Set Gradle version to 6.9.1, fix Junit and test case (#141)

* Set Gradle version to 6.9.1, fix Junit and test case

* Add misssing implementations

* add org.apache.openwhisk:openwhisk-tests
diff --git a/build.gradle b/build.gradle
index 4ebd4b8..a65389a 100644
--- a/build.gradle
+++ b/build.gradle
@@ -18,6 +18,7 @@
 buildscript {
     repositories {
         jcenter()
+        mavenCentral()
     }
     dependencies {
         classpath "cz.alenkacz:gradle-scalafmt:${gradle.scalafmt.version}"
diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
index d475d27..235e07d 100644
--- a/gradle/wrapper/gradle-wrapper.properties
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -18,4 +18,4 @@
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-5.5.1-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.9.1-bin.zip
diff --git a/gradlew b/gradlew
index d4ee78f..8e25e6c 100755
--- a/gradlew
+++ b/gradlew
@@ -7,7 +7,7 @@
 # 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
+#      https://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,
@@ -44,7 +44,7 @@
 APP_BASE_NAME=`basename "$0"`
 
 # Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='-Dfile.encoding=UTF-8'
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD="maximum"
diff --git a/gradlew.bat b/gradlew.bat
index ad0ff10..57b8698 100644
--- a/gradlew.bat
+++ b/gradlew.bat
@@ -5,7 +5,7 @@
 @rem you may not use this file except in compliance with the License.
 @rem You may obtain a copy of the License at
 @rem
-@rem      http://www.apache.org/licenses/LICENSE-2.0
+@rem      https://www.apache.org/licenses/LICENSE-2.0
 @rem
 @rem Unless required by applicable law or agreed to in writing, software
 @rem distributed under the License is distributed on an "AS IS" BASIS,
@@ -30,7 +30,7 @@
 set APP_HOME=%DIRNAME%
 
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=-Dfile.encoding=UTF-8
+set DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
 
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome
diff --git a/tests/build.gradle b/tests/build.gradle
index 09adf17..b718fb8 100644
--- a/tests/build.gradle
+++ b/tests/build.gradle
@@ -34,9 +34,12 @@
 }
 
 dependencies {
-    compile "org.scala-lang:scala-library:${gradle.scala.version}"
-    compile "org.apache.openwhisk:openwhisk-tests:${gradle.openwhisk.version}:tests"
-    compile "org.apache.openwhisk:openwhisk-tests:${gradle.openwhisk.version}:test-sources"
+    implementation "junit:junit:4.11"
+    implementation "org.scala-lang:scala-library:${gradle.scala.version}"
+    implementation "org.scalatest:scalatest_${gradle.scala.depVersion}:3.0.8"
+    implementation "org.apache.openwhisk:openwhisk-common:${gradle.openwhisk.version}"
+    implementation "org.apache.openwhisk:openwhisk-tests:${gradle.openwhisk.version}:tests"
+    implementation "org.apache.openwhisk:openwhisk-tests:${gradle.openwhisk.version}:test-sources"
     implementation group: 'com.typesafe.akka', name: "akka-http2-support_${gradle.scala.depVersion}", version: "${gradle.akka_http.version}"
     implementation group: 'com.typesafe.akka', name: "akka-http-xml_${gradle.scala.depVersion}", version: "${gradle.akka_http.version}"
     implementation group: 'com.typesafe.akka', name: "akka-discovery_${gradle.scala.depVersion}", version: "${gradle.akka.version}"