content: /*
   * Copyright (C) 2021 The Android Open Source Project
   *
   * 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 androidx.test.internal.runner;
  
  import android.util.Log;
  import java.lang.reflect.Modifier;
  import org.junit.runner.Runner;
  import org.junit.runners.model.RunnerBuilder;
  
  /**
   * A class for loading JUnit3 and JUnit4 test classes given a set of potential class names.
   *
   * <p>This is a lenient loader intended for class path scanning cases, where if a class cannot be
   * loaded or is not a test it will be ignored.
   */
  class ScanningTestLoader extends TestLoader {
  
    private static final String LOG_TAG = "ScanningTestLoader";
  
    private final ClassLoader classLoader;
    private final RunnerBuilder runnerBuilder;
  
    ScanningTestLoader(ClassLoader classLoader, RunnerBuilder runnerBuilder) {
      this.classLoader = classLoader;
      this.runnerBuilder = runnerBuilder;
    }
  
    @Override
    protected Runner doCreateRunner(String className) {
      try {
        Class<?> loadedClass = Class.forName(className, false, classLoader);
        if (Modifier.isAbstract(loadedClass.getModifiers())) {
          logDebug("Skipping abstract class %s: not a test", loadedClass.getName());
          return null;
        }
        Runner runner = runnerBuilder.runnerForClass(loadedClass);
        if (runner instanceof EmptyTestRunner) {
          logDebug("Skipping class %s: class with no test methods", loadedClass.getName());
          return null;
        }
        return runner;
      } catch (Throwable e) {
        Log.w(LOG_TAG, String.format("Could not load class: %s", className), e);
        return null;
      }
    }
  
    /**
     * Utility method for logging debug messages. Only actually logs a message if LOG_TAG is marked as
     * loggable to limit log spam during normal use.
     */
    private static void logDebug(String msg, Object... objects) {
      if (Log.isLoggable(LOG_TAG, Log.DEBUG)) {
        Log.d(LOG_TAG, String.format(msg, objects));
      }
    }
  }
  