chore: Introduce better constructor argument validation for the AppiumFieldDecorator class (appium#2070)

Author: mykola-mokhnach

src/main/java/io/appium/java_client/pagefactory/AppiumFieldDecorator.java

@@ -30,6 +30,7 @@
 import org.openqa.selenium.support.pagefactory.ElementLocatorFactory;
 import org.openqa.selenium.support.pagefactory.FieldDecorator;
 
+import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
 import java.lang.ref.WeakReference;
 import java.lang.reflect.Constructor;
@@ -44,6 +45,7 @@
 import java.util.List;
 import java.util.Map;
 
+import static com.google.common.base.Preconditions.checkNotNull;
 import static io.appium.java_client.pagefactory.utils.ProxyFactory.getEnhancedProxy;
 import static io.appium.java_client.pagefactory.utils.WebDriverUnpackUtility.unpackObjectFromSearchContext;
 import static io.appium.java_client.remote.options.SupportsAutomationNameOption.AUTOMATION_NAME_OPTION;
@@ -81,8 +83,7 @@ public class AppiumFieldDecorator implements FieldDecorator {
  * @param duration is a desired duration of the waiting for an element presence.
  */
  public AppiumFieldDecorator(SearchContext context, Duration duration) {
- this.webDriverReference = unpackObjectFromSearchContext(context, WebDriver.class)
- .map(WeakReference::new).orElse(null);
+ this.webDriverReference = requireWebDriverReference(context);
  this.platform = readStringCapability(context, CapabilityType.PLATFORM_NAME);
  this.automation = readStringCapability(context, AUTOMATION_NAME_OPTION);
  this.duration = duration;
@@ -109,8 +110,7 @@ public AppiumFieldDecorator(SearchContext context) {
  */
  AppiumFieldDecorator(WeakReference<SearchContext> contextReference, Duration duration) {
  var cr = contextReference.get();
- this.webDriverReference = unpackObjectFromSearchContext(cr, WebDriver.class)
- .map(WeakReference::new).orElse(null);
+ this.webDriverReference = requireWebDriverReference(cr);
  this.platform = readStringCapability(cr, CapabilityType.PLATFORM_NAME);
  this.automation = readStringCapability(cr, AUTOMATION_NAME_OPTION);
  this.duration = duration;
@@ -123,6 +123,22 @@ contextReference, duration, new WidgetByBuilder(platform, automation)
  );
  }
 
+ @Nonnull
+ private static WeakReference<WebDriver> requireWebDriverReference(SearchContext searchContext) {
+ var wd = unpackObjectFromSearchContext(
+ checkNotNull(searchContext, "The provided search context cannot be null"),
+ WebDriver.class
+ );
+ return wd.map(WeakReference::new)
+ .orElseThrow(() -> new IllegalArgumentException(
+ String.format(
+ "No driver implementing %s interface could be extracted from the %s instance. "
+ + "Is the provided search context valid?",
+ WebDriver.class.getName(), searchContext.getClass().getName()
+ )
+ ));
+ }
+
  @Nullable
  private String readStringCapability(SearchContext searchContext, String capName) {
  if (searchContext == null) {