Add back "invokeTestMethod" function to allow control over calling the test method. (#4474)

* Add back "invokeTestMethod" function to allow custom logic before and after tests.

* Improve TestAnnotationLocator.validateMethod

fabric-gametest-api-v1/src/main/java/net/fabricmc/fabric/api/gametest/v1/CustomTestMethodInvoker.java

@@ -0,0 +1,37 @@
+/*
+ * Copyright (c) 2016, 2017, 2018, 2019 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.fabric.api.gametest.v1;
+
+import java.lang.reflect.Method;
+
+import net.minecraft.test.TestContext;
+
+/**
+ * Implement this interface on test suites to provide custom logic for invoking {@link GameTest} test methods.
+ */
+public interface CustomTestMethodInvoker {
+	/**
+	 * Implement this method to provide custom logic used to invoke the test method.
+	 * This can be used to run code before or after each test.
+	 * You can also pass in custom parameters into the test method if desired.
+	 * The structure will have been placed in the world before this method is invoked.
+	 *
+	 * @param context The vanilla test context
+	 * @param method The test method to invoke
+	 */
+	void invokeTestMethod(TestContext context, Method method) throws ReflectiveOperationException;
+}

fabric-gametest-api-v1/src/main/java/net/fabricmc/fabric/impl/gametest/TestAnnotationLocator.java

@@ -37,6 +37,7 @@ import net.minecraft.test.TestEnvironmentDefinition;
 import net.minecraft.test.TestInstance;
 import net.minecraft.util.Identifier;
 
+import net.fabricmc.fabric.api.gametest.v1.CustomTestMethodInvoker;
 import net.fabricmc.fabric.api.gametest.v1.GameTest;
 import net.fabricmc.loader.api.FabricLoader;
 import net.fabricmc.loader.api.entrypoint.EntrypointContainer;
@@ -72,7 +73,7 @@ final class TestAnnotationLocator {
 		findMagicMethods(entrypoint, testClass, methods);
 
 		if (methods.isEmpty()) {
-			LOGGER.warn("No methods with the FabricGameTest annotation were found in {}", testClass.getName());
+			LOGGER.warn("No methods with the GameTest annotation were found in {}", testClass.getName());
 		}
 
 		return methods;
@@ -82,7 +83,11 @@ final class TestAnnotationLocator {
 	private void findMagicMethods(EntrypointContainer<Object> entrypoint, Class<?> testClass, List<TestMethod> methods) {
 		for (Method method : testClass.getDeclaredMethods()) {
 			if (method.isAnnotationPresent(GameTest.class)) {
-				validateMethod(method);
+				if (!CustomTestMethodInvoker.class.isAssignableFrom(testClass)) {
+					// Only validate the test method when using the default reflection invoker
+					validateMethod(method);
+				}
+
 				methods.add(new TestMethod(method, method.getAnnotation(GameTest.class), entrypoint));
 			}
 		}
@@ -93,21 +98,30 @@ final class TestAnnotationLocator {
 	}
 
 	private void validateMethod(Method method) {
+		List<String> issues = new ArrayList<>();
+
 		if (method.getParameterCount() != 1 || method.getParameterTypes()[0] != TestContext.class) {
-			throw new UnsupportedOperationException("Method %s must have a single parameter of type TestContext".formatted(method.getName()));
+			issues.add("must have a single parameter of type TestContext");
 		}
 
 		if (!Modifier.isPublic(method.getModifiers())) {
-			throw new UnsupportedOperationException("Method %s must be public".formatted(method.getName()));
+			issues.add("must be public");
 		}
 
 		if (Modifier.isStatic(method.getModifiers())) {
-			throw new UnsupportedOperationException("Method %s must not be static".formatted(method.getName()));
+			issues.add("must not be static");
 		}
 
 		if (method.getReturnType() != void.class) {
-			throw new UnsupportedOperationException("Method %s must return void".formatted(method.getName()));
+			issues.add("must return void");
 		}
+
+		if (issues.isEmpty()) {
+			return;
+		}
+
+		String methodName = method.getDeclaringClass().getName() + "#" + method.getName();
+		throw new UnsupportedOperationException("Test method (%s) has the following issues: %s".formatted(methodName, String.join(", ", issues)));
 	}
 
 	public record TestMethod(Method method, GameTest gameTest, EntrypointContainer<Object> entrypoint) {
@@ -118,8 +132,15 @@ final class TestAnnotationLocator {
 
 		Consumer<TestContext> testFunction() {
 			return context -> {
+				Object instance = entrypoint.getEntrypoint();
+
 				try {
-					method.invoke(entrypoint.getEntrypoint(), context);
+					if (instance instanceof CustomTestMethodInvoker customTestMethodInvoker) {
+						customTestMethodInvoker.invokeTestMethod(context, method);
+						return;
+					}
+
+					method.invoke(instance, context);
 				} catch (ReflectiveOperationException e) {
 					throw new RuntimeException("Failed to invoke test method", e);
 				}

fabric-gametest-api-v1/src/testmod/java/net/fabricmc/fabric/test/gametest/CustomTestInvokerTest.java

@@ -0,0 +1,44 @@
+/*
+ * Copyright (c) 2016, 2017, 2018, 2019 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.fabric.test.gametest;
+
+import java.lang.reflect.Method;
+
+import net.minecraft.block.Block;
+import net.minecraft.block.Blocks;
+import net.minecraft.test.TestContext;
+import net.minecraft.text.Text;
+import net.minecraft.util.math.BlockPos;
+
+import net.fabricmc.fabric.api.gametest.v1.CustomTestMethodInvoker;
+import net.fabricmc.fabric.api.gametest.v1.GameTest;
+
+public class CustomTestInvokerTest implements CustomTestMethodInvoker {
+	@Override
+	public void invokeTestMethod(TestContext context, Method method) throws ReflectiveOperationException {
+		context.setBlockState(0, 1, 0, Blocks.DIAMOND_BLOCK);
+
+		method.invoke(this, context, Blocks.DIAMOND_BLOCK);
+	}
+
+	@GameTest
+	public void testCustomInvoker(TestContext context, Block testBlock) {
+		context.addInstantFinalTask(() ->
+				context.checkBlock(new BlockPos(0, 1, 0), (block) -> block == testBlock, (b) -> Text.literal("Expect block to be diamond"))
+		);
+	}
+}

fabric-gametest-api-v1/src/testmod/resources/fabric.mod.json

@@ -7,6 +7,7 @@
   "license": "Apache-2.0",
   "entrypoints": {
     "fabric-gametest" : [
+      "net.fabricmc.fabric.test.gametest.CustomTestInvokerTest",
       "net.fabricmc.fabric.test.gametest.ExampleFabricTestSuite"
     ]
   }