Add Gradle task to regenerate test mapping files

build.gradle

@@ -183,6 +183,16 @@ jar {
 	}
 }
 
+task generateTestMappings(type: JavaExec, dependsOn: testClasses) {
+	classpath sourceSets.test.runtimeClasspath
+	mainClass = 'net.fabricmc.mappingio.TestFileUpdater'
+}
+
+task updateTestMappings(type: Copy, dependsOn: generateTestMappings) {
+	from 'build/resources/test/'
+	into 'src/test/resources/'
+}
+
 // A task to ensure that the version being released has not already been released.
 task checkVersion {
 	doFirst {

src/test/java/net/fabricmc/mappingio/TestFileUpdater.java

@@ -0,0 +1,46 @@
+/*
+ * Copyright (c) 2024 FabricMC
+ *
+ * Licensed 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 net.fabricmc.mappingio;
+
+import java.io.IOException;
+import java.nio.file.Path;
+
+import net.fabricmc.mappingio.format.MappingFormat;
+
+public class TestFileUpdater {
+	public static void main(String[] args) throws IOException {
+		for (MappingFormat format : MappingFormat.values()) {
+			if (!format.hasWriter) {
+				continue;
+			}
+
+			Path defaultPath = TestHelper.MappingDirs.VALID.resolve(TestHelper.getFileName(format));
+			Path holesPath = TestHelper.MappingDirs.VALID_WITH_HOLES.resolve(TestHelper.getFileName(format));
+			Path repeatPath = TestHelper.MappingDirs.REPEATED_ELEMENTS.resolve(TestHelper.getFileName(format));
+
+			TestHelper.acceptTestMappings(MappingWriter.create(defaultPath, format));
+			TestHelper.acceptTestMappingsWithHoles(MappingWriter.create(holesPath, format));
+
+			if (format != MappingFormat.ENIGMA_DIR) {
+				TestHelper.acceptTestMappingsWithRepeats(
+						MappingWriter.create(repeatPath, format),
+						format != MappingFormat.ENIGMA_FILE,
+						format != MappingFormat.ENIGMA_FILE);
+			}
+		}
+	}
+}