Uncorrelation between the documentation and the actuall class 'InstrumentationRegistry' in android

Question

In the documentation of the class InstrumentationRegistry there's a method getTargetContext. But in the actuall class there's no such a method.

To import the class I used

import androidx.test.platform.app.InstrumentationRegistry;

How can I use InstrumentationRegistry.getTargetContext() appropriately?

The actuall class is that:

/*
 * Copyright (C) 2018 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.platform.app;

import android.app.Instrumentation;
import android.os.Bundle;
import java.util.concurrent.atomic.AtomicReference;

/**
 * An exposed registry instance that holds a reference to the instrumentation running in the process
 * and its arguments.
 *
 * <p>Instrumentation and InstrumentationRegistry are low level APIs, typically used by higher level
 * test frameworks. It is generally not recommended for direct use by most tests.
 */
public final class InstrumentationRegistry {

  private static final AtomicReference<Instrumentation> instrumentationRef =
      new AtomicReference<>(null);
  private static final AtomicReference<Bundle> arguments = new AtomicReference<>(null);

  /**
   * Returns the instrumentation currently running. Use this to get an {@link Instrumentation} into
   * your test.
   *
   * @throws IllegalStateException if instrumentation hasn't been registered
   */
  public static Instrumentation getInstrumentation() {
    Instrumentation instance = instrumentationRef.get();
    if (null == instance) {
      throw new IllegalStateException(
          "No instrumentation registered! " + "Must run under a registering instrumentation.");
    }
    return instance;
  }

  /**
   * Returns a copy of instrumentation arguments Bundle. Use this to get a {@link Bundle} containing
   * the command line arguments passed to {@link Instrumentation} into your test.
   *
   * <p>This Bundle is not guaranteed to be present under all instrumentations.
   *
   * @return Bundle the arguments for this instrumentation.
   * @throws IllegalStateException if no argument Bundle has been registered.
   */
  public static Bundle getArguments() {
    Bundle instance = arguments.get();
    if (null == instance) {
      throw new IllegalStateException(
          "No instrumentation arguments registered! "
              + "Are you running under an Instrumentation which registers arguments?");
    }
    return new Bundle(instance);
  }

  /**
   * Records/exposes the instrumentation currently running and stores a copy of the instrumentation
   * arguments Bundle in the registry.
   *
   * <p>This is a global registry - so be aware of the impact of calling this method!
   *
   * @param instrumentation the instrumentation currently running.
   * @param arguments the arguments for this application. Null deregisters any existing arguments.
   */
  public static void registerInstance(Instrumentation instrumentation, Bundle arguments) {
    instrumentationRef.set(instrumentation);
    InstrumentationRegistry.arguments.set(new Bundle(arguments));
  }

  private InstrumentationRegistry() {}
}

Answer 1

In this case, the document you were looking at is for the old testing support library. Note that the package name does not match the class you were using.

Here is the doc you actually want to use (this is for the AndroidX version of InstrumentationRegistry). Call the getInstrumentation() static method; the returned Instrumentation object will expose a getTargetContext() method.