hawkBit repository uses Optional on single entity find/get requests (#435)

* Repo returns optionals.
* Improved exception handling for collection usage in repo queries.

Signed-off-by: kaizimmerm <kai.zimmermann@bosch-si.com>

hawkbit-security-core/pom.xml

@@ -71,16 +71,6 @@
          <artifactId>spring-boot-starter-test</artifactId>
          <scope>test</scope>
       </dependency>
-      <dependency>
-         <groupId>org.easytesting</groupId>
-         <artifactId>fest-assert-core</artifactId>
-         <scope>test</scope>
-      </dependency>
-      <dependency>
-         <groupId>org.easytesting</groupId>
-         <artifactId>fest-assert</artifactId>
-         <scope>test</scope>
-      </dependency>
       <dependency>
          <groupId>ru.yandex.qatools.allure</groupId>
          <artifactId>allure-junit-adaptor</artifactId>

hawkbit-security-core/src/test/java/org/eclipse/hawkbit/im/authentication/PermissionTest.java

@@ -8,7 +8,7 @@
  */
 package org.eclipse.hawkbit.im.authentication;
 
-import static org.fest.assertions.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import java.util.Collection;
 import java.util.List;

hawkbit-security-core/src/test/java/org/eclipse/hawkbit/security/ExcludePathAwareShallowETagFilterTest.java

@@ -8,7 +8,7 @@
  */
 package org.eclipse.hawkbit.security;
 
-import static org.fest.assertions.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThat;
 import static org.mockito.Mockito.mockingDetails;
 import static org.mockito.Mockito.times;
 import static org.mockito.Mockito.verify;

hawkbit-security-core/src/test/java/org/eclipse/hawkbit/util/IpUtilTest.java

@@ -9,7 +9,7 @@
 package org.eclipse.hawkbit.util;
 
 import static com.google.common.net.HttpHeaders.X_FORWARDED_FOR;
-import static org.fest.assertions.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThat;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;