[Core] Indent pretty formatter stacktrace

Renders the stack trace in the pretty formatter with the same indent as
the step that failed it.

Before

```
[INFO] Running io.cucumber.skeleton.RunCucumberTest

Scenario: a few cukes               # io/cucumber/skeleton/belly.feature:3
  Given I have 42 cukes in my belly # io.cucumber.skeleton.StepDefinitions.I_have_cukes_in_my_belly(int)
    org.opentest4j.AssertionFailedError:
expected: "b"
 but was: "a"
  at java.base/jdk.internal.reflect.DirectConstructorHandleAccessor.newInstance(DirectConstructorHandleAccessor.java:62)
  at java.base/java.lang.reflect.Constructor.newInstanceWithCaller(Constructor.java:502)
  at io.cucumber.skeleton.StepDefinitions.I_have_cukes_in_my_belly(StepDefinitions.java:12)
  at ✽.I have 42 cukes in my belly(classpath:io/cucumber/skeleton/belly.feature:4)
```

After

```
[INFO] Running io.cucumber.skeleton.RunCucumberTest

Scenario: a few cukes               # io/cucumber/skeleton/belly.feature:3
  Given I have 42 cukes in my belly # io.cucumber.skeleton.StepDefinitions.I_have_cukes_in_my_belly(int)
      org.opentest4j.AssertionFailedError:
      expected: "b"
       but was: "a"
        at java.base/jdk.internal.reflect.DirectConstructorHandleAccessor.newInstance(DirectConstructorHandleAccessor.java:62)
        at java.base/java.lang.reflect.Constructor.newInstanceWithCaller(Constructor.java:502)
        at io.cucumber.skeleton.StepDefinitions.I_have_cukes_in_my_belly(StepDefinitions.java:12)
        at ✽.I have 42 cukes in my belly(classpath:io/cucumber/skeleton/belly.feature:4)
```

Author: mpkorstanje

CHANGELOG.md

@@ -12,6 +12,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ## [Unreleased]
 ### Fixed
 - [Core] Include root cause when using DataTable.asList and friends ([#2949](https://github.com/cucumber/cucumber-jvm/pull/2949) M.P. Korstanje)
+- [Core] Indent stacktrace in pretty formatter ([#2970](https://github.com/cucumber/cucumber-jvm/pull/2970) M.P. Korstanje)
 - [JUnit Platform Engine] Set Engine-Version-cucumber attribute ([#2963](https://github.com/cucumber/cucumber-jvm/pull/2963) M.P. Korstanje)
 
 ### Changed

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

@@ -49,8 +49,9 @@
 public final class PrettyFormatter implements ConcurrentEventListener, ColorAware {
 
     private static final String SCENARIO_INDENT = "";
-    private static final String STEP_INDENT = "  ";
-    private static final String STEP_SCENARIO_INDENT = "    ";
+    private static final String STEP_INDENT = SCENARIO_INDENT + "  ";
+    private static final String STEP_SCENARIO_INDENT = STEP_INDENT + "  ";
+    private static final String STACK_TRACE_INDENT = STEP_SCENARIO_INDENT + "  ";
 
     private final Map<UUID, Integer> commentStartIndex = new HashMap<>();
 
@@ -120,7 +121,7 @@ private void preCalculateLocationIndent(TestCaseStarted event) {
     private void printTags(TestCaseStarted event) {
         List<String> tags = event.getTestCase().getTags();
         if (!tags.isEmpty()) {
-            out.println(PrettyFormatter.SCENARIO_INDENT + String.join(" ", tags));
+            out.println(SCENARIO_INDENT + String.join(" ", tags));
         }
     }
 
@@ -187,21 +188,23 @@ private String formatLocationComment(
 
     private void printError(TestStepFinished event) {
         Result result = event.getResult();
-        printError(result);
+        printError(STACK_TRACE_INDENT, result);
     }
 
     private void printError(TestRunFinished event) {
         Result result = event.getResult();
-        printError(result);
+        printError(SCENARIO_INDENT, result);
     }
 
-    private void printError(Result result) {
+    private void printError(String prefix, Result result) {
         Throwable error = result.getError();
         if (error != null) {
             String name = result.getStatus().name().toLowerCase(ROOT);
             Format format = formats.get(name);
             String text = printStackTrace(error);
-            out.println("      " + format.text(text));
+            // TODO: Java 12+ use String.indent
+            String indented = text.replaceAll("(\r\n|\r|\n)", "$1" + prefix).trim();
+            out.println(prefix + format.text(indented));
         }
     }
 

cucumber-core/src/test/java/io/cucumber/core/options/CommandlineOptionsParserTest.java

@@ -39,6 +39,7 @@
 import java.util.regex.Pattern;
 
 import static io.cucumber.core.options.Constants.FILTER_TAGS_PROPERTY_NAME;
+import static io.cucumber.core.plugin.IsEqualCompressingLineSeparators.equalCompressingLineSeparators;
 import static io.cucumber.core.resource.ClasspathSupport.rootPackageUri;
 import static java.util.Arrays.asList;
 import static java.util.Collections.emptyMap;
@@ -50,7 +51,6 @@
 import static org.hamcrest.CoreMatchers.is;
 import static org.hamcrest.CoreMatchers.not;
 import static org.hamcrest.MatcherAssert.assertThat;
-import static org.hamcrest.Matchers.equalToCompressingWhiteSpace;
 import static org.hamcrest.collection.IsEmptyCollection.empty;
 import static org.hamcrest.collection.IsIterableContainingInOrder.contains;
 import static org.hamcrest.collection.IsMapContaining.hasEntry;
@@ -411,7 +411,7 @@ void ensure_less_than_1_thread_is_not_allowed() {
         parser
                 .parse("--threads", "0")
                 .build();
-        assertThat(output(), equalToCompressingWhiteSpace("--threads must be > 0"));
+        assertThat(output(), equalCompressingLineSeparators("--threads must be > 0"));
         assertThat(parser.exitStatus(), is(Optional.of((byte) 0x1)));
     }
 
@@ -518,7 +518,7 @@ void ensure_less_than_1_count_is_not_allowed() {
         parser
                 .parse("--count", "0")
                 .build();
-        assertThat(output(), equalToCompressingWhiteSpace("--count must be > 0"));
+        assertThat(output(), equalCompressingLineSeparators("--count must be > 0"));
         assertThat(parser.exitStatus(), is(Optional.of((byte) 0x1)));
     }
 

cucumber-core/src/test/java/io/cucumber/core/plugin/DefaultSummaryPrinterTest.java

@@ -19,11 +19,11 @@
 import java.util.Locale;
 import java.util.UUID;
 
+import static io.cucumber.core.plugin.IsEqualCompressingLineSeparators.equalCompressingLineSeparators;
 import static java.nio.charset.StandardCharsets.UTF_8;
 import static java.time.Instant.ofEpochSecond;
 import static java.util.Collections.singletonList;
 import static org.hamcrest.MatcherAssert.assertThat;
-import static org.hamcrest.text.IsEqualCompressingWhiteSpace.equalToCompressingWhiteSpace;
 
 class DefaultSummaryPrinterTest {
 
@@ -56,7 +56,7 @@ void does_not_print_duplicate_snippets() {
 
         bus.send(new TestRunFinished(bus.getInstant(), new Result(Status.PASSED, Duration.ZERO, null)));
 
-        assertThat(new String(out.toByteArray(), UTF_8), equalToCompressingWhiteSpace("" +
+        assertThat(new String(out.toByteArray(), UTF_8), equalCompressingLineSeparators("" +
                 "\n" +
                 "0 Scenarios\n" +
                 "0 Steps\n" +

cucumber-core/src/test/java/io/cucumber/core/plugin/IsEqualCompressingLineSeparators.java

@@ -0,0 +1,47 @@
+package io.cucumber.core.plugin;
+
+import org.hamcrest.Description;
+import org.hamcrest.Matcher;
+import org.hamcrest.TypeSafeMatcher;
+
+import java.util.Objects;
+
+public class IsEqualCompressingLineSeparators extends TypeSafeMatcher<String> {
+
+    private final String expected;
+
+    public IsEqualCompressingLineSeparators(String expected) {
+        Objects.requireNonNull(expected);
+        this.expected = expected;
+    }
+
+    public String getExpected() {
+        return expected;
+    }
+
+    @Override
+    public boolean matchesSafely(String actual) {
+        return compressNewLines(expected).equals(compressNewLines(actual));
+    }
+
+    @Override
+    public void describeMismatchSafely(String item, Description mismatchDescription) {
+      mismatchDescription.appendText("was ").appendValue(item);
+    }
+
+    @Override
+    public void describeTo(Description description) {
+        description.appendText("a string equal to ")
+                .appendValue(expected)
+                .appendText(" compressing newlines");
+    }
+
+    public String compressNewLines(String actual) {
+        return actual.replaceAll("[\r\n]+", "\n").trim();
+    }
+
+    public static Matcher<String> equalCompressingLineSeparators(String expectedString) {
+        return new IsEqualCompressingLineSeparators(expectedString);
+    }
+
+}

cucumber-core/src/test/java/io/cucumber/core/plugin/JsonFormatterTest.java

@@ -18,6 +18,8 @@
 
 import java.io.ByteArrayOutputStream;
 import java.io.InputStream;
+import java.io.PrintStream;
+import java.io.PrintWriter;
 import java.util.Scanner;
 import java.util.UUID;
 
@@ -1486,4 +1488,29 @@ void should_handle_several_features() throws JSONException {
         assertJsonEquals(expected, out);
     }
 
+    private static class StubException extends RuntimeException {
+
+        private final String stacktrace;
+
+        StubException(String message, String stacktrace) {
+            super(message);
+            this.stacktrace = stacktrace;
+        }
+
+        public StubException() {
+            this("message", "the stack trace");
+        }
+
+        @Override
+        public void printStackTrace(PrintWriter printWriter) {
+            printWriter.print(stacktrace);
+        }
+
+        @Override
+        public void printStackTrace(PrintStream printStream) {
+            printStream.print(stacktrace);
+        }
+
+    }
+
 }