTestParentFolder() + "/fakeScript");
       touchFile(fakeScript);
       fakeScript.setExecutable(false);
       conf.set(YarnConfiguration.NM_FPGA_DEVICE_DISCOVERY_SCRIPT,
           fakeScript.getAbsolutePath());
-      FpgaDiscoverer discoverer = FpgaDiscoverer.getInstance();
-
-      IntelFpgaOpenclPlugin openclPlugin = new IntelFpgaOpenclPlugin();
-      discoverer.setResourceHanderPlugin(openclPlugin);
-      openclPlugin.initPlugin(conf);
-      openclPlugin.setInnerShellExecutor(mockPuginShell());
 
-      discoverer.initialize(conf);
-      discoverer.discover();
+      fpgaDiscoverer.initialize(conf);
+      fpgaDiscoverer.discover();
     } finally {
       fakeScript.delete();
     }