fix #1139 CI build

- fix NPEs in TrackPointCreator.fill()
- fix locale dependant tests
- wait for UI components
- extract utility functions into EspressoUtils

src/androidTest/java/de/dennisguse/opentracks/LocaleRule.java

@@ -0,0 +1,55 @@
+package de.dennisguse.opentracks;
+
+import android.content.res.Configuration;
+import android.content.res.Resources;
+import android.util.DisplayMetrics;
+
+import androidx.test.core.app.ApplicationProvider;
+
+import org.junit.rules.TestRule;
+import org.junit.runner.Description;
+import org.junit.runners.model.Statement;
+
+import java.util.Locale;
+
+public class LocaleRule implements TestRule {
+
+    private final Locale[] mLocales;
+    private Locale mDeviceLocale;
+
+
+    public LocaleRule(Locale... locales) {
+        assert locales != null && locales.length > 0;
+        mLocales = locales;
+    }
+
+    @Override
+    public Statement apply(Statement base, Description description) {
+        return new Statement() {
+            @Override
+            public void evaluate() throws Throwable {
+                try {
+                    mDeviceLocale = Locale.getDefault();
+                    for (Locale locale : mLocales) {
+                        setLocale(locale);
+                        base.evaluate();
+                    }
+                } finally {
+                    if (mDeviceLocale != null) {
+                        setLocale(mDeviceLocale);
+                    }
+                }
+            }
+        };
+    }
+
+    private void setLocale(Locale locale) {
+        Resources resources = ApplicationProvider.getApplicationContext().getResources();
+        Locale.setDefault(locale);
+        Configuration config = resources.getConfiguration();
+        config.setLocale(locale);
+        DisplayMetrics displayMetrics = resources.getDisplayMetrics();
+        resources.updateConfiguration(config, displayMetrics);
+    }
+
+}