Do not parse {displayName} placeholder for @ParameterizedTest using MessageFormat

documentation/src/docs/asciidoc/release-notes/release-notes-5.10.0-M1.adoc

@@ -58,6 +58,9 @@ repository on GitHub.
   `@MethodSource("myFactory([Ljava.lang.String;)`.
 * Exceptions thrown for undeletable files when cleaning up a temporary directory created
   via `@TempDir` now include the root cause.
+* The `{displayName}` placeholder of `@ParameterizedTest` is no longer parsed during the
+  evaluation of the `MessageFormat`, now `@DisplayName` and Kotlin method names can contain
+  single apostrophes and `MessageFormat` elements, such as `{data}`.
 
 ==== Deprecations and Breaking Changes
 

junit-jupiter-params/src/main/java/org/junit/jupiter/params/ParameterizedTestNameFormatter.java

@@ -31,6 +31,7 @@
 class ParameterizedTestNameFormatter {
 
 	private static final char ELLIPSIS = '\u2026';
+	private static final String DISPLAY_NAME_TEMPORARY_PLACEHOLDER = "__DISPLAY_NAME__";
 
 	private final String pattern;
 	private final String displayName;
@@ -61,7 +62,8 @@ private String formatSafely(int invocationIndex, Object[] arguments) {
 		String pattern = prepareMessageFormatPattern(invocationIndex, namedArguments);
 		MessageFormat format = new MessageFormat(pattern);
 		Object[] humanReadableArguments = makeReadable(format, namedArguments);
-		return format.format(humanReadableArguments);
+		String formatted = format.format(humanReadableArguments);
+		return formatted.replace(DISPLAY_NAME_TEMPORARY_PLACEHOLDER, this.displayName);
 	}
 
 	private Object[] extractNamedArguments(Object[] arguments) {
@@ -72,7 +74,7 @@ private Object[] extractNamedArguments(Object[] arguments) {
 
 	private String prepareMessageFormatPattern(int invocationIndex, Object[] arguments) {
 		String result = pattern//
-				.replace(DISPLAY_NAME_PLACEHOLDER, this.displayName)//
+				.replace(DISPLAY_NAME_PLACEHOLDER, DISPLAY_NAME_TEMPORARY_PLACEHOLDER)//
 				.replace(INDEX_PLACEHOLDER, String.valueOf(invocationIndex));
 
 		if (result.contains(ARGUMENTS_WITH_NAMES_PLACEHOLDER)) {

junit-jupiter-params/src/test/java/org/junit/jupiter/params/ParameterizedTestNameFormatterTests.java

@@ -60,6 +60,24 @@ void formatsDisplayName() {
 		assertEquals("enigma", formatter.format(2));
 	}
 
+	@Test
+	void formatsDisplayNameWithApostrophe() {
+		String displayName = "display'Zero";
+		var formatter = formatter(DISPLAY_NAME_PLACEHOLDER, "display'Zero");
+
+		assertEquals(displayName, formatter.format(1));
+		assertEquals(displayName, formatter.format(2));
+	}
+
+	@Test
+	void formatsDisplayNameContainingFormatElements() {
+		String displayName = "{enigma} {0} '{1}'";
+		var formatter = formatter(DISPLAY_NAME_PLACEHOLDER, displayName);
+
+		assertEquals(displayName, formatter.format(1));
+		assertEquals(displayName, formatter.format(2));
+	}
+
 	@Test
 	void formatsInvocationIndex() {
 		var formatter = formatter(INDEX_PLACEHOLDER, "enigma");

junit-jupiter-params/src/test/kotlin/ParameterizedTestNameFormatterIntegrationTests.kt

@@ -0,0 +1,62 @@
+/*
+ * Copyright 2015-2023 the original author or authors.
+ *
+ * All rights reserved. This program and the accompanying materials are
+ * made available under the terms of the Eclipse Public License v2.0 which
+ * accompanies this distribution and is available at
+ *
+ * https://www.eclipse.org/legal/epl-v20.html
+ */
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.TestInfo
+import org.junit.jupiter.params.ParameterizedTest
+import org.junit.jupiter.params.provider.ValueSource
+
+class ParameterizedTestNameFormatterIntegrationTests {
+
+    @ValueSource(strings = ["foo", "bar"])
+    @ParameterizedTest
+    fun `implicit'Name`(param: String, info: TestInfo) {
+        if (param.equals("foo")) {
+            assertEquals("[1] foo", info.displayName)
+        } else {
+            assertEquals("[2] bar", info.displayName)
+        }
+    }
+
+    @ValueSource(strings = ["foo", "bar"])
+    @ParameterizedTest(name = "{0}")
+    fun `zero'Only`(param: String, info: TestInfo) {
+        if (param.equals("foo")) {
+            assertEquals("foo", info.displayName)
+        } else {
+            assertEquals("bar", info.displayName)
+        }
+    }
+
+    @ValueSource(strings = ["foo", "bar"])
+    @ParameterizedTest(name = "{displayName}")
+    fun `displayName'Only`(param: String, info: TestInfo) {
+        assertEquals("displayName'Only(String, TestInfo)", info.displayName)
+    }
+
+    @ValueSource(strings = ["foo", "bar"])
+    @ParameterizedTest(name = "{displayName} - {0}")
+    fun `displayName'Zero`(param: String, info: TestInfo) {
+        if (param.equals("foo")) {
+            assertEquals("displayName'Zero(String, TestInfo) - foo", info.displayName)
+        } else {
+            assertEquals("displayName'Zero(String, TestInfo) - bar", info.displayName)
+        }
+    }
+
+    @ValueSource(strings = ["foo", "bar"])
+    @ParameterizedTest(name = "{0} - {displayName}")
+    fun `zero'DisplayName`(param: String, info: TestInfo) {
+        if (param.equals("foo")) {
+            assertEquals("foo - zero'DisplayName(String, TestInfo)", info.displayName)
+        } else {
+            assertEquals("bar - zero'DisplayName(String, TestInfo)", info.displayName)
+        }
+    }
+}