Cli: Simplify test terminals

This commit simplifies and consolidates the two different
implementations of terminals used in tests. There is now a single
MockTerminal which captures output, and allows accessing as one large
string (with unix style \n as newlines), as well as configuring
input.

core/src/main/java/org/elasticsearch/bootstrap/BootstrapCLIParser.java

@@ -26,8 +26,8 @@ import org.elasticsearch.common.Strings;
 import org.elasticsearch.common.SuppressForbidden;
 import org.elasticsearch.common.cli.CliTool;
 import org.elasticsearch.common.cli.CliToolConfig;
-import org.elasticsearch.common.cli.Terminal;
 import org.elasticsearch.common.cli.UserError;
+import org.elasticsearch.common.cli.Terminal;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.env.Environment;
 import org.elasticsearch.monitor.jvm.JvmInfo;
@@ -37,7 +37,6 @@ import java.util.Iterator;
 import java.util.Locale;
 import java.util.Map;
 import java.util.Properties;
-import java.util.Set;
 
 import static org.elasticsearch.common.cli.CliToolConfig.Builder.cmd;
 import static org.elasticsearch.common.cli.CliToolConfig.Builder.optionBuilder;

core/src/main/java/org/elasticsearch/common/cli/Terminal.java

@@ -23,6 +23,7 @@ import java.io.BufferedReader;
 import java.io.Console;
 import java.io.IOException;
 import java.io.InputStreamReader;
+import java.io.PrintWriter;
 import java.nio.charset.Charset;
 
 import org.elasticsearch.common.SuppressForbidden;
@@ -52,6 +53,13 @@ public abstract class Terminal {
     /** The current verbosity for the terminal, defaulting to {@link Verbosity#NORMAL}. */
     private Verbosity verbosity = Verbosity.NORMAL;
 
+    /** The newline used when calling println. */
+    private final String lineSeparator;
+
+    protected Terminal(String lineSeparator) {
+        this.lineSeparator = lineSeparator;
+    }
+
     /** Sets the verbosity of the terminal. */
     void setVerbosity(Verbosity verbosity) {
         this.verbosity = verbosity;
@@ -63,8 +71,8 @@ public abstract class Terminal {
     /** Reads password text from the terminal input. See {@link Console#readPassword()}}. */
     public abstract char[] readSecret(String prompt);
 
-    /** Print a message directly to the terminal. */
+    /** Returns a Writer which can be used to write to the terminal directly. */
-    protected abstract void doPrint(String msg);
+    public abstract PrintWriter getWriter();
 
     /** Prints a line to the terminal at {@link Verbosity#NORMAL} verbosity level. */
     public final void println(String msg) {
@@ -74,7 +82,8 @@ public abstract class Terminal {
     /** Prints a line to the terminal at {@code verbosity} level. */
     public final void println(Verbosity verbosity, String msg) {
         if (this.verbosity.ordinal() >= verbosity.ordinal()) {
-            doPrint(msg + System.lineSeparator());
+            getWriter().print(msg + lineSeparator);
+            getWriter().flush();
         }
     }
 
@@ -82,14 +91,17 @@ public abstract class Terminal {
 
         private static final Console console = System.console();
 
+        ConsoleTerminal() {
+            super(System.lineSeparator());
+        }
+
         static boolean isSupported() {
             return console != null;
         }
 
         @Override
-        public void doPrint(String msg) {
+        public PrintWriter getWriter() {
-            console.printf("%s", msg);
+            return console.writer();
-            console.flush();
         }
 
         @Override
@@ -105,16 +117,25 @@ public abstract class Terminal {
 
     private static class SystemTerminal extends Terminal {
 
+        private final PrintWriter writer = newWriter();
+
+        SystemTerminal() {
+            super(System.lineSeparator());
+        }
+
+        @SuppressForbidden(reason = "Writer for System.out")
+        private static PrintWriter newWriter() {
+            return new PrintWriter(System.out);
+        }
+
         @Override
-        @SuppressForbidden(reason = "System#out")
+        public PrintWriter getWriter() {
-        public void doPrint(String msg) {
+            return writer;
-            System.out.print(msg);
-            System.out.flush();
         }
 
         @Override
         public String readText(String text) {
-            doPrint(text);
+            getWriter().print(text);
             BufferedReader reader = new BufferedReader(new InputStreamReader(System.in, Charset.defaultCharset()));
             try {
                 return reader.readLine();

core/src/test/java/org/elasticsearch/common/cli/TerminalTests.java

@@ -19,41 +19,40 @@
 
 package org.elasticsearch.common.cli;
 
-import static org.hamcrest.Matchers.hasItem;
-import static org.hamcrest.Matchers.hasSize;
-
 public class TerminalTests extends CliToolTestCase {
     public void testVerbosity() throws Exception {
-        CaptureOutputTerminal terminal = new CaptureOutputTerminal(Terminal.Verbosity.SILENT);
+        MockTerminal terminal = new MockTerminal();
+        terminal.setVerbosity(Terminal.Verbosity.SILENT);
         assertPrinted(terminal, Terminal.Verbosity.SILENT, "text");
         assertNotPrinted(terminal, Terminal.Verbosity.NORMAL, "text");
         assertNotPrinted(terminal, Terminal.Verbosity.VERBOSE, "text");
 
-        terminal = new CaptureOutputTerminal(Terminal.Verbosity.NORMAL);
+        terminal = new MockTerminal();
         assertPrinted(terminal, Terminal.Verbosity.SILENT, "text");
         assertPrinted(terminal, Terminal.Verbosity.NORMAL, "text");
         assertNotPrinted(terminal, Terminal.Verbosity.VERBOSE, "text");
 
-        terminal = new CaptureOutputTerminal(Terminal.Verbosity.VERBOSE);
+        terminal = new MockTerminal();
+        terminal.setVerbosity(Terminal.Verbosity.VERBOSE);
         assertPrinted(terminal, Terminal.Verbosity.SILENT, "text");
         assertPrinted(terminal, Terminal.Verbosity.NORMAL, "text");
         assertPrinted(terminal, Terminal.Verbosity.VERBOSE, "text");
     }
 
     public void testEscaping() throws Exception {
-        CaptureOutputTerminal terminal = new CaptureOutputTerminal(Terminal.Verbosity.NORMAL);
+        MockTerminal terminal = new MockTerminal();
         assertPrinted(terminal, Terminal.Verbosity.NORMAL, "This message contains percent like %20n");
     }
 
-    private void assertPrinted(CaptureOutputTerminal logTerminal, Terminal.Verbosity verbosity, String text) {
+    private void assertPrinted(MockTerminal logTerminal, Terminal.Verbosity verbosity, String text) throws Exception {
         logTerminal.println(verbosity, text);
-        assertEquals(1, logTerminal.getTerminalOutput().size());
+        assertTrue(logTerminal.getOutput().contains(text));
-        assertTrue(logTerminal.getTerminalOutput().get(0).contains(text));
+        logTerminal.resetOutput();
-        logTerminal.terminalOutput.clear();
     }
 
-    private void assertNotPrinted(CaptureOutputTerminal logTerminal, Terminal.Verbosity verbosity, String text) {
+    private void assertNotPrinted(MockTerminal logTerminal, Terminal.Verbosity verbosity, String text) throws Exception {
         logTerminal.println(verbosity, text);
-        assertThat(logTerminal.getTerminalOutput(), hasSize(0));
+        String output = logTerminal.getOutput();
+        assertTrue(output, output.isEmpty());
     }
 }

core/src/test/java/org/elasticsearch/common/logging/LoggingConfigurationTests.java

@@ -19,21 +19,21 @@
 
 package org.elasticsearch.common.logging;
 
-import org.apache.log4j.Appender;
-import org.apache.log4j.Logger;
-import org.elasticsearch.common.cli.CliToolTestCase;
-import org.elasticsearch.common.settings.Settings;
-import org.elasticsearch.env.Environment;
-import org.elasticsearch.node.internal.InternalSettingsPreparer;
-import org.elasticsearch.test.ESTestCase;
-import org.junit.Before;
-
 import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.StandardOpenOption;
 import java.util.Arrays;
 
+import org.apache.log4j.Appender;
+import org.apache.log4j.Logger;
+import org.elasticsearch.common.cli.MockTerminal;
+import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.env.Environment;
+import org.elasticsearch.node.internal.InternalSettingsPreparer;
+import org.elasticsearch.test.ESTestCase;
+import org.junit.Before;
+
 import static org.hamcrest.Matchers.is;
 import static org.hamcrest.Matchers.notNullValue;
 import static org.hamcrest.Matchers.nullValue;
@@ -162,7 +162,7 @@ public class LoggingConfigurationTests extends ESTestCase {
                         .put("appender.console.type", "console")
                         .put("appender.console.layout.type", "consolePattern")
                         .put("appender.console.layout.conversionPattern", "[%d{ISO8601}][%-5p][%-25c] %m%n")
-                        .build(), new CliToolTestCase.MockTerminal());
+                        .build(), new MockTerminal());
         LogConfigurator.configure(environment.settings(), true);
         // args should overwrite whatever is in the config
         ESLogger esLogger = ESLoggerFactory.getLogger("test_resolve_order");
@@ -187,7 +187,7 @@ public class LoggingConfigurationTests extends ESTestCase {
                 Settings.builder()
                         .put(Environment.PATH_CONF_SETTING.getKey(), tmpDir.toAbsolutePath())
                         .put(Environment.PATH_HOME_SETTING.getKey(), createTempDir().toString())
-                        .build(), new CliToolTestCase.MockTerminal());
+                        .build(), new MockTerminal());
         LogConfigurator.configure(environment.settings(), false);
         ESLogger esLogger = ESLoggerFactory.getLogger("test_config_not_read");
 

core/src/test/java/org/elasticsearch/node/internal/InternalSettingsPreparerTests.java

@@ -19,9 +19,13 @@
 
 package org.elasticsearch.node.internal;
 
+import java.io.IOException;
+import java.io.InputStream;
+import java.nio.file.Files;
+import java.nio.file.Path;
+
+import org.elasticsearch.common.cli.MockTerminal;
 import org.elasticsearch.cluster.ClusterName;
-import org.elasticsearch.common.cli.CliToolTestCase;
-import org.elasticsearch.common.cli.Terminal;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.settings.SettingsException;
 import org.elasticsearch.env.Environment;
@@ -29,17 +33,9 @@ import org.elasticsearch.test.ESTestCase;
 import org.junit.After;
 import org.junit.Before;
 
-import java.io.IOException;
-import java.io.InputStream;
-import java.nio.file.Files;
-import java.nio.file.Path;
-import java.util.ArrayList;
-import java.util.List;
-
 import static org.elasticsearch.common.settings.Settings.settingsBuilder;
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.equalTo;
-import static org.hamcrest.Matchers.is;
 
 public class InternalSettingsPreparerTests extends ESTestCase {
 
@@ -81,17 +77,9 @@ public class InternalSettingsPreparerTests extends ESTestCase {
     }
 
     public void testReplacePromptPlaceholders() {
-        final Terminal terminal = new CliToolTestCase.MockTerminal() {
+        MockTerminal terminal = new MockTerminal();
-            @Override
+        terminal.addTextInput("text");
-            public char[] readSecret(String message) {
+        terminal.addSecretInput("replaced");
-                return "replaced".toCharArray();
-            }
-
-            @Override
-            public String readText(String message) {
-                return "text";
-            }
-        };
 
         Settings.Builder builder = settingsBuilder()
                 .put(baseEnvSettings)

core/src/test/java/org/elasticsearch/plugins/PluginCliTests.java

@@ -20,6 +20,7 @@
 package org.elasticsearch.plugins;
 
 import org.elasticsearch.common.cli.CliToolTestCase;
+import org.elasticsearch.common.cli.MockTerminal;
 
 import static org.elasticsearch.common.cli.CliTool.ExitStatus.OK_AND_EXIT;
 import static org.hamcrest.Matchers.containsString;
@@ -28,22 +29,22 @@ import static org.hamcrest.Matchers.is;
 
 public class PluginCliTests extends CliToolTestCase {
     public void testHelpWorks() throws Exception {
-        CliToolTestCase.CaptureOutputTerminal terminal = new CliToolTestCase.CaptureOutputTerminal();
+        MockTerminal terminal = new MockTerminal();
         assertThat(new PluginCli(terminal).execute(args("--help")), is(OK_AND_EXIT));
         assertTerminalOutputContainsHelpFile(terminal, "/org/elasticsearch/plugins/plugin.help");
 
-        terminal.getTerminalOutput().clear();
+        terminal.resetOutput();
         assertThat(new PluginCli(terminal).execute(args("install -h")), is(OK_AND_EXIT));
         assertTerminalOutputContainsHelpFile(terminal, "/org/elasticsearch/plugins/plugin-install.help");
         for (String plugin : InstallPluginCommand.OFFICIAL_PLUGINS) {
-            assertThat(terminal.getTerminalOutput(), hasItem(containsString(plugin)));
+            assertThat(terminal.getOutput(), containsString(plugin));
         }
 
-        terminal.getTerminalOutput().clear();
+        terminal.resetOutput();
         assertThat(new PluginCli(terminal).execute(args("remove --help")), is(OK_AND_EXIT));
         assertTerminalOutputContainsHelpFile(terminal, "/org/elasticsearch/plugins/plugin-remove.help");
 
-        terminal.getTerminalOutput().clear();
+        terminal.resetOutput();
         assertThat(new PluginCli(terminal).execute(args("list -h")), is(OK_AND_EXIT));
         assertTerminalOutputContainsHelpFile(terminal, "/org/elasticsearch/plugins/plugin-list.help");
     }

qa/evil-tests/src/test/java/org/elasticsearch/bootstrap/BootstrapCliParserTests.java

@@ -24,10 +24,10 @@ import org.elasticsearch.Version;
 import org.elasticsearch.common.SuppressForbidden;
 import org.elasticsearch.common.cli.CliTool.ExitStatus;
 import org.elasticsearch.common.cli.CliToolTestCase;
+import org.elasticsearch.common.cli.MockTerminal;
 import org.elasticsearch.common.cli.UserError;
 import org.elasticsearch.common.collect.Tuple;
 import org.elasticsearch.monitor.jvm.JvmInfo;
-import org.hamcrest.Matcher;
 import org.junit.After;
 import org.junit.Before;
 
@@ -37,7 +37,6 @@ import java.util.HashMap;
 import java.util.List;
 import java.util.Locale;
 import java.util.Map;
-import java.util.Properties;
 
 import static org.elasticsearch.common.cli.CliTool.ExitStatus.OK;
 import static org.elasticsearch.common.cli.CliTool.ExitStatus.OK_AND_EXIT;
@@ -50,7 +49,7 @@ import static org.hamcrest.Matchers.nullValue;
 @SuppressForbidden(reason = "modifies system properties intentionally")
 public class BootstrapCliParserTests extends CliToolTestCase {
 
-    private CaptureOutputTerminal terminal = new CaptureOutputTerminal();
+    private MockTerminal terminal = new MockTerminal();
     private List<String> propertiesToClear = new ArrayList<>();
     private Map<Object, Object> properties;
 
@@ -73,10 +72,11 @@ public class BootstrapCliParserTests extends CliToolTestCase {
         ExitStatus status = parser.execute(args("version"));
         assertStatus(status, OK_AND_EXIT);
 
-        assertThatTerminalOutput(containsString(Version.CURRENT.toString()));
+        String output = terminal.getOutput();
-        assertThatTerminalOutput(containsString(Build.CURRENT.shortHash()));
+        assertTrue(output, output.contains(Version.CURRENT.toString()));
-        assertThatTerminalOutput(containsString(Build.CURRENT.date()));
+        assertTrue(output, output.contains(Build.CURRENT.shortHash()));
-        assertThatTerminalOutput(containsString(JvmInfo.jvmInfo().version()));
+        assertTrue(output, output.contains(Build.CURRENT.date()));
+        assertTrue(output, output.contains(JvmInfo.jvmInfo().version()));
     }
 
     public void testThatVersionIsReturnedAsStartParameter() throws Exception {
@@ -84,20 +84,22 @@ public class BootstrapCliParserTests extends CliToolTestCase {
         ExitStatus status = parser.execute(args("start -V"));
         assertStatus(status, OK_AND_EXIT);
 
-        assertThatTerminalOutput(containsString(Version.CURRENT.toString()));
+        String output = terminal.getOutput();
-        assertThatTerminalOutput(containsString(Build.CURRENT.shortHash()));
+        assertTrue(output, output.contains(Version.CURRENT.toString()));
-        assertThatTerminalOutput(containsString(Build.CURRENT.date()));
+        assertTrue(output, output.contains(Build.CURRENT.shortHash()));
-        assertThatTerminalOutput(containsString(JvmInfo.jvmInfo().version()));
+        assertTrue(output, output.contains(Build.CURRENT.date()));
+        assertTrue(output, output.contains(JvmInfo.jvmInfo().version()));
 
-        CaptureOutputTerminal terminal = new CaptureOutputTerminal();
+        terminal.resetOutput();
         parser = new BootstrapCLIParser(terminal);
         status = parser.execute(args("start --version"));
         assertStatus(status, OK_AND_EXIT);
 
-        assertThatTerminalOutput(containsString(Version.CURRENT.toString()));
+        output = terminal.getOutput();
-        assertThatTerminalOutput(containsString(Build.CURRENT.shortHash()));
+        assertTrue(output, output.contains(Version.CURRENT.toString()));
-        assertThatTerminalOutput(containsString(Build.CURRENT.date()));
+        assertTrue(output, output.contains(Build.CURRENT.shortHash()));
-        assertThatTerminalOutput(containsString(JvmInfo.jvmInfo().version()));
+        assertTrue(output, output.contains(Build.CURRENT.date()));
+        assertTrue(output, output.contains(JvmInfo.jvmInfo().version()));
     }
 
     public void testThatPidFileCanBeConfigured() throws Exception {
@@ -173,11 +175,14 @@ public class BootstrapCliParserTests extends CliToolTestCase {
 
         ExitStatus status = parser.execute(args("start --network.host"));
         assertStatus(status, USAGE);
-        assertThatTerminalOutput(containsString("Parameter [network.host] needs value"));
+        String output = terminal.getOutput();
+        assertTrue(output, output.contains("Parameter [network.host] needs value"));
 
+        terminal.resetOutput();
         status = parser.execute(args("start --network.host --foo"));
         assertStatus(status, USAGE);
-        assertThatTerminalOutput(containsString("Parameter [network.host] needs value"));
+        output = terminal.getOutput();
+        assertTrue(output, output.contains("Parameter [network.host] needs value"));
     }
 
     public void testParsingErrors() throws Exception {
@@ -186,28 +191,32 @@ public class BootstrapCliParserTests extends CliToolTestCase {
         // unknown params
         ExitStatus status = parser.execute(args("version --unknown-param /tmp/pid"));
         assertStatus(status, USAGE);
-        assertThatTerminalOutput(containsString("Unrecognized option: --unknown-param"));
+        String output = terminal.getOutput();
+        assertTrue(output, output.contains("Unrecognized option: --unknown-param"));
 
         // single dash in extra params
-        terminal = new CaptureOutputTerminal();
+        terminal.resetOutput();
         parser = new BootstrapCLIParser(terminal);
         status = parser.execute(args("start -network.host 127.0.0.1"));
         assertStatus(status, USAGE);
-        assertThatTerminalOutput(containsString("Parameter [-network.host]does not start with --"));
+        output = terminal.getOutput();
+        assertTrue(output, output.contains("Parameter [-network.host]does not start with --"));
 
         // never ended parameter
-        terminal = new CaptureOutputTerminal();
+        terminal = new MockTerminal();
         parser = new BootstrapCLIParser(terminal);
         status = parser.execute(args("start --network.host"));
         assertStatus(status, USAGE);
-        assertThatTerminalOutput(containsString("Parameter [network.host] needs value"));
+        output = terminal.getOutput();
+        assertTrue(output, output.contains("Parameter [network.host] needs value"));
 
         // free floating value
-        terminal = new CaptureOutputTerminal();
+        terminal = new MockTerminal();
         parser = new BootstrapCLIParser(terminal);
         status = parser.execute(args("start 127.0.0.1"));
         assertStatus(status, USAGE);
-        assertThatTerminalOutput(containsString("Parameter [127.0.0.1]does not start with --"));
+        output = terminal.getOutput();
+        assertTrue(output, output.contains("Parameter [127.0.0.1]does not start with --"));
     }
 
     public void testHelpWorks() throws Exception {
@@ -220,10 +229,11 @@ public class BootstrapCliParserTests extends CliToolTestCase {
         tuples.add(new Tuple<>("-h", "elasticsearch.help"));
 
         for (Tuple<String, String> tuple : tuples) {
-            terminal = new CaptureOutputTerminal();
+            terminal.resetOutput();
             BootstrapCLIParser parser = new BootstrapCLIParser(terminal);
             ExitStatus status = parser.execute(args(tuple.v1()));
             assertStatus(status, OK_AND_EXIT);
+            // nocommit
             assertTerminalOutputContainsHelpFile(terminal, "/org/elasticsearch/bootstrap/" + tuple.v2());
         }
     }
@@ -253,16 +263,12 @@ public class BootstrapCliParserTests extends CliToolTestCase {
         propertiesToClear.addAll(Arrays.asList(systemProperties));
     }
 
-    private void assertSystemProperty(String name, String expectedValue) {
+    private void assertSystemProperty(String name, String expectedValue) throws Exception {
-        String msg = String.format(Locale.ROOT, "Expected property %s to be %s, terminal output was %s", name, expectedValue, terminal.getTerminalOutput());
+        String msg = String.format(Locale.ROOT, "Expected property %s to be %s, terminal output was %s", name, expectedValue, terminal.getOutput());
         assertThat(msg, System.getProperty(name), is(expectedValue));
     }
 
-    private void assertStatus(ExitStatus status, ExitStatus expectedStatus) {
+    private void assertStatus(ExitStatus status, ExitStatus expectedStatus) throws Exception {
-        assertThat(String.format(Locale.ROOT, "Expected status to be [%s], but was [%s], terminal output was %s", expectedStatus, status, terminal.getTerminalOutput()), status, is(expectedStatus));
+        assertThat(String.format(Locale.ROOT, "Expected status to be [%s], but was [%s], terminal output was %s", expectedStatus, status, terminal.getOutput()), status, is(expectedStatus));
-    }
-
-    private void assertThatTerminalOutput(Matcher<String> matcher) {
-        assertThat(terminal.getTerminalOutput(), hasItem(matcher));
     }
 }

qa/evil-tests/src/test/java/org/elasticsearch/common/cli/CheckFileCommandTests.java

@@ -49,7 +49,7 @@ import static org.hamcrest.Matchers.is;
  */
 public class CheckFileCommandTests extends ESTestCase {
 
-    private CliToolTestCase.CaptureOutputTerminal captureOutputTerminal = new CliToolTestCase.CaptureOutputTerminal();
+    private MockTerminal captureOutputTerminal = new MockTerminal();
 
     private Configuration jimFsConfiguration = Configuration.unix().toBuilder().setAttributeViews("basic", "owner", "posix", "unix").build();
     private Configuration jimFsConfigurationWithoutPermissions = randomBoolean() ? Configuration.unix().toBuilder().setAttributeViews("basic").build() : Configuration.windows();
@@ -60,62 +60,62 @@ public class CheckFileCommandTests extends ESTestCase {
 
     public void testThatCommandLogsErrorMessageOnFail() throws Exception {
         executeCommand(jimFsConfiguration, new PermissionCheckFileCommand(createTempDir(), captureOutputTerminal, Mode.CHANGE));
-        assertThat(captureOutputTerminal.getTerminalOutput(), hasItem(containsString("Please ensure that the user account running Elasticsearch has read access to this file")));
+        assertThat(captureOutputTerminal.getOutput(), containsString("Please ensure that the user account running Elasticsearch has read access to this file"));
     }
 
     public void testThatCommandLogsNothingWhenPermissionRemains() throws Exception {
         executeCommand(jimFsConfiguration, new PermissionCheckFileCommand(createTempDir(), captureOutputTerminal, Mode.KEEP));
-        assertThat(captureOutputTerminal.getTerminalOutput(), hasSize(0));
+        assertTrue(captureOutputTerminal.getOutput().isEmpty());
     }
 
     public void testThatCommandLogsNothingWhenDisabled() throws Exception {
         executeCommand(jimFsConfiguration, new PermissionCheckFileCommand(createTempDir(), captureOutputTerminal, Mode.DISABLED));
-        assertThat(captureOutputTerminal.getTerminalOutput(), hasSize(0));
+        assertTrue(captureOutputTerminal.getOutput().isEmpty());
     }
 
     public void testThatCommandLogsNothingIfFilesystemDoesNotSupportPermissions() throws Exception {
         executeCommand(jimFsConfigurationWithoutPermissions, new PermissionCheckFileCommand(createTempDir(), captureOutputTerminal, Mode.DISABLED));
-        assertThat(captureOutputTerminal.getTerminalOutput(), hasSize(0));
+        assertTrue(captureOutputTerminal.getOutput().isEmpty());
     }
 
     public void testThatCommandLogsOwnerChange() throws Exception {
         executeCommand(jimFsConfiguration, new OwnerCheckFileCommand(createTempDir(), captureOutputTerminal, Mode.CHANGE));
-        assertThat(captureOutputTerminal.getTerminalOutput(), hasItem(allOf(containsString("Owner of file ["), containsString("] used to be ["), containsString("], but now is ["))));
+        assertThat(captureOutputTerminal.getOutput(), allOf(containsString("Owner of file ["), containsString("] used to be ["), containsString("], but now is [")));
     }
 
     public void testThatCommandLogsNothingIfOwnerRemainsSame() throws Exception {
         executeCommand(jimFsConfiguration, new OwnerCheckFileCommand(createTempDir(), captureOutputTerminal, Mode.KEEP));
-        assertThat(captureOutputTerminal.getTerminalOutput(), hasSize(0));
+        assertTrue(captureOutputTerminal.getOutput().isEmpty());
     }
 
     public void testThatCommandLogsNothingIfOwnerIsDisabled() throws Exception {
         executeCommand(jimFsConfiguration, new OwnerCheckFileCommand(createTempDir(), captureOutputTerminal, Mode.DISABLED));
-        assertThat(captureOutputTerminal.getTerminalOutput(), hasSize(0));
+        assertTrue(captureOutputTerminal.getOutput().isEmpty());
     }
 
     public void testThatCommandLogsNothingIfFileSystemDoesNotSupportOwners() throws Exception {
         executeCommand(jimFsConfigurationWithoutPermissions, new OwnerCheckFileCommand(createTempDir(), captureOutputTerminal, Mode.DISABLED));
-        assertThat(captureOutputTerminal.getTerminalOutput(), hasSize(0));
+        assertTrue(captureOutputTerminal.getOutput().isEmpty());
     }
 
     public void testThatCommandLogsIfGroupChanges() throws Exception {
         executeCommand(jimFsConfiguration, new GroupCheckFileCommand(createTempDir(), captureOutputTerminal, Mode.CHANGE));
-        assertThat(captureOutputTerminal.getTerminalOutput(), hasItem(allOf(containsString("Group of file ["), containsString("] used to be ["), containsString("], but now is ["))));
+        assertThat(captureOutputTerminal.getOutput(), allOf(containsString("Group of file ["), containsString("] used to be ["), containsString("], but now is [")));
     }
 
     public void testThatCommandLogsNothingIfGroupRemainsSame() throws Exception {
         executeCommand(jimFsConfiguration, new GroupCheckFileCommand(createTempDir(), captureOutputTerminal, Mode.KEEP));
-        assertThat(captureOutputTerminal.getTerminalOutput(), hasSize(0));
+        assertTrue(captureOutputTerminal.getOutput().isEmpty());
     }
 
     public void testThatCommandLogsNothingIfGroupIsDisabled() throws Exception {
         executeCommand(jimFsConfiguration, new GroupCheckFileCommand(createTempDir(), captureOutputTerminal, Mode.DISABLED));
-        assertThat(captureOutputTerminal.getTerminalOutput(), hasSize(0));
+        assertTrue(captureOutputTerminal.getOutput().isEmpty());
     }
 
     public void testThatCommandLogsNothingIfFileSystemDoesNotSupportGroups() throws Exception {
         executeCommand(jimFsConfigurationWithoutPermissions, new GroupCheckFileCommand(createTempDir(), captureOutputTerminal, Mode.DISABLED));
-        assertThat(captureOutputTerminal.getTerminalOutput(), hasSize(0));
+        assertTrue(captureOutputTerminal.getOutput().isEmpty());
     }
 
     public void testThatCommandDoesNotLogAnythingOnFileCreation() throws Exception {
@@ -130,7 +130,7 @@ public class CheckFileCommandTests extends ESTestCase {
             assertThat(Files.exists(path), is(true));
         }
 
-        assertThat(captureOutputTerminal.getTerminalOutput(), hasSize(0));
+        assertTrue(captureOutputTerminal.getOutput().isEmpty());
     }
 
     public void testThatCommandWorksIfFileIsDeletedByCommand() throws Exception {
@@ -147,7 +147,7 @@ public class CheckFileCommandTests extends ESTestCase {
             assertThat(Files.exists(path), is(false));
         }
 
-        assertThat(captureOutputTerminal.getTerminalOutput(), hasSize(0));
+        assertTrue(captureOutputTerminal.getOutput().isEmpty());
     }
 
     private void executeCommand(Configuration configuration, AbstractTestCheckFileCommand command) throws Exception {

qa/evil-tests/src/test/java/org/elasticsearch/common/cli/CliToolTests.java

@@ -20,7 +20,6 @@
 package org.elasticsearch.common.cli;
 
 import org.apache.commons.cli.CommandLine;
-import org.elasticsearch.ElasticsearchException;
 import org.elasticsearch.common.Strings;
 import org.elasticsearch.common.SuppressForbidden;
 import org.elasticsearch.common.settings.Settings;
@@ -133,7 +132,7 @@ public class CliToolTests extends CliToolTestCase {
     }
 
     public void testSingleCommandToolHelp() throws Exception {
-        CaptureOutputTerminal terminal = new CaptureOutputTerminal();
+        MockTerminal terminal = new MockTerminal();
         final AtomicReference<Boolean> executed = new AtomicReference<>(false);
         final NamedCommand cmd = new NamedCommand("cmd1", terminal) {
             @Override
@@ -145,12 +144,11 @@ public class CliToolTests extends CliToolTestCase {
         SingleCmdTool tool = new SingleCmdTool("tool", terminal, cmd);
         CliTool.ExitStatus status = tool.execute(args("-h"));
         assertStatus(status, CliTool.ExitStatus.OK_AND_EXIT);
-        assertThat(terminal.getTerminalOutput(), hasSize(3));
+        assertThat(terminal.getOutput(), containsString("cmd1 help"));
-        assertThat(terminal.getTerminalOutput(), hasItem(containsString("cmd1 help")));
     }
 
     public void testMultiCommandToolHelp() throws Exception {
-        CaptureOutputTerminal terminal = new CaptureOutputTerminal();
+        MockTerminal terminal = new MockTerminal();
         NamedCommand[] cmds = new NamedCommand[2];
         cmds[0] = new NamedCommand("cmd0", terminal) {
             @Override
@@ -167,12 +165,11 @@ public class CliToolTests extends CliToolTestCase {
         MultiCmdTool tool = new MultiCmdTool("tool", terminal, cmds);
         CliTool.ExitStatus status = tool.execute(args("-h"));
         assertStatus(status, CliTool.ExitStatus.OK_AND_EXIT);
-        assertThat(terminal.getTerminalOutput(), hasSize(3));
+        assertThat(terminal.getOutput(), containsString("tool help"));
-        assertThat(terminal.getTerminalOutput(), hasItem(containsString("tool help")));
     }
 
     public void testMultiCommandCmdHelp() throws Exception {
-        CaptureOutputTerminal terminal = new CaptureOutputTerminal();
+        MockTerminal terminal = new MockTerminal();
         NamedCommand[] cmds = new NamedCommand[2];
         cmds[0] = new NamedCommand("cmd0", terminal) {
             @Override
@@ -189,12 +186,11 @@ public class CliToolTests extends CliToolTestCase {
         MultiCmdTool tool = new MultiCmdTool("tool", terminal, cmds);
         CliTool.ExitStatus status = tool.execute(args("cmd1 -h"));
         assertStatus(status, CliTool.ExitStatus.OK_AND_EXIT);
-        assertThat(terminal.getTerminalOutput(), hasSize(3));
+        assertThat(terminal.getOutput(), containsString("cmd1 help"));
-        assertThat(terminal.getTerminalOutput(), hasItem(containsString("cmd1 help")));
     }
 
     public void testNonUserErrorPropagates() throws Exception {
-        CaptureOutputTerminal terminal = new CaptureOutputTerminal();
+        MockTerminal terminal = new MockTerminal();
         NamedCommand cmd = new NamedCommand("cmd", terminal) {
             @Override
             public CliTool.ExitStatus execute(Settings settings, Environment env) throws Exception {
@@ -225,22 +221,11 @@ public class CliToolTests extends CliToolTestCase {
     }
 
     public void testPromptForSetting() throws Exception {
-        final AtomicInteger counter = new AtomicInteger();
         final AtomicReference<String> promptedSecretValue = new AtomicReference<>(null);
         final AtomicReference<String> promptedTextValue = new AtomicReference<>(null);
-        final Terminal terminal = new MockTerminal() {
+        final MockTerminal terminal = new MockTerminal();
-            @Override
+        terminal.addTextInput("replaced");
-            public char[] readSecret(String text) {
+        terminal.addSecretInput("changeit");
-                counter.incrementAndGet();
-                return "changeit".toCharArray();
-            }
-
-            @Override
-            public String readText(String text) {
-                counter.incrementAndGet();
-                return "replaced";
-            }
-        };
         final NamedCommand cmd = new NamedCommand("noop", terminal) {
             @Override
             public CliTool.ExitStatus execute(Settings settings, Environment env) {
@@ -259,7 +244,6 @@ public class CliToolTests extends CliToolTestCase {
             System.clearProperty("es.replace");
         }
 
-        assertThat(counter.intValue(), is(2));
         assertThat(promptedSecretValue.get(), is("changeit"));
         assertThat(promptedTextValue.get(), is("replaced"));
     }
@@ -269,7 +253,7 @@ public class CliToolTests extends CliToolTestCase {
         final CliToolConfig.Cmd strictCommand = cmd("strict", CliTool.Command.Exit.class).stopAtNonOption(false).build();
         final CliToolConfig config = CliToolConfig.config("elasticsearch", CliTool.class).cmds(lenientCommand, strictCommand).build();
 
-        final CaptureOutputTerminal terminal = new CaptureOutputTerminal();
+        MockTerminal terminal = new MockTerminal();
         final CliTool cliTool = new CliTool(config, terminal) {
             @Override
             protected Command parse(String cmdName, CommandLine cli) throws Exception {
@@ -292,11 +276,11 @@ public class CliToolTests extends CliToolTestCase {
 
         // unknown parameters, error
         assertStatus(cliTool.execute(args("strict --unknown")), USAGE);
-        assertThat(terminal.getTerminalOutput(), hasItem(containsString("Unrecognized option: --unknown")));
+        assertThat(terminal.getOutput(), containsString("Unrecognized option: --unknown"));
 
-        terminal.getTerminalOutput().clear();
+        terminal.resetOutput();
         assertStatus(cliTool.execute(args("strict -u")), USAGE);
-        assertThat(terminal.getTerminalOutput(), hasItem(containsString("Unrecognized option: -u")));
+        assertThat(terminal.getOutput(), containsString("Unrecognized option: -u"));
     }
 
     private void assertStatus(CliTool.ExitStatus status, CliTool.ExitStatus expectedStatus) {

qa/evil-tests/src/test/java/org/elasticsearch/plugins/InstallPluginCommandTests.java

@@ -46,6 +46,7 @@ import org.apache.lucene.util.LuceneTestCase;
 import org.elasticsearch.Version;
 import org.elasticsearch.common.cli.CliTool;
 import org.elasticsearch.common.cli.CliToolTestCase;
+import org.elasticsearch.common.cli.MockTerminal;
 import org.elasticsearch.common.cli.Terminal;
 import org.elasticsearch.common.cli.UserError;
 import org.elasticsearch.common.settings.Settings;
@@ -116,8 +117,8 @@ public class InstallPluginCommandTests extends ESTestCase {
         return writeZip(structure, "elasticsearch");
     }
 
-    static CliToolTestCase.CaptureOutputTerminal installPlugin(String pluginUrl, Environment env) throws Exception {
+    static MockTerminal installPlugin(String pluginUrl, Environment env) throws Exception {
-        CliToolTestCase.CaptureOutputTerminal terminal = new CliToolTestCase.CaptureOutputTerminal(Terminal.Verbosity.NORMAL);
+        MockTerminal terminal = new MockTerminal();
         CliTool.ExitStatus status = new InstallPluginCommand(terminal, pluginUrl, true).execute(env.settings(), env);
         assertEquals(CliTool.ExitStatus.OK, status);
         return terminal;

qa/evil-tests/src/test/java/org/elasticsearch/plugins/ListPluginsCommandTests.java

@@ -28,6 +28,7 @@ import java.util.List;
 import org.apache.lucene.util.LuceneTestCase;
 import org.elasticsearch.common.cli.CliTool;
 import org.elasticsearch.common.cli.CliToolTestCase;
+import org.elasticsearch.common.cli.MockTerminal;
 import org.elasticsearch.common.cli.Terminal;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.env.Environment;
@@ -45,8 +46,8 @@ public class ListPluginsCommandTests extends ESTestCase {
         return new Environment(settings);
     }
 
-    static CliToolTestCase.CaptureOutputTerminal listPlugins(Environment env) throws Exception {
+    static MockTerminal listPlugins(Environment env) throws Exception {
-        CliToolTestCase.CaptureOutputTerminal terminal = new CliToolTestCase.CaptureOutputTerminal(Terminal.Verbosity.NORMAL);
+        MockTerminal terminal = new MockTerminal();
         CliTool.ExitStatus status = new ListPluginsCommand(terminal).execute(env.settings(), env);
         assertEquals(CliTool.ExitStatus.OK, status);
         return terminal;
@@ -62,29 +63,24 @@ public class ListPluginsCommandTests extends ESTestCase {
     }
 
     public void testNoPlugins() throws Exception {
-        CliToolTestCase.CaptureOutputTerminal terminal = listPlugins(createEnv());
+        MockTerminal terminal = listPlugins(createEnv());
-        List<String> lines = terminal.getTerminalOutput();
+        assertTrue(terminal.getOutput(), terminal.getOutput().isEmpty());
-        assertEquals(0, lines.size());
     }
 
     public void testOnePlugin() throws Exception {
         Environment env = createEnv();
         Files.createDirectory(env.pluginsFile().resolve("fake"));
-        CliToolTestCase.CaptureOutputTerminal terminal = listPlugins(env);
+        MockTerminal terminal = listPlugins(env);
-        List<String> lines = terminal.getTerminalOutput();
+        assertTrue(terminal.getOutput(), terminal.getOutput().contains("fake"));
-        assertEquals(1, lines.size());
-        assertTrue(lines.get(0).contains("fake"));
     }
 
     public void testTwoPlugins() throws Exception {
         Environment env = createEnv();
         Files.createDirectory(env.pluginsFile().resolve("fake1"));
         Files.createDirectory(env.pluginsFile().resolve("fake2"));
-        CliToolTestCase.CaptureOutputTerminal terminal = listPlugins(env);
+        MockTerminal terminal = listPlugins(env);
-        List<String> lines = terminal.getTerminalOutput();
+        String output = terminal.getOutput();
-        assertEquals(2, lines.size());
+        assertTrue(output, output.contains("fake1"));
-        Collections.sort(lines);
+        assertTrue(output, output.contains("fake2"));
-        assertTrue(lines.get(0).contains("fake1"));
-        assertTrue(lines.get(1).contains("fake2"));
     }
 }

qa/evil-tests/src/test/java/org/elasticsearch/plugins/PluginSecurityTests.java

@@ -31,7 +31,7 @@ import java.util.List;
 
 /** Tests plugin manager security check */
 public class PluginSecurityTests extends ESTestCase {
-    
+
     /** Test that we can parse the set of permissions correctly for a simple policy */
     public void testParsePermissions() throws Exception {
         assumeTrue("test cannot run with security manager enabled", System.getSecurityManager() == null);
@@ -42,7 +42,7 @@ public class PluginSecurityTests extends ESTestCase {
         PermissionCollection actual = PluginSecurity.parsePermissions(Terminal.DEFAULT, testFile, scratch);
         assertEquals(expected, actual);
     }
-    
+
     /** Test that we can parse the set of permissions correctly for a complex policy */
     public void testParseTwoPermissions() throws Exception {
         assumeTrue("test cannot run with security manager enabled", System.getSecurityManager() == null);
@@ -54,12 +54,12 @@ public class PluginSecurityTests extends ESTestCase {
         PermissionCollection actual = PluginSecurity.parsePermissions(Terminal.DEFAULT, testFile, scratch);
         assertEquals(expected, actual);
     }
-    
+
     /** Test that we can format some simple permissions properly */
     public void testFormatSimplePermission() throws Exception {
         assertEquals("java.lang.RuntimePermission queuePrintJob", PluginSecurity.formatPermission(new RuntimePermission("queuePrintJob")));
     }
-    
+
     /** Test that we can format an unresolved permission properly */
     public void testFormatUnresolvedPermission() throws Exception {
         assumeTrue("test cannot run with security manager enabled", System.getSecurityManager() == null);
@@ -70,7 +70,7 @@ public class PluginSecurityTests extends ESTestCase {
         assertEquals(1, permissions.size());
         assertEquals("org.fake.FakePermission fakeName", PluginSecurity.formatPermission(permissions.get(0)));
     }
-    
+
     /** no guaranteed equals on these classes, we assert they contain the same set */
     private void assertEquals(PermissionCollection expected, PermissionCollection actual) {
         assertEquals(asSet(Collections.list(expected.elements())), asSet(Collections.list(actual.elements())));

qa/evil-tests/src/test/java/org/elasticsearch/plugins/RemovePluginCommandTests.java

@@ -27,6 +27,7 @@ import java.nio.file.Path;
 import org.apache.lucene.util.LuceneTestCase;
 import org.elasticsearch.common.cli.CliTool;
 import org.elasticsearch.common.cli.CliToolTestCase;
+import org.elasticsearch.common.cli.MockTerminal;
 import org.elasticsearch.common.cli.Terminal;
 import org.elasticsearch.common.cli.UserError;
 import org.elasticsearch.common.settings.Settings;
@@ -48,8 +49,8 @@ public class RemovePluginCommandTests extends ESTestCase {
         return new Environment(settings);
     }
 
-    static CliToolTestCase.CaptureOutputTerminal removePlugin(String name, Environment env) throws Exception {
+    static MockTerminal removePlugin(String name, Environment env) throws Exception {
-        CliToolTestCase.CaptureOutputTerminal terminal = new CliToolTestCase.CaptureOutputTerminal(Terminal.Verbosity.VERBOSE);
+        MockTerminal terminal = new MockTerminal();
         CliTool.ExitStatus status = new RemovePluginCommand(terminal, name).execute(env.settings(), env);
         assertEquals(CliTool.ExitStatus.OK, status);
         return terminal;

test/framework/src/main/java/org/elasticsearch/common/cli/CliToolTestCase.java

@@ -19,7 +19,8 @@
 
 package org.elasticsearch.common.cli;
 
-import org.elasticsearch.ExceptionsHelper;
+import java.io.IOException;
+
 import org.elasticsearch.common.Strings;
 import org.elasticsearch.common.SuppressForbidden;
 import org.elasticsearch.test.ESTestCase;
@@ -27,14 +28,6 @@ import org.elasticsearch.test.StreamsUtils;
 import org.junit.After;
 import org.junit.Before;
 
-import java.io.IOException;
-import java.util.ArrayList;
-import java.util.List;
-
-import static org.hamcrest.Matchers.containsString;
-import static org.hamcrest.Matchers.greaterThan;
-import static org.hamcrest.Matchers.hasSize;
-
 public abstract class CliToolTestCase extends ESTestCase {
 
     @Before
@@ -56,63 +49,10 @@ public abstract class CliToolTestCase extends ESTestCase {
         return command.split("\\s+");
     }
 
-    /**
+    public static void assertTerminalOutputContainsHelpFile(MockTerminal terminal, String classPath) throws IOException {
-     * A terminal implementation that discards everything
+        String output = terminal.getOutput();
-     */
+        assertFalse(output, output.isEmpty());
-    public static class MockTerminal extends Terminal {
-
-        @Override
-        protected void doPrint(String msg) {}
-
-        @Override
-        public String readText(String prompt) {
-            return null;
-        }
-
-        @Override
-        public char[] readSecret(String prompt) {
-            return new char[0];
-        }
-    }
-
-    /**
-     * A terminal implementation that captures everything written to it
-     */
-    public static class CaptureOutputTerminal extends MockTerminal {
-
-        List<String> terminalOutput = new ArrayList<>();
-
-        public CaptureOutputTerminal() {
-            this(Verbosity.NORMAL);
-        }
-
-        public CaptureOutputTerminal(Verbosity verbosity) {
-            setVerbosity(verbosity);
-        }
-
-        @Override
-        protected void doPrint(String msg) {
-            terminalOutput.add(msg);
-        }
-
-        public List<String> getTerminalOutput() {
-            return terminalOutput;
-        }
-    }
-
-    public static void assertTerminalOutputContainsHelpFile(CliToolTestCase.CaptureOutputTerminal terminal, String classPath) throws IOException {
-        List<String> nonEmptyLines = new ArrayList<>();
-        for (String line : terminal.getTerminalOutput()) {
-            String originalPrintedLine = line.replaceAll(System.lineSeparator(), "");
-            if (Strings.isNullOrEmpty(originalPrintedLine)) {
-                nonEmptyLines.add(originalPrintedLine);
-            }
-        }
-        assertThat(nonEmptyLines, hasSize(greaterThan(0)));
-
         String expectedDocs = StreamsUtils.copyToStringFromClasspath(classPath);
-        for (String nonEmptyLine : nonEmptyLines) {
+        assertTrue(output, output.contains(expectedDocs));
-            assertThat(expectedDocs, containsString(nonEmptyLine.replaceAll(System.lineSeparator(), "")));
-        }
     }
 }

test/framework/src/main/java/org/elasticsearch/common/cli/MockTerminal.java

@@ -0,0 +1,85 @@
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.elasticsearch.common.cli;
+
+import java.io.ByteArrayOutputStream;
+import java.io.OutputStreamWriter;
+import java.io.PrintWriter;
+import java.io.UnsupportedEncodingException;
+import java.nio.charset.StandardCharsets;
+import java.util.ArrayDeque;
+import java.util.Deque;
+
+/**
+ * A terminal for tests which captures all output, and
+ * can be plugged with fake input.
+ */
+public class MockTerminal extends Terminal {
+
+    private final ByteArrayOutputStream buffer = new ByteArrayOutputStream();
+    private final PrintWriter writer = new PrintWriter(new OutputStreamWriter(buffer, StandardCharsets.UTF_8));
+    private final Deque<String> textInput = new ArrayDeque<>();
+    private final Deque<String> secretInput = new ArrayDeque<>();
+
+    public MockTerminal() {
+        super("\n"); // always *nix newlines for tests
+    }
+
+    @Override
+    public String readText(String prompt) {
+        if (textInput.isEmpty()) {
+            return null;
+        }
+        return textInput.removeFirst();
+    }
+
+    @Override
+    public char[] readSecret(String prompt) {
+        if (secretInput.isEmpty()) {
+            return null;
+        }
+        return secretInput.removeFirst().toCharArray();
+    }
+
+    @Override
+    public PrintWriter getWriter() {
+        return writer;
+    }
+
+    /** Adds an an input that will be return from {@link #readText(String)}. Values are read in FIFO order. */
+    public void addTextInput(String input) {
+        textInput.addLast(input);
+    }
+
+    /** Adds an an input that will be return from {@link #readText(String)}. Values are read in FIFO order. */
+    public void addSecretInput(String input) {
+        secretInput.addLast(input);
+    }
+
+    /** Returns all output written to this terminal. */
+    public String getOutput() throws UnsupportedEncodingException {
+        return buffer.toString("UTF-8");
+    }
+
+    /** Wipes the output. */
+    public void resetOutput() {
+        buffer.reset();
+    }
+}