Only flush output frequently for ProgressFormatter

CHANGELOG.md

@@ -16,6 +16,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 ### Removed
 
 ### Fixed
+* [Core] Pretty print plugin performance issues; incorrect DataTable format in Gradle console ([#2541](https://github.com/cucumber/cucumber-jvm/pull/2541) Scott Davis)
 
 ## [7.3.2] (2022-04-22)
 

core/src/main/java/io/cucumber/core/plugin/NiceAppendable.java

@@ -11,9 +11,15 @@ final class NiceAppendable implements Appendable {
 
     private static final CharSequence NL = "\n";
     private final Appendable out;
+    private final boolean flushEveryWrite;
 
     public NiceAppendable(Appendable out) {
+        this(out, false);
+    }
+
+    public NiceAppendable(Appendable out, boolean flushEveryWrite) {
         this.out = out;
+        this.flushEveryWrite = flushEveryWrite;
     }
 
     public NiceAppendable println() {
@@ -55,6 +61,10 @@ private void tryFlush() {
             return;
         }
 
+        if (!flushEveryWrite) {
+            return;
+        }
+
         try {
             ((Flushable) out).flush();
         } catch (IOException e) {

core/src/main/java/io/cucumber/core/plugin/PrettyFormatter.java

@@ -181,14 +181,17 @@ private void printError(Result result) {
     }
 
     private void printText(WriteEvent event) {
+        // Prevent interleaving when multiple threads write to System.out
+        StringBuilder builder = new StringBuilder();
         try (BufferedReader lines = new BufferedReader(new StringReader(event.getText()))) {
             String line;
             while ((line = lines.readLine()) != null) {
-                out.println(STEP_SCENARIO_INDENT + line);
+                builder.append(String.format(STEP_SCENARIO_INDENT + line + "%n"));
             }
         } catch (IOException e) {
             throw new CucumberException(e);
         }
+        out.append(builder);
     }
 
     private void printEmbedding(EmbedEvent event) {
@@ -230,7 +233,6 @@ private String calculateLocationIndent(TestCase testStep, String prefix) {
         if (padding < 0) {
             return " ";
         }
-
         StringBuilder builder = new StringBuilder(padding);
         for (int i = 0; i < padding; i++) {
             builder.append(" ");

core/src/main/java/io/cucumber/core/plugin/ProgressFormatter.java

@@ -39,7 +39,9 @@ public final class ProgressFormatter implements ConcurrentEventListener, ColorAw
     private boolean monochrome = false;
 
     public ProgressFormatter(OutputStream out) {
-        this.out = new NiceAppendable(new UTF8OutputStreamWriter(out));
+        // Configure the NiceAppendable to flush on every append, since the
+        // point of this formatter is to display a progress bar.
+        this.out = new NiceAppendable(new UTF8OutputStreamWriter(out), true);
     }
 
     @Override
@@ -50,22 +52,28 @@ public void setMonochrome(boolean monochrome) {
     @Override
     public void setEventPublisher(EventPublisher publisher) {
         publisher.registerHandlerFor(TestStepFinished.class, this::handleTestStepFinished);
-        publisher.registerHandlerFor(TestRunFinished.class, event -> handleTestRunFinished());
+        publisher.registerHandlerFor(TestRunFinished.class, this::handleTestRunFinished);
     }
 
     private void handleTestStepFinished(TestStepFinished event) {
-        if (event.getTestStep() instanceof PickleStepTestStep || event.getResult().getStatus().is(Status.FAILED)) {
-            if (!monochrome) {
-                ANSI_ESCAPES.get(event.getResult().getStatus()).appendTo(out);
-            }
-            out.append(CHARS.get(event.getResult().getStatus()));
-            if (!monochrome) {
-                AnsiEscapes.RESET.appendTo(out);
-            }
+        boolean isTestStep = event.getTestStep() instanceof PickleStepTestStep;
+        boolean isFailedHookOrTestStep = event.getResult().getStatus().is(Status.FAILED);
+        if (!(isTestStep || isFailedHookOrTestStep)) {
+            return;
         }
+        // Prevent tearing in output when multiple threads write to System.out
+        StringBuilder buffer = new StringBuilder();
+        if (!monochrome) {
+            ANSI_ESCAPES.get(event.getResult().getStatus()).appendTo(buffer);
+        }
+        buffer.append(CHARS.get(event.getResult().getStatus()));
+        if (!monochrome) {
+            AnsiEscapes.RESET.appendTo(buffer);
+        }
+        out.append(buffer);
     }
 
-    private void handleTestRunFinished() {
+    private void handleTestRunFinished(TestRunFinished testRunFinished) {
         out.println();
         out.close();
     }

core/src/main/java/io/cucumber/core/plugin/UnusedStepsSummaryPrinter.java

@@ -68,6 +68,8 @@ private void finishReport() {
             String pattern = entry.getValue();
             out.println(format.text(location) + " # " + pattern);
         }
+
+        out.close();
     }
 
     @Override

core/src/test/java/io/cucumber/core/plugin/NiceAppendableTest.java

@@ -0,0 +1,53 @@
+package io.cucumber.core.plugin;
+
+import org.junit.jupiter.api.Test;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.OutputStreamWriter;
+
+import static io.cucumber.core.plugin.BytesEqualTo.isBytesEqualTo;
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+
+class NiceAppendableTest {
+
+    @Test
+    public void should_flush_every_call_if_configured() throws IOException {
+        ByteArrayOutputStream out = new ByteArrayOutputStream();
+        OutputStreamWriter writer = spy(new OutputStreamWriter(out));
+        NiceAppendable appendable = new NiceAppendable(writer, true);
+
+        appendable
+                .append("First String,")
+                .append("__Second String__", 2, 15)
+                .append("\n")
+                .println("Second line")
+                .println()
+                .close();
+
+        assertThat(out, isBytesEqualTo("First String,Second String\nSecond line\n\n"));
+        verify(writer, times(6)).flush(); // Each method call flushes
+    }
+
+    @Test
+    public void should_not_flush_unless_configured() throws IOException {
+        ByteArrayOutputStream out = new ByteArrayOutputStream();
+        OutputStreamWriter writer = spy(new OutputStreamWriter(out));
+        NiceAppendable appendable = new NiceAppendable(writer);
+
+        appendable
+                .append("First String,")
+                .append("__Second String__", 2, 15)
+                .append("\n")
+                .println("Second line")
+                .println()
+                .close();
+
+        assertThat(out, isBytesEqualTo("First String,Second String\nSecond line\n\n"));
+        verify(writer, times(0)).flush();
+    }
+
+}

core/src/test/java/io/cucumber/core/plugin/ProgressFormatterTest.java

@@ -0,0 +1,85 @@
+package io.cucumber.core.plugin;
+
+import io.cucumber.core.eventbus.EventBus;
+import io.cucumber.core.runtime.TimeServiceEventBus;
+import io.cucumber.plugin.event.HookTestStep;
+import io.cucumber.plugin.event.PickleStepTestStep;
+import io.cucumber.plugin.event.Result;
+import io.cucumber.plugin.event.TestCase;
+import io.cucumber.plugin.event.TestRunFinished;
+import io.cucumber.plugin.event.TestStepFinished;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import java.io.ByteArrayOutputStream;
+import java.time.Clock;
+import java.time.Duration;
+import java.time.Instant;
+import java.util.UUID;
+
+import static io.cucumber.core.plugin.BytesEqualTo.isBytesEqualTo;
+import static io.cucumber.plugin.event.Status.FAILED;
+import static io.cucumber.plugin.event.Status.PASSED;
+import static io.cucumber.plugin.event.Status.UNDEFINED;
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.mockito.Mockito.mock;
+
+class ProgressFormatterTest {
+
+    final EventBus bus = new TimeServiceEventBus(Clock.systemUTC(), UUID::randomUUID);
+    final ByteArrayOutputStream out = new ByteArrayOutputStream();
+    final ProgressFormatter formatter = new ProgressFormatter(out);
+
+    @BeforeEach
+    void setup() {
+        formatter.setEventPublisher(bus);
+    }
+
+    @Test
+    void prints_empty_line_for_empty_test_run() {
+        Result runResult = new Result(PASSED, Duration.ZERO, null);
+        bus.send(new TestRunFinished(Instant.now(), runResult));
+        assertThat(out, isBytesEqualTo("\n"));
+    }
+
+    @Test
+    void print_green_dot_for_passing_step() {
+        Result result = new Result(PASSED, Duration.ZERO, null);
+        bus.send(new TestStepFinished(Instant.now(), mock(TestCase.class), mock(PickleStepTestStep.class), result));
+        bus.send(new TestRunFinished(Instant.now(), result));
+        assertThat(out, isBytesEqualTo(AnsiEscapes.GREEN + "." + AnsiEscapes.RESET + "\n"));
+    }
+
+    @Test
+    void print_yellow_U_for_undefined_step() {
+        Result result = new Result(UNDEFINED, Duration.ZERO, null);
+        bus.send(new TestStepFinished(Instant.now(), mock(TestCase.class), mock(PickleStepTestStep.class), result));
+        bus.send(new TestRunFinished(Instant.now(), result));
+        assertThat(out, isBytesEqualTo(AnsiEscapes.YELLOW + "U" + AnsiEscapes.RESET + "\n"));
+    }
+
+    @Test
+    void print_nothing_for_passed_hook() {
+        Result result = new Result(PASSED, Duration.ZERO, null);
+        bus.send(new TestStepFinished(Instant.now(), mock(TestCase.class), mock(HookTestStep.class), result));
+        bus.send(new TestRunFinished(Instant.now(), result));
+        assertThat(out, isBytesEqualTo("\n"));
+    }
+
+    @Test
+    void print_red_F_for_failed_step() {
+        Result result = new Result(FAILED, Duration.ZERO, null);
+        bus.send(new TestStepFinished(Instant.now(), mock(TestCase.class), mock(PickleStepTestStep.class), result));
+        bus.send(new TestRunFinished(Instant.now(), result));
+        assertThat(out, isBytesEqualTo(AnsiEscapes.RED + "F" + AnsiEscapes.RESET + "\n"));
+    }
+
+    @Test
+    void print_red_F_for_failed_hook() {
+        Result result = new Result(FAILED, Duration.ZERO, null);
+        bus.send(new TestStepFinished(Instant.now(), mock(TestCase.class), mock(HookTestStep.class), result));
+        bus.send(new TestRunFinished(Instant.now(), result));
+        assertThat(out, isBytesEqualTo(AnsiEscapes.RED + "F" + AnsiEscapes.RESET + "\n"));
+    }
+
+}