diff --git a/config/src/test/java/io/confluent/common/config/AbstractConfigTest.java b/config/src/test/java/io/confluent/common/config/AbstractConfigTest.java
new file mode 100644
index 00000000000..e8c686fa7c4
--- /dev/null
+++ b/config/src/test/java/io/confluent/common/config/AbstractConfigTest.java
@@ -0,0 +1,114 @@
+/**
+ * Copyright 2017 Confluent Inc.
+ *
+ * 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 io.confluent.common.config;
+
+import org.junit.Test;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Properties;
+
+import static org.junit.Assert.*;
+
+/**
+ * Unit tests for class {@link AbstractConfig}.
+ *
+ * @see AbstractConfig
+ */
+public class AbstractConfigTest {
+
+  @Test
+  public void testGetPropsFromFileReturningEmptyProperties() {
+    Properties properties = AbstractConfig.getPropsFromFile(null);
+
+    assertTrue(properties.isEmpty());
+  }
+
+  @Test
+  public void testWithPrefixWithNonEmptyStringReturnsEmptyMap() {
+    ConfigDef configDef = new ConfigDef();
+    Map<Integer, Object> hashMap = new HashMap<>();
+    AbstractConfig abstractConfig = new AbstractConfig(configDef, hashMap);
+    Map<String, String> hashMapTwo = new HashMap<>();
+    hashMapTwo.put(",..", ",..");
+    Map<String, Object> map = abstractConfig.withPrefix(",..", hashMapTwo);
+
+    assertEquals(0, map.size());
+  }
+
+  @Test
+  public void testWithPrefixWithNonEmptyStrings() {
+    ConfigDef configDef = new ConfigDef();
+    Map<String, Object> hashMap = new HashMap<>();
+    hashMap.put("- asd1", "-asd");
+    hashMap.put(" asd1", "-asd");
+    AbstractConfig abstractConfig = new AbstractConfig(configDef, hashMap);
+    Map<String, Object> map = abstractConfig.withPrefix("-", hashMap);
+
+    assertEquals(1, map.size());
+    assertEquals(" asd1", map.keySet().iterator().next());
+    assertEquals(" asd1=-asd", map.entrySet().iterator().next().toString());
+  }
+
+  @Test
+  public void testFailsToCreateAbstractConfigThrowsConfigException() {
+    ConfigDef configDef = new ConfigDef();
+    Map<Object, Long> hashMap = new HashMap<>();
+    hashMap.put(configDef, new Long((-1995L)));
+
+    try {
+      new AbstractConfig(configDef, hashMap);
+      fail("Expecting exception: ConfigException");
+    } catch (ConfigException e) {
+      assertEquals(AbstractConfig.class.getName(), e.getStackTrace()[0].getClassName());
+    }
+  }
+
+  @Test
+  public void testGetStringThrowsConfigException() {
+    ConfigDef configDef = new ConfigDef();
+    Map<Integer, String> hashMap = new HashMap<>();
+    AbstractConfig abstractConfig = new AbstractConfig(configDef, hashMap);
+
+    try {
+      abstractConfig.getString(" could not be found.");
+      fail("Expecting exception: ConfigException");
+    } catch (ConfigException e) {
+      assertEquals(AbstractConfig.class.getName(), e.getStackTrace()[0].getClassName());
+    }
+  }
+
+  @Test
+  public void testValuesWithPrefix() {
+    ConfigDef configDef = new ConfigDef();
+    Map<Object, Boolean> hashMap = new HashMap<>();
+    AbstractConfig abstractConfig = new AbstractConfig(configDef, hashMap);
+    Map<String, Object> map = abstractConfig.valuesWithPrefix("");
+
+    assertEquals(0, map.size());
+  }
+
+  @Test
+  public void testOriginalsWithPrefix() {
+    ConfigDef configDef = new ConfigDef();
+    Map<Integer, String> hashMap = new HashMap<>();
+    AbstractConfig abstractConfig = new AbstractConfig(configDef, hashMap);
+    Map<String, Object> map = abstractConfig.originalsWithPrefix("~cOo+qt{k]k}#%y");
+
+    assertEquals(0, map.size());
+  }
+
+}
\ No newline at end of file
diff --git a/metrics/src/test/java/io/confluent/common/metrics/stats/PercentilesTest.java b/metrics/src/test/java/io/confluent/common/metrics/stats/PercentilesTest.java
new file mode 100644
index 00000000000..5fa89c06c47
--- /dev/null
+++ b/metrics/src/test/java/io/confluent/common/metrics/stats/PercentilesTest.java
@@ -0,0 +1,94 @@
+/**
+ * Copyright 2017 Confluent Inc.
+ *
+ * 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 io.confluent.common.metrics.stats;
+
+import io.confluent.common.metrics.MetricConfig;
+import io.confluent.common.metrics.MetricName;
+import org.junit.Test;
+
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.fail;
+
+/**
+ * Unit tests for class {@link Percentiles}.
+ *
+ * @see Percentiles
+ */
+public class PercentilesTest {
+
+  @Test
+  public void testValue() {
+    Percentiles.BucketSizing percentiles_BucketSizing = Percentiles.BucketSizing.LINEAR;
+    Percentiles percentiles = new Percentiles(1846, 1846, percentiles_BucketSizing, new Percentile[0]);
+    MetricConfig metricConfig = new MetricConfig();
+    percentiles.record(metricConfig, 28L, 1792L);
+
+    assertEquals(Double.POSITIVE_INFINITY, percentiles.value(metricConfig, 1846, 27.78662642648307), 0.01);
+  }
+
+  @Test
+  public void testFailsToCreatePercentilesTaking5ArgumentsThrowsIllegalArgumentException() {
+    try {
+      new Percentiles(44, (-121.169), 44, Percentiles.BucketSizing.LINEAR, null);
+      fail("Expecting exception: IllegalArgumentException");
+    } catch (IllegalArgumentException e) {
+      assertEquals(Percentiles.class.getName(), e.getStackTrace()[0].getClassName());
+    }
+  }
+
+  @Test
+  public void testFailsToCreatePercentilesTaking4ArgumentsThrowsIllegalArgumentException() {
+    try {
+      new Percentiles(58, 58, null, new Percentile[7]);
+      fail("Expecting exception: IllegalArgumentException");
+    } catch (IllegalArgumentException e) {
+      assertEquals(Percentiles.class.getName(), e.getStackTrace()[0].getClassName());
+    }
+  }
+
+  @Test
+  public void testCombineWithEmptyList() {
+    Percentiles.BucketSizing percentiles_BucketSizing = Percentiles.BucketSizing.LINEAR;
+    Percentile[] percentileArray = new Percentile[0];
+    Percentiles percentiles = new Percentiles(146, 1846, percentiles_BucketSizing, percentileArray);
+    MetricConfig metricConfig = new MetricConfig();
+    List<SampledStat.Sample> list = percentiles.samples;
+
+    assertEquals(Double.NaN, percentiles.combine(list, metricConfig, 1846), 0.01);
+  }
+
+  @Test
+  public void testStatsThrowsNullPointerException() {
+    Percentiles.BucketSizing percentiles_BucketSizing = Percentiles.BucketSizing.LINEAR;
+    Percentile[] percentileArray = new Percentile[2];
+    Map<String, String> hashMap = new HashMap<>();
+    MetricName metricName = new MetricName("|~a`", "|~a`", hashMap);
+    Percentile percentile = new Percentile(metricName, (-961));
+    percentileArray[0] = percentile;
+    Percentiles percentiles = new Percentiles((-961), 0.0, percentiles_BucketSizing, percentileArray);
+
+    try {
+      percentiles.stats();
+      fail("Expecting exception: NullPointerException");
+    } catch (NullPointerException e) {
+      assertEquals(Percentiles.class.getName(), e.getStackTrace()[0].getClassName());
+    }
+  }
+}
\ No newline at end of file