Add Gradle task for (re)generating test mapping files

build.gradle

@@ -44,6 +44,7 @@ allprojects {
 	spotless {
 		java {
 			licenseHeaderFile(rootProject.file("HEADER")).yearSeparator(", ")
+			targetExclude 'src/test/java/net/fabricmc/mappingio/lib/**/*.java'
 		}
 	}
 
@@ -183,8 +184,20 @@ jar {
 	}
 }
 
+tasks.register("generateTestMappings", JavaExec) {
+	dependsOn("testClasses")
+	classpath = sourceSets.test.runtimeClasspath
+	mainClass = 'net.fabricmc.mappingio.TestFileUpdater'
+}
+
+tasks.register("updateTestMappings", 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 {
+tasks.register("checkVersion") {
 	doFirst {
 		def xml = new URL("https://maven.fabricmc.net/net/fabricmc/mapping-io/maven-metadata.xml").text
 		def metadata = new XmlSlurper().parseText(xml)

mapping-io-extras/src/test/java/net/fabricmc/mappingio/extras/MappingTreeRemapperTest.java

@@ -19,20 +19,23 @@
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
+import java.io.IOException;
+
 import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.Test;
 import org.objectweb.asm.Type;
 
 import net.fabricmc.mappingio.TestHelper;
 import net.fabricmc.mappingio.tree.MappingTree;
+import net.fabricmc.mappingio.tree.MemoryMappingTree;
 
 public class MappingTreeRemapperTest {
 	private static MappingTree mappingTree;
 	private static MappingTreeRemapper remapper;
 
 	@BeforeAll
-	public static void setup() {
-		mappingTree = TestHelper.createTestTree();
+	public static void setup() throws IOException {
+		mappingTree = TestHelper.acceptTestMappings(new MemoryMappingTree());
 		remapper = new MappingTreeRemapper(mappingTree, "source", "target");
 	}
 

src/main/java/net/fabricmc/mappingio/format/enigma/EnigmaDirReader.java

@@ -48,6 +48,9 @@ public static void read(Path dir, MappingVisitor visitor) throws IOException {
 	}
 
 	public static void read(Path dir, String sourceNs, String targetNs, MappingVisitor visitor) throws IOException {
+		if (!Files.exists(dir)) throw new IOException("Directory does not exist: " + dir);
+		if (!Files.isDirectory(dir)) throw new IOException("Not a directory: " + dir);
+
 		Set<MappingFlag> flags = visitor.getFlags();
 		MappingVisitor parentVisitor = null;
 

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);
+			}
+		}
+	}
+}