YARN-10507. Add the capability to fs2cs to write the converted placement rules inside capacity-scheduler.xml. Contributed by Peter Bacsko

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/fair/converter/FSConfigToCSConfigArgumentHandler.java

@@ -112,6 +112,9 @@ public class FSConfigToCSConfigArgumentHandler {
     ENABLE_ASYNC_SCHEDULER("enable asynchronous scheduler", "a", "enable-async-scheduler",
       "Enables the Asynchronous scheduler which decouples the CapacityScheduler" +
         " scheduling from Node Heartbeats.", false),
+    RULES_TO_FILE("rules to external file", "e", "rules-to-file",
+        "Generates the converted placement rules to an external JSON file " +
+        "called mapping-rules.json", false),
     HELP("help", "h", "help", "Displays the list of options", false);
 
     private final String name;
@@ -254,6 +257,13 @@ public class FSConfigToCSConfigArgumentHandler {
     checkDirectory(CliOption.OUTPUT_DIR, outputDir);
     checkOutputDirDoesNotContainXmls(yarnSiteXmlFile, outputDir);
 
+    // check mapping-rules.json if we intend to generate it
+    if (!cliParser.hasOption(CliOption.CONSOLE_MODE.shortSwitch) &&
+        cliParser.hasOption(CliOption.RULES_TO_FILE.shortSwitch)) {
+      checkFileNotInOutputDir(new File(outputDir),
+          FSConfigToCSConfigConverter.MAPPING_RULES_JSON);
+    }
+
     return FSConfigToCSConfigConverterParams.Builder.create()
         .withYarnSiteXmlConfig(yarnSiteXmlFile)
         .withFairSchedulerXmlConfig(fairSchedulerXmlFile)
@@ -263,6 +273,8 @@ public class FSConfigToCSConfigArgumentHandler {
         .withConsole(cliParser.hasOption(CliOption.CONSOLE_MODE.shortSwitch))
         .withOutputDirectory(outputDir)
         .withConvertPlacementRules(convertPlacementRules)
+        .withPlacementRulesToFile(
+            cliParser.hasOption(CliOption.RULES_TO_FILE.shortSwitch))
         .build();
   }
 

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/fair/converter/FSConfigToCSConfigConverter.java

@@ -17,13 +17,18 @@
 package org.apache.hadoop.yarn.server.resourcemanager.scheduler.fair.converter;
 
 import static org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.CapacitySchedulerConfiguration.PREFIX;
+import static org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.CapacitySchedulerConfiguration.MAPPING_RULE_FORMAT;
+import static org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.CapacitySchedulerConfiguration.MAPPING_RULE_JSON;
+import static org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.CapacitySchedulerConfiguration.MAPPING_RULE_FORMAT_JSON;
 import static org.apache.hadoop.yarn.server.resourcemanager.scheduler.fair.converter.FSQueueConverter.QUEUE_MAX_AM_SHARE_DISABLED;
 
+import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.FileNotFoundException;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.OutputStream;
+import java.nio.charset.StandardCharsets;
 import java.util.List;
 import java.util.Map;
 
@@ -55,6 +60,7 @@ import com.fasterxml.jackson.core.util.DefaultPrettyPrinter;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.databind.ObjectWriter;
 import org.apache.hadoop.thirdparty.com.google.common.annotations.VisibleForTesting;
+import com.fasterxml.jackson.core.JsonGenerator;
 
 /**
  * Converts Fair Scheduler configuration (site and fair-scheduler.xml)
@@ -64,13 +70,13 @@ import org.apache.hadoop.thirdparty.com.google.common.annotations.VisibleForTest
 public class FSConfigToCSConfigConverter {
   public static final Logger LOG = LoggerFactory.getLogger(
       FSConfigToCSConfigConverter.class.getName());
+  public static final String MAPPING_RULES_JSON =
+      "mapping-rules.json";
   private static final String YARN_SITE_XML = "yarn-site.xml";
   private static final String CAPACITY_SCHEDULER_XML =
       "capacity-scheduler.xml";
   private static final String FAIR_SCHEDULER_XML =
       "fair-scheduler.xml";
-  private static final String MAPPING_RULES_JSON =
-      "mapping-rules.json";
 
   public static final String WARNING_TEXT =
       "WARNING: This feature is experimental and not intended " +
@@ -99,6 +105,7 @@ public class FSConfigToCSConfigConverter {
   private boolean consoleMode = false;
   private boolean convertPlacementRules = true;
   private String outputDirectory;
+  private boolean rulesToFile;
 
   public FSConfigToCSConfigConverter(FSConfigToCSConfigRuleHandler
       ruleHandler, ConversionOptions conversionOptions) {
@@ -106,7 +113,6 @@ public class FSConfigToCSConfigConverter {
     this.conversionOptions = conversionOptions;
     this.yarnSiteOutputStream = System.out;
     this.capacitySchedulerOutputStream = System.out;
-    this.mappingRulesOutputStream = System.out;
     this.placementConverter = new QueuePlacementConverter();
   }
 
@@ -116,6 +122,7 @@ public class FSConfigToCSConfigConverter {
     this.clusterResource = getClusterResource(params);
     this.convertPlacementRules = params.isConvertPlacementRules();
     this.outputDirectory = params.getOutputDirectory();
+    this.rulesToFile = params.isPlacementRulesToFile();
     prepareOutputFiles(params.isConsole());
     loadConversionRules(params.getConversionRulesConfig());
     Configuration inputYarnSiteConfig = getInputYarnSiteConfig(params);
@@ -127,9 +134,9 @@ public class FSConfigToCSConfigConverter {
   private void prepareOutputFiles(boolean console)
       throws FileNotFoundException {
     if (console) {
-      LOG.info("Console mode is enabled, " + YARN_SITE_XML + " and" +
+      LOG.info("Console mode is enabled, {}, {} and {} will be only emitted " +
-          " " + CAPACITY_SCHEDULER_XML + " will be only emitted " +
+          "to the console!",
-          "to the console!");
+          YARN_SITE_XML, CAPACITY_SCHEDULER_XML, MAPPING_RULES_JSON);
       this.consoleMode = true;
       return;
     }
@@ -253,6 +260,10 @@ public class FSConfigToCSConfigConverter {
     convertYarnSiteXml(inputYarnSiteConfig);
     convertCapacitySchedulerXml(fs);
 
+    if (convertPlacementRules) {
+      performRuleConversion(fs);
+    }
+
     if (consoleMode) {
       System.out.println("======= " + CAPACITY_SCHEDULER_XML + " =======");
     }
@@ -263,10 +274,6 @@ public class FSConfigToCSConfigConverter {
       System.out.println("======= " + YARN_SITE_XML + " =======");
     }
     convertedYarnSiteConfig.writeXml(yarnSiteOutputStream);
-
-    if (convertPlacementRules) {
-      performRuleConversion(fs);
-    }
   }
 
   private void convertYarnSiteXml(Configuration inputYarnSiteConfig) {
@@ -313,28 +320,58 @@ public class FSConfigToCSConfigConverter {
         fs.getRMContext().getQueuePlacementManager();
 
     if (placementManager.getPlacementRules().size() > 0) {
-      if (!consoleMode) {
+      mappingRulesOutputStream = getOutputStreamForJson();
-        File mappingRulesFile = new File(outputDirectory,
-            MAPPING_RULES_JSON);
-        this.mappingRulesOutputStream =
-            new FileOutputStream(mappingRulesFile);
-      } else {
-        System.out.println("======= " + MAPPING_RULES_JSON + " =======");
-      }
 
       MappingRulesDescription desc =
           placementConverter.convertPlacementPolicy(placementManager,
               ruleHandler, capacitySchedulerConfig);
 
       ObjectMapper mapper = new ObjectMapper();
+      // close output stream if we write to a file, leave it open otherwise
+      if (!consoleMode && rulesToFile) {
+        mapper.configure(JsonGenerator.Feature.AUTO_CLOSE_TARGET, true);
+      } else {
+        mapper.configure(JsonGenerator.Feature.AUTO_CLOSE_TARGET, false);
+      }
       ObjectWriter writer = mapper.writer(new DefaultPrettyPrinter());
 
+      if (consoleMode && rulesToFile) {
+        System.out.println("======= " + MAPPING_RULES_JSON + " =======");
+      }
       writer.writeValue(mappingRulesOutputStream, desc);
+
+      capacitySchedulerConfig.set(MAPPING_RULE_FORMAT,
+          MAPPING_RULE_FORMAT_JSON);
+      if (!rulesToFile) {
+        String json =
+            ((ByteArrayOutputStream)mappingRulesOutputStream)
+            .toString(StandardCharsets.UTF_8.displayName());
+        capacitySchedulerConfig.set(MAPPING_RULE_JSON, json);
+      }
     } else {
       LOG.info("No rules to convert");
     }
   }
 
+  /*
+   * Console    RulesToFile   OutputStream
+   * true       true          System.out / PrintStream
+   * true       false         ByteArrayOutputStream
+   * false      true          FileOutputStream
+   * false      false         ByteArrayOutputStream
+   */
+  private OutputStream getOutputStreamForJson() throws FileNotFoundException {
+    if (consoleMode && rulesToFile) {
+      return System.out;
+    } else if (rulesToFile) {
+      File mappingRulesFile = new File(outputDirectory,
+          MAPPING_RULES_JSON);
+      return new FileOutputStream(mappingRulesFile);
+    } else {
+      return new ByteArrayOutputStream();
+    }
+  }
+
   private void emitDefaultQueueMaxParallelApplications() {
     if (queueMaxAppsDefault != Integer.MAX_VALUE) {
       capacitySchedulerConfig.set(
@@ -467,11 +504,6 @@ public class FSConfigToCSConfigConverter {
     this.placementConverter = converter;
   }
 
-  @VisibleForTesting
-  void setMappingRulesOutputStream(OutputStream outputStream) {
-    this.mappingRulesOutputStream = outputStream;
-  }
-
   @VisibleForTesting
   void setConsoleMode(boolean console) {
     this.consoleMode = console;

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/fair/converter/FSConfigToCSConfigConverterMain.java

@@ -16,6 +16,9 @@
 
 package org.apache.hadoop.yarn.server.resourcemanager.scheduler.fair.converter;
 
+import java.util.function.Consumer;
+
+import org.apache.hadoop.thirdparty.com.google.common.annotations.VisibleForTesting;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.slf4j.Marker;
@@ -25,12 +28,16 @@ import org.slf4j.MarkerFactory;
  * Main class that invokes the FS->CS converter.
  *
  */
-@SuppressWarnings("checkstyle:hideutilityclassconstructor")
+public final class FSConfigToCSConfigConverterMain {
-public class FSConfigToCSConfigConverterMain {
+  private FSConfigToCSConfigConverterMain() {
+    // no instances
+  }
+
   private static final Logger LOG =
       LoggerFactory.getLogger(FSConfigToCSConfigConverterMain.class);
   private static final Marker FATAL =
       MarkerFactory.getMarker("FATAL");
+  private static Consumer<Integer> exitFunction = System::exit;
 
   public static void main(String[] args) {
     try {
@@ -44,11 +51,16 @@ public class FSConfigToCSConfigConverterMain {
                 "see previous error messages for details!");
       }
 
-      System.exit(exitCode);
+      exitFunction.accept(exitCode);
     } catch (Throwable t) {
       LOG.error(FATAL,
           "Error while starting FS configuration conversion!", t);
-      System.exit(-1);
+      exitFunction.accept(-1);
     }
   }
+
+  @VisibleForTesting
+  static void setExit(Consumer<Integer> exitFunc) {
+    exitFunction = exitFunc;
+  }
 }

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/fair/converter/FSConfigToCSConfigConverterParams.java

@@ -28,7 +28,7 @@ public final class FSConfigToCSConfigConverterParams {
   private String clusterResource;
   private String outputDirectory;
   private boolean convertPlacementRules;
-
+  private boolean placementRulesToFile;
 
 
   private FSConfigToCSConfigConverterParams() {
@@ -63,6 +63,10 @@ public final class FSConfigToCSConfigConverterParams {
     return convertPlacementRules;
   }
 
+  public boolean isPlacementRulesToFile() {
+    return placementRulesToFile;
+  }
+
   @Override
   public String toString() {
     return "FSConfigToCSConfigConverterParams{" +
@@ -72,6 +76,7 @@ public final class FSConfigToCSConfigConverterParams {
         ", clusterResource='" + clusterResource + '\'' +
         ", console=" + console + '\'' +
         ", convertPlacementRules=" + convertPlacementRules +
+        ", placementRulesToFile=" + placementRulesToFile +
         '}';
   }
 
@@ -87,6 +92,7 @@ public final class FSConfigToCSConfigConverterParams {
     private String clusterResource;
     private String outputDirectory;
     private boolean convertPlacementRules;
+    private boolean placementRulesToFile;
 
     private Builder() {
     }
@@ -130,6 +136,11 @@ public final class FSConfigToCSConfigConverterParams {
       return this;
     }
 
+    public Builder withPlacementRulesToFile(boolean rulesToFile) {
+      this.placementRulesToFile = rulesToFile;
+      return this;
+    }
+
     public FSConfigToCSConfigConverterParams build() {
       FSConfigToCSConfigConverterParams params =
           new FSConfigToCSConfigConverterParams();
@@ -140,6 +151,7 @@ public final class FSConfigToCSConfigConverterParams {
       params.conversionRulesConfig = this.conversionRulesConfig;
       params.outputDirectory = this.outputDirectory;
       params.convertPlacementRules = this.convertPlacementRules;
+      params.placementRulesToFile = this.placementRulesToFile;
       return params;
     }
   }

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/fair/converter/VerificationException.java

@@ -28,4 +28,7 @@ public class VerificationException extends RuntimeException {
   public VerificationException(String message, Throwable cause) {
     super(message, cause);
   }
+
+  public VerificationException() {
+  }
 }

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/fair/converter/TestFSConfigToCSConfigArgumentHandler.java

@@ -19,7 +19,9 @@ package org.apache.hadoop.yarn.server.resourcemanager.scheduler.fair.converter;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
+import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.ArgumentMatchers.anyString;
+import static org.mockito.Mockito.doThrow;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.verifyZeroInteractions;
 
@@ -29,6 +31,7 @@ import java.util.Arrays;
 import java.util.List;
 
 import org.apache.commons.io.FileUtils;
+import org.apache.hadoop.thirdparty.com.google.common.collect.Lists;
 import org.apache.hadoop.yarn.conf.YarnConfiguration;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.QueueMetrics;
 import org.junit.After;
@@ -45,8 +48,6 @@ import org.mockito.junit.MockitoJUnitRunner;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-import org.apache.hadoop.thirdparty.com.google.common.collect.Lists;
-
 /**
  * Unit tests for FSConfigToCSConfigArgumentHandler.
  *
@@ -229,6 +230,28 @@ public class TestFSConfigToCSConfigArgumentHandler {
             "precondition error"));
   }
 
+  @Test
+  public void testVerificationException() throws Exception {
+    setupFSConfigConversionFiles(true);
+    ConversionOptions mockOptions = Mockito.mock(ConversionOptions.class);
+    FSConfigToCSConfigArgumentHandler argumentHandler =
+        new FSConfigToCSConfigArgumentHandler(mockOptions, mockValidator);
+    argumentHandler.setConverterSupplier(this::getMockConverter);
+
+    String[] args = getArgumentsAsArrayWithDefaults("-f",
+        FSConfigConverterTestCommons.FS_ALLOC_FILE,
+        "-r", FSConfigConverterTestCommons.CONVERSION_RULES_FILE);
+
+    doThrow(new VerificationException("test", new Exception("test")))
+      .when(mockConverter)
+        .convert(any(FSConfigToCSConfigConverterParams.class));
+
+    argumentHandler.parseAndConvert(args);
+
+    verify(mockOptions).handleVerificationFailure(any(Exception.class),
+        any(String.class));
+  }
+
   @Test
   public void testFairSchedulerXmlIsNotDefinedIfItsDefinedInYarnSiteXml()
       throws Exception {
@@ -534,7 +557,8 @@ public class TestFSConfigToCSConfigArgumentHandler {
 
       String[] args = new String[] {
           "-y", FSConfigConverterTestCommons.YARN_SITE_XML,
-          "-o", FSConfigConverterTestCommons.OUTPUT_DIR};
+          "-o", FSConfigConverterTestCommons.OUTPUT_DIR,
+          "-e"};
 
       int retVal = argumentHandler.parseAndConvert(args);
       assertEquals("Return value", -1, retVal);
@@ -564,6 +588,13 @@ public class TestFSConfigToCSConfigArgumentHandler {
         YarnConfiguration.CS_CONFIGURATION_FILE);
   }
 
+  @Test
+  public void testMappingRulesJsonExistsInOutputFolder()
+      throws Exception {
+    testFileExistsInOutputFolder(
+        "mapping-rules.json");
+  }
+
   @Test
   public void testPlacementRulesConversionEnabled() throws Exception {
     testPlacementRuleConversion(true);

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/fair/converter/TestFSConfigToCSConfigConverter.java

@@ -36,7 +36,6 @@ import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.verifyZeroInteractions;
 
 import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.IOException;
 import java.util.Map;
@@ -463,6 +462,7 @@ public class TestFSConfigToCSConfigConverter {
     FSConfigToCSConfigConverterParams params = createDefaultParamsBuilder()
         .withClusterResource(CLUSTER_RESOURCE_STRING)
         .withConvertPlacementRules(true)
+        .withPlacementRulesToFile(true)
         .build();
 
     converter.convert(params);
@@ -612,17 +612,17 @@ public class TestFSConfigToCSConfigConverter {
     config.setBoolean(FairSchedulerConfiguration.USER_AS_DEFAULT_QUEUE,
         true);
 
-    ByteArrayOutputStream jsonOutStream = new ByteArrayOutputStream();
     converter.setConvertPlacementRules(true);
-    converter.setMappingRulesOutputStream(jsonOutStream);
     converter.setConsoleMode(true);
     converter.convert(config);
+    String json = converter.getCapacitySchedulerConfig()
+        .get(CapacitySchedulerConfiguration.MAPPING_RULE_JSON);
 
     MappingRulesDescription description =
         new ObjectMapper()
           .reader()
           .forType(MappingRulesDescription.class)
-          .readValue(jsonOutStream.toByteArray());
+          .readValue(json);
 
     if (hasPlacementRules) {
       // fs.xml defines 5 rules

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/fair/converter/TestFSConfigToCSConfigConverterMain.java

@@ -21,17 +21,17 @@ import static org.apache.hadoop.yarn.server.resourcemanager.scheduler.fair.conve
 import static org.apache.hadoop.yarn.server.resourcemanager.scheduler.fair.converter.FSConfigConverterTestCommons.OUTPUT_DIR;
 import static org.apache.hadoop.yarn.server.resourcemanager.scheduler.fair.converter.FSConfigConverterTestCommons.YARN_SITE_XML;
 import static org.apache.hadoop.yarn.server.resourcemanager.scheduler.fair.converter.FSConfigConverterTestCommons.setupFSConfigConversionFiles;
+import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertTrue;
 
 import java.io.File;
 import java.io.IOException;
+import java.util.function.Consumer;
 
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.QueueMetrics;
 import org.junit.After;
 import org.junit.Before;
-import org.junit.Rule;
 import org.junit.Test;
-import org.junit.contrib.java.lang.system.ExpectedSystemExit;
 
 
 /**
@@ -40,19 +40,20 @@ import org.junit.contrib.java.lang.system.ExpectedSystemExit;
  */
 public class TestFSConfigToCSConfigConverterMain {
   private FSConfigConverterTestCommons converterTestCommons;
-
+  private ExitFunc exitFunc;
-  @Rule
-  public final ExpectedSystemExit exit = ExpectedSystemExit.none();
 
   @Before
   public void setUp() throws Exception {
+    exitFunc = new ExitFunc();
     converterTestCommons = new FSConfigConverterTestCommons();
     converterTestCommons.setUp();
+    FSConfigToCSConfigConverterMain.setExit(exitFunc);
   }
 
   @After
   public void tearDown() throws Exception {
     QueueMetrics.clearQueueMetrics();
+    FSConfigToCSConfigConverterMain.setExit(System::exit);
     converterTestCommons.tearDown();
   }
 
@@ -68,7 +69,6 @@ public class TestFSConfigToCSConfigConverterMain {
   public void testConvertFSConfigurationDefaults()
       throws Exception {
     setupFSConfigConversionFiles();
-    exit.expectSystemExitWithStatus(0);
 
     FSConfigToCSConfigConverterMain.main(new String[] {
         "-o", OUTPUT_DIR,
@@ -83,17 +83,18 @@ public class TestFSConfigToCSConfigConverterMain {
 
     assertTrue("capacity-scheduler.xml was not generated", csConfigExists);
     assertTrue("yarn-site.xml was not generated", yarnSiteConfigExists);
+    assertEquals("Exit code", 0, exitFunc.exitCode);
   }
 
   @Test
   public void testConvertFSConfigurationWithConsoleParam()
       throws Exception {
     setupFSConfigConversionFiles();
-    exit.expectSystemExitWithStatus(0);
 
     FSConfigToCSConfigConverterMain.main(new String[] {
         "-p",
         "-m",
+        "-e",
         "-y", YARN_SITE_XML,
         "-f", FS_ALLOC_FILE,
         "-r", CONVERSION_RULES_FILE});
@@ -105,35 +106,42 @@ public class TestFSConfigToCSConfigConverterMain {
         stdout.contains("======= capacity-scheduler.xml ======="));
     assertTrue("Stdout doesn't contain mapping-rules.json",
         stdout.contains("======= mapping-rules.json ======="));
+    assertEquals("Exit code", 0, exitFunc.exitCode);
   }
 
   @Test
   public void testShortHelpSwitch() {
-    exit.expectSystemExitWithStatus(0);
-
     FSConfigToCSConfigConverterMain.main(new String[] {"-h"});
 
     verifyHelpText();
+    assertEquals("Exit code", 0, exitFunc.exitCode);
   }
 
   @Test
   public void testLongHelpSwitch() {
-    exit.expectSystemExitWithStatus(0);
-
     FSConfigToCSConfigConverterMain.main(new String[] {"--help"});
 
     verifyHelpText();
+    assertEquals("Exit code", 0, exitFunc.exitCode);
+  }
+
+  @Test
+  public void testHelpDisplayedWithoutArgs() {
+    FSConfigToCSConfigConverterMain.main(new String[] {});
+
+    verifyHelpText();
+    assertEquals("Exit code", 0, exitFunc.exitCode);
   }
 
   @Test
   public void testConvertFSConfigurationWithLongSwitches()
       throws IOException {
-    exit.expectSystemExitWithStatus(0);
     setupFSConfigConversionFiles();
 
     FSConfigToCSConfigConverterMain.main(new String[] {
         "--print",
         "--convert-placement-rules",
+        "--rules-to-file",
         "--yarnsiteconfig", YARN_SITE_XML,
         "--fsconfig", FS_ALLOC_FILE,
         "--rulesconfig", CONVERSION_RULES_FILE});
@@ -145,6 +153,16 @@ public class TestFSConfigToCSConfigConverterMain {
         stdout.contains("======= capacity-scheduler.xml ======="));
     assertTrue("Stdout doesn't contain mapping-rules.json",
         stdout.contains("======= mapping-rules.json ======="));
+    assertEquals("Exit code", 0, exitFunc.exitCode);
+  }
+
+  @Test
+  public void testNegativeReturnValueOnError() {
+    FSConfigToCSConfigConverterMain.main(new String[] {
+        "--print",
+        "--yarnsiteconfig"});
+
+    assertEquals("Exit code", -1, exitFunc.exitCode);
   }
 
   private void verifyHelpText() {
@@ -152,4 +170,14 @@ public class TestFSConfigToCSConfigConverterMain {
     assertTrue("Help was not displayed",
         stdout.contains("General options are:"));
   }
+
+  @SuppressWarnings("checkstyle:visibilitymodifier")
+  class ExitFunc implements Consumer<Integer> {
+    int exitCode;
+
+    @Override
+    public void accept(Integer t) {
+      this.exitCode = t.intValue();
+    }
+  }
 }