cache: added test that fails on zero values specs

+/**
+ * Copyright © 2016-2021 The Thingsboard Authors
+ *
+ * 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 org.thingsboard.server.cache;
+
+import lombok.extern.slf4j.Slf4j;
+import org.assertj.core.api.SoftAssertions;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.context.properties.EnableConfigurationProperties;
+import org.springframework.boot.test.context.SpringBootContextLoader;
+import org.springframework.context.annotation.ComponentScan;
+import org.springframework.test.context.ContextConfiguration;
+import org.springframework.test.context.junit.jupiter.SpringExtension;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+@ExtendWith(SpringExtension.class)
+@ContextConfiguration(classes = CaffeineCacheDefaultConfigurationTestSuite.class, loader = SpringBootContextLoader.class)
+@ComponentScan({"org.thingsboard.server.cache"})
+@EnableConfigurationProperties
+@Slf4j
+public class CaffeineCacheDefaultConfigurationTestSuite {
+
+    @Autowired
+    CaffeineCacheConfiguration caffeineCacheConfiguration;
+
+    @Test
+    public void verifyTransactionAwareCacheManagerProxy() {
+        assertThat(caffeineCacheConfiguration.getSpecs()).as("specs").isNotNull();
+        caffeineCacheConfiguration.getSpecs().forEach((name, cacheSpecs)->assertThat(cacheSpecs).as("cache %s specs", name).isNotNull());
+
+        SoftAssertions softly = new SoftAssertions();
+        caffeineCacheConfiguration.getSpecs().forEach((name, cacheSpecs)->{
+            softly.assertThat(name).as("cache name").isNotEmpty();
+            softly.assertThat(cacheSpecs.getTimeToLiveInMinutes()).as("cache %s time to live", name).isGreaterThan(0);
+            softly.assertThat(cacheSpecs.getMaxSize()).as("cache %s max size", name).isGreaterThan(0);
+        });
+        softly.assertAll();
+    }
+
+}